Article

A New Marine Reptile (Sauropterygia) from New Zealand: Further Evidence for A Late Cretaceous Austral Radiation of Cryptoclidid Plesiosaurs

May 2002
Palaeontology 45(3):557 - 575

Authors:

University of Otago

Kaiwhekea katiki gen. et sp. nov. represents the first described cryptoclidid plesiosaurian from New Zealand. It is one of the largest cryptoclidids known, at a length of over 6.5 m, and represents the third reported genus of austral Late Cretaceous cryptoclidids. Kaiwhekea katiki is from siltstones of the Katiki Formation, upper Haumurian Stage (Cenomanian–Maastrichtian; c. 69–70 Ma) of coastal Otago, South Island, New Zealand. In the Late Cretaceous, the locality lay close to the polar circle. The holotype and only known specimen is an articulated skeleton with skull, preserved mostly as natural molds, but which lacks the forelimbs and pectoral girdle. The skull is relatively large and possesses several distinct characters, including a substantial, deep, jugal. There are about 43 upper and 42 lower teeth in each jaw quadrant; all are homodont, slim, and slightly recurved, lacking prominent ornament. Kaiwhekea probably took single soft-bodied prey. Based on cranial structure, it clearly belongs with the Cryptoclididae, but is not certainly close to the southern Late Cretaceous cryptoclidids Morturneria (Seymour Island, Antarctica) and Aristonectes (Chile, Argentina).

A new elasmosaurid (Plesiosauria: Sauropterygia) from the López de Bertodano Formation: new data on the evolution of the aristonectine morphology

Article

Apr 2024

A new elasmosaurid (Sauropterygia, Plesiosauria) from the upper levels of the La Colonia Formation (upper Maastrichtian), Chubut Province, Argentina

Article

Aug 2023
CRETACEOUS RES

A new elasmosaurid, Chubutinectes carmeloi gen. et sp. nov., from the Chubut Province, Argentina, is described. The holotype and only specimen of this species (MPEF-PV 5232) was collected from the La Colonia Formation. Chubutinectes carmeloi gen. et sp. nov. is among the few upper Maastrichtian elasmosaurids from the Southern Hemisphere whose postcranial anatomy is well known. It can be distinguished from other elasmosaurids by the following combination of characters: middle cervical centra longer than high with lateral keel and bilobate articular faces; pectoral and anterior dorsal centra with bilobate articular faces; coracoids with closed cordiform fenestra and long anterior coracoids process; high ratio coracoids/scapular length; ilium with angled shaft; pubis with small lateral cornua; humerus with posterior expansion ending in accessory facet and epipodial facets of humerus almost aligned; accessory ossification between tibia and tibial, and radius and radial. Preliminary phylogenetic analysis recovered Chubutinectes carmeloi gen. et sp. nov. within the Weddellonectia clade, including the Late Cretaceous Wedellian aristonectine elasmosaurids. The study of the associated microfossiliferous assemblages (micro- and nanofossils) indicates a marine inner neritic paleoenvironment, with restricted circulation and warm waters. The presence of Micula prinsii and Micula murus at this latitude indicates a latest Maastrichtian age, upper part of the UC20d sub-biozone and younger than ~67,3 Ma.

Plesiosaurs from the fluvial Kem Kem Group (mid-Cretaceous) of eastern Morocco and a review of non-marine plesiosaurs

Article

Jul 2022
CRETACEOUS RES

Plesiosaurs were a long-lived and widespread group of marine reptiles, with a worldwide distribution and a temporal range from the Late Triassic to the Late Cretaceous. Most occur in marine deposits, but some occur in low-salinity, brackish to freshwater environments. We report plesiosaurs from the freshwater fluvial deposits of the mid-Cretaceous (?Albian-Cenomanian) Kem Kem Group of Morocco. Remains include numerous shed teeth, vertebrae, and a humerus. The humerus represents a young juvenile; vertebrae likely belong to sub-adults. Teeth show heavy wear, similar to teeth of co-occurring spinosaurids. While coeval plesiosaurs from the Bahariya Formation of Egypt are members of Polycotylidae, the Kem Kem fossils show features of Leptocleididae, small-bodied plesiosaurs that were widely distributed in nearshore and non-marine settings in the Early Cretaceous. These fossils are the first freshwater plesiosaurs from Morocco, and are among the youngest representatives of Leptocleididae. The Kem Kem leptocleidids could have been infrequent visitors from the sea, freshwater-tolerant, or even freshwater-adapted, as in modern river dolphins. The abundance of shed teeth in the Kem Kem Group supports the hypothesis that they had some degree of freshwater tolerance. Furthermore, leptocleidids occur almost exclusively in shallow nearshore, brackish, or freshwater environments, suggesting adaptation to shallow, low-salinity environments. Other plesiosaur groups and other Mesozoic marine reptiles, including teleosaurids and mosasaurids, also occur in freshwater settings, suggesting plesiosaurs and other marine reptiles frequently exploited non-marine environments.

The cranial anatomy and relationships of Cardiocorax mukulu (Plesiosauria: Elasmosauridae) from Bentiaba, Angola

Article

Full-text available

Aug 2021
PLOS ONE

We report a new specimen of the plesiosaur Cardiocorax mukulu that includes the most complete plesiosaur skull from sub-Saharan Africa. The well-preserved three-dimensional nature of the skull offers rare insight into the cranial anatomy of elasmosaurid plesiosaurians. The new specimen of Cardiocorax mukulu was recovered from Bentiaba, Namibe Province in Angola, approximately three meters above the holotype. The new specimen also includes an atlas-axis complex, seventeen postaxial cervical vertebrae, partial ribs, a femur, and limb elements. It is identified as Cardiocorax mukulu based on an apomorphy shared with the holotype where the cervical neural spine is approximately as long anteroposteriorly as the centrum and exhibits a sinusoidal anterior margin. The new specimen is nearly identical to the holotype and previously referred material in all other aspects. Cardiocorax mukulu is returned in an early-branching or intermediate position in Elasmosauridae in four out of the six of our phylogenetic analyses. Cardiocorax mukulu lacks the elongated cervical vertebrae that is characteristic of the extremely long-necked elasmosaurines, and the broad skull with and a high number of maxillary teeth (28–40) which is characteristic of Aristonectinae. Currently, the most parsimonious explanation concerning elasmosaurid evolutionary relationships, is that Cardiocorax mukulu represents an older lineage of elasmosaurids in the Maastrichtian.

CT-scan description of Alexandronectes zealandiensis (Elasmosauridae, Aristonectinae), with comments on the elasmosaurid internal cranial features

Article

Jun 2021

The holotype specimen of Alexandronectes zealandiensis is analyzed using digital reconstruction based on CT scans. Additional information regarding internal anatomy or obscured details are added. Additional features include: ectopterygoid rhombic in shape with posterior end pointed, a feature shared only with Aristonectes quiriquinensis; pterygoid shows a high dorsal crest located anteriorly and laterally to the level of the basipterygoid process; posterior margin of parabasisphenoid medially notched in ventral view and surrounding anteriorly and laterally a midline pit. Two canals for XII nerve are present in the right exoccipital-opisthothic and only one in the left one. Supraoccipital with two medially curved ridges on its posterior surface. Additionally, the presence of a stapes is described for the first time in an aristonectine elasmosaurid. The inner ear labyrinth is described and compared with that of other plesiosaurs, and the floccular recess (osseous correlate of the floccular lobe of the cerebellum) is described for first time among elasmosaurids. This feature is probably related to the presence of a long neck and with predatory behavior as the floccular lobe (housed in the floccular recess) stabilized the head via the cervical musculature, and stabilized the retinal image during rotational head movements.

The most complete specimen of Kawanectes lafquenianum (Sauropterygia, Plesiosauria): New data on basicranial anatomy and possible sexual dimorphism in elasmosaurids

Article

Apr 2021
CRETACEOUS RES

José Patricio O'Gorman

Elasmosaurids are a cosmopolitan group of plesiosaurians that radiated during the Late Cretaceous. A new specimen of the small sized elasmosaurid Kawanectes lafquenianum is described here. New features of the basicranium and palate are added: basioccipital tubers with distal end deeply excavated, basioccipital ventral flat plate below occipital condyle, absence of posterior interpterygoid symphysis, parasphenoid extended caudally to the posterior margin of basioccipital condyle, craniocaudally short ventral keel of parasphenoid. Differences recorded between the specimens referred to K. lafquenianum (ilium shape, relative humerus to femur size and sacral centrum proportions) are described. Different explanations of these differences are discussed, concluding that sexual dimorphism is the most plausible explanation.

Cranial osteology of the mid-Cretaceous elasmosaurid Thalassomedon haningtoni from the Western Interior Seaway of North America

Article

Feb 2021

Thalassomedon haningtoni is one of the most completely preserved elasmosaurid plesiosaurians described to date. Unlike most other elasmosaurid fossils, both the holotype and a second referred specimen — which were recovered from the middle Cenomanian Graneros Shale in the mid-western USA — are represented by intact skulls with articulated postcranial skeletons. Thalassomedon haningtoni thus constitutes an ideal ‘model elasmosaurid taxon’ that contributes significant character state data towards resolving contested relationships within the clade. Here, we present a detailed reassessment of the cranial osteology of T. haningtoni with the aim of evaluating its disputed species-level monophyly, together with its broader phylogenetic affinities. We identify several key diagnostic cranial traits including a sharply tapered premaxillary rostrum with a pronounced dorsomedian ridge that extends to the tip of the snout, a proportionately very small and rounded external bony nasal opening, and an anisodont functional dentition that incorporates a pair of enlarged ‘fangs’ in the second maxillary tooth position. Our phylogenetic analyses using first-hand scores unequivocally support classification of the Graneros Shale specimens as conspecific. Furthermore, consistent nesting with other North American elasmosaurid taxa suggests that T. haningtoni could evidence successive lineage divergences that took place within the Western Interior Seaway during the middle to latest Cretaceous.

A non-aristonectine plesiosaur from Antarctica reveals new data on the mandibular symphysis of elasmosaurids

Article

Nov 2020

Elasmosaurids are one of the most abundant fossil marine reptile groups identified from the Upper Cretaceous strata of Antarctica. However, the documented record of intact elasmosaurid skull remains is scarce. In this study, we describe the first non-aristonectine elasmosaurid skeleton from Antarctica that preserves an associated lower jaw. This specimen displays a unique character state combination including three symphyseal alveoli, the angle between the mandibular rami exceeding 90°, and the absence of a ventral symphyseal sulcus or keel. This mandibular configuration has not been observed previously among elasmosaurids, prompting comparisons with other described examples and suggesting that mandibular morphology reached a variability peak during the Maastrichtian, which might be reflective of increased trophic diversity. José Patricio O’Gorman [joseogorman@fcnym.unlp.edu.ar], Paula Bona [paulabona26@gmail.com], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Godoy Cruz 2290, C1425FQB, CABA, Argentina. Martín de los Reyes [mdelosreyes@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; Instituto Antártico Argentino, 25 de Mayo 1143, B1650HMK, San Martín, Buenos Aires, Argentina; Maria Eugenia Raffi [eugeniaraffi@gmail.com] Centro Austral de Investigaciones Científicas, CONICET, Bernardo Houssay 200, Ushuaia, Argentina; Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina. Marcelo Reguero [regui@fcnym.unlp.edu.ar] División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; Instituto Antártico Argentino, 25 de Mayo 1143, B1650HMK, San Martín, Buenos Aires, Argentina.

Wunyelfia maulensis gen. et sp. nov., a new basal aristonectine (Plesiosauria, Elasmosauridae) from the Upper Cretaceous of central Chile (DOWNLOAD LINK ON ABSTRACT )

Article

Sep 2020

Your personalized Share Link: DOWNLOAD LINK https://authors.elsevier.com/a/1bxGViVLDCoqC We describe a near adult, partial postcranial skeleton of an elasmosaurid plesiosaur recovered from upper Maastrichtian beds of central Chile. The specimen includes the atlas-axis, five successive anterior-most cervical vertebrae, several middle cervical centra, cervical neural spines, most of the trunk centra, rib and gastralia fragments, anterior caudal centra and part of the pectoral girdle. Cervical centra have vertebral length indices consistent with adult aristonectines; also, their cervical neural spines are rostrally recurved and constricted in its base, which are features considered diagnostic of the clade Aristonectinae. Available Weddellian aristonectines preserving the atlas-axis were compared with the atlas-axis of the studied specimen. The new morphotype differs in size and sutural arrangements of the atlas-axis with respect to Aristonectes parvidens (upper Maastrichtian of Chubut, Argentina), Aristonectes quiriquinensis (upper Maastrichtian of central Chile) and Alexandronectes zealandiensis (lower Maastrichtian of New Zealand; at least based in its basioccipital condyle versus the atlantal cup of the studied specimen). The studied specimen also possesses anterior cervical vertebrae much different from those of Kaiwhekea katiki (lower Maastrichtian of New Zealand) and Morturneria seymourensis (upper Maastrichtian of Antarctica). Based on these observations, we refer it to a new aristonectine, Wunyelfia maulensis gen. et sp. nov., being the second representative of this clade known to date in the southeastern Pacific during the late Maastrichtian. Phylogenetic analysis recovers this new taxon as a basal aristonectine, consistent with its unique morphology, possessing an atlas-axis with features intermediate between non-aristonectine Weddellian elasmosaurids, and aristonectines.

Elasmosaurid phylogeny and paleobiogeography, with a reappraisal of Aphrosaurus furlongi from the Maastrichtian of the Moreno Formation

Article

Mar 2020

José Patricio O'Gorman

The holotype of the elasmosaurid Aphrosaurus furlongi from the Maastrichtian levels of the Moreno Formation is redescribed and considered a valid species based on one autapomorphy, a deep trough in the ventral surface of vertebral centra of the posterior cervicals, and the following combination of features: wide and short clavicle-interclavicle complex with concave anterior border and without posterior medial process or medial ventral keel, humerus with anterior depression, and posterior limb with accessory element on the posterior margin. The phylogenetic analysis recovered A. furlongi as an elasmosaurid within Weddellonectia. The phylogenetic analysis generated a new topology of Elasmosauridae. A new clade, Euelasmosaurida, is recovered, including all post-Cenomanian elasmosaurids other than Zarafasaura oceanis. Euelasmosaurida is composed of two main clades: Elasmosaurinae and Weddellonectia. The latter includes mostly Weddellian elasmosaurids, including Aristonectinae. Based on the new phylogenetic results, the evolution of key cranial and postcranial characters is discussed. Two key intervals of elasmosaurid evolutionary history are recognized: the Cenomanian, with the appearance of Euelasmosaurida, and the Santonian, with the differentiation of Weddellonectia and Elasmosaurinae.

Cretaceous Antarctic plesiosaurs: stratigraphy, systematics and paleobiogeography

Article

Full-text available

Jan 2019

The last twenty million years (Maastrichtian-Santonian) of Southern Hemisphere plesiosaur history is especially well recorded in the Weddellian Province (Patagonia; Western Antarctica and New Zealand). The oldest Late Cretaceous plesiosaurs, two specimens referred to Polycotylidae indet., come from the Santonian levels of the Santa Marta Formation, while the oldest elasmosaurids come from the lower Campanian of the same formation. In the lower Maastrichtian of the Snow Hill Island Formation the non-aristonectine elasmosaurid Vegasaurus molyi is recorded together with other non-diagnosable elasmosaurid specimens, but no aristonectines are present. Aristonectines appears in the Antarctic record in the upper Maastrichtian of the López de Bertodano Formation and are represented by Morturneria and cf. Aristonectes. The specimens from the upper Campanian previously referred to Aristonectinae indet. are referred to Elasmosauridae indet., shortening the temporal record of Aristonectinae in Antarctica. Therefore aristonectines appears in the Antarctic record in the upper Maastrichtian of the López de Bertodano Formation and are represented by Morturneria and cf. Aristonectes. The Antarctic Cretaceous elasmosaurids show a paleobiogeographic connection with South America and New Zealand (Weddellian Province). This connection is indicated by the shared presence of the Aristonectinae Kaiwhekea katiki (New Zealand) and Aristonectes (Argentina and Chile). Recent phylogenetic analysis recovered the aristonectines within the Weddellonectia clade, which includes the aristonectines and the non-aristonectines Vegasaurus molyi (Isla Vega, Antarctica); Kawanectes lafquenianum (Argentina); Morenosaurus stocki and Aphrosaurus furlongi (California). Among the Weddellonectia, the aristonectines show a relatively large body size and extremely derived features and probably occupied a trophic niche that differed from the trophic niche of other elasmosaurids. By way of contrast Kawanectes lafquenianum is an extremely small body-sized elasmosaurid restricted to marginal marine (probably estuarine) environments. Therefore the Weddellonectia show high morphological and probably high ecological diversity.

The first record of freshwater plesiosaurian from the Middle Jurassic of Gansu, NW China, with its implications to the local palaeobiogeography

Article

Full-text available

Dec 2019

Abstract Plesiosaurs are one of the common groups of aquatic reptiles in the Mesozoic, which mainly lived in marine environments. Freshwater plesiosaurs are rare in the world, especially from the Jurassic. The present paper reports the first freshwater plesiosaur, represented by four isolated teeth from the Middle Jurassic fluviolacustrine strata of Qingtujing area, Jinchang City, Gansu Province, Northwest China. These teeth are considered to come from one individual. The comparative analysis of the corresponding relationship between the body and tooth sizes of the known freshwater plesiosaur shows that Jinchang teeth represent a small-sized plesiosaurian. Based on the adaptive radiation of plesiosaurs and the palaeobiogeographical context, we propose a scenario of a river leading to the Meso-Tethys in the Late Middle Jurassic in Jinchang area, which may have provided a channel for the seasonal migration of plesiosaurs.

A giant elasmosaurid (Sauropterygia; Plesiosauria) from Antarctica: New information on elasmosaurid body size diversity and aristonectine evolutionary scenarios

Article

May 2019

Aristonectines show a highly derived morphology among elasmosaurid plesiosaurs, including some species with large body size. A new postcranial skeleton is described from the uppermost Maastrichtian levels of the López de Bertodano Formation, Seymour Island (= Marambio), Antarctica, being referred to as cf. Aristonectes sp; the most striking feature of the specimen described is its large body size, among the largest elasmosaurids worldwide. The occurrence of this specimen, located approximately 2.3 m or less below the Cretaceous-Paleogene (K/Pg) boundary, indicates the persistence of aristonectines at high latitudes and also it verifies their chronostratigraphical distribution until the end Cretaceous, before the mass extinction. Elasmosaurid diversity in terms of body size, possible relation of this body size, the trophic niche and abiotic drivers in aristonectine evolution are discussed. The body size inferred for MLP 89-III-3-1 seems to indicate an environment with high primary productivity, suggesting that these conditions persisted until the K/Pg mass extinction.

Reassessment of the Styxosaurus snowii (Williston, 1890) holotype specimen and its implications for elasmosaurid plesiosaurian interrelationships

Article

Nov 2018

The holotype (KUVP 1301) of Styxosaurus snowii—one of the earliest described elasmosaurid plesiosaurians—consists of a well-preserved cranium, mandible and articulated sequence of anterior–mid-series cervical vertebrae found in the lowermost Campanian strata of the Smoky Hill Chalk Member in the Niobrara Formation of Kansas, USA. This particular specimen has proven important for recent phylogenies of Elasmosauridae, and is integral to resulting definitions of the subfamily-level clade, Styxosaurinae. Despite this, KUVP 1301 has not been redescribed or figured in detail since its original taxonomic establishment. We, therefore, re-evaluated KUVP 1301 and assessed its phylogenetic implications. Several notable character states are pertinent for diagnosing S. snowii at genus and species level: (1) an anisodont functional dentition comprising enlarged premaxillary and dentary teeth with a pair of maxillary ‘fangs’, and elongate posterior-most dentary teeth that overlap the upper tooth row; (2) a prominent dorsomedian crest extending from the tip of the premaxillary rostrum, and expanding into a low ‘mound-like’ boss between the external bony nasal openings and orbits; (3) a pronounced convex projection on the posterolateral edge of the squamosals; and (4) platycoelous post-axial cervical vertebral centra that are substantially longer than high, and bear both lateral longitudinal ridges and ventral notches. Character state comparisons with the congeneric subfamily specifier Styxosaurus browni suggest that taxonomic distinction is possible, but equivocal. We, therefore, restrict our definition of Styxosaurus to morphologies observable in KUVP 1301. Furthermore, phylogenetic analysis of our first-hand data returns inconsistent elasmosaurid intra-clade relationships, especially with regard to Styxosaurinae. Consequently, we posit that a more targeted reassessment of Elasmosauridae is necessary to resolve both species-level topologies and higher taxonomy within the group.

Osteology of Aristonectes quiriquinensis (Elasmosauridae, Aristonectinae) from the upper Maastrichtian of central Chile

Article

Full-text available

Mar 2018

The upper Maastrichtian elasmosaurid plesiosaur Aristonectes quiriquinensis from central Chile is here redescribed following further preparation of the holotype. New cranial characters include a flattened skull with a caudal extension of the mandibular articulation far posterior to the occipital condyle; a very long, horizontal, and posteriorly oriented paroccipital process; mandible with restricted gape angle; and teeth oriented rostrally and not interlocking during occlusion. Postcranial features include the presence of very long extremities (ca. 3 m), whereas features of the caudal-most vertebrae suggest the presence of a horizontal caudal fin. Additionally, neuroanatomical features of Aristonectes are for the first time described based on a braincase cast. Integration of osteological features, anatomical comparisons, as well as taphonomic and environmental data strongly suggests that the foraging behavior of Aristonectes quiriquinensis incorporated a mix of engulfment and feeding from benthic sediments. This is a novelty among elasmosaurids, so far considered as mainly epipelagic feeders. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Otero, R. A., S. Soto-Acuña, and F. R. O'Keefe. 2018. Osteology of Aristonectes quiriquinensis (Elasmosauridae, Aristonectinae) from the upper Maastrichtian of central Chile. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1408638.

Virtual reexamination of a plesiosaurian specimen (Reptilia, Plesiosauria) from the Late Cretaceous (Turonian) of Goulmima, Morocco, using computed tomography

Article

Jun 2017

Turonian deposits of the Goulmima area, Er-Rachidia Province in southern Morocco, have yielded a diverse marine vertebrate fauna, including chondrichthyans, bony fishes, and large marine reptiles such as plesiosaurians, mosasauroids, and turtles. These fossils are included in ovoid calcareous nodules that are difficult to prepare. Moreover, bones may be partially or totally dissolved, making their study difficult. Using computed tomography, we have reconstructed the entire skull anatomy of SMNS 81783, one of the rare plesiosaurian specimens found in this locality and more generally in Africa. The digital three-dimensional reconstruction of the skull and the mandible offers for the first time the possibility to describe this specimen exhaustively. The new anatomical characters recorded confirm that SMNS 81783 belongs to Elasmosauridae on the basis of (1) slender and triangular skull; (2) beak index equal to 42%; (3) temporal fossa estimated to occupy about 40% of the skull length; (4) long process of the premaxillae extending posteriorly to meet the parietal above the orbit and separating the frontals; and (5) margin of the temporal fenestra lacking obvious contribution from the frontal. A preliminary phylogenetic analysis confirms its elasmosaurid affinity. The relationships between SMNS 81783, Libonectes atlasense, and Libonectes morgani, as well as the presence of stapes and pineal foramen, are discussed. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Allemand, R., N. Bardet, A. Houssaye, and P. Vincent. 2017. Virtual reexamination of a plesiosaurian specimen (Reptilia, Plesiosauria) from the Late Cretaceous (Turonian) of Goulmima, Morocco, using computed tomography. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1325894.

An integrated approach to understanding the role of the long neck in plesiosaurs

Article

Full-text available

Mar 2017

The evolution and function of the long neck in plesiosaurs, and how the problems associated with stiffness or flexibility were overcome during feeding, or rapid swimming during predator avoidance, are explored, and a new interpretation for the function of the plesiosaur neck is presented. Based on the anatomy of the articular faces of contiguous cervical vertebral centra, neural arches, and cervical ribs, the plesiosaur neck was mainly adapted for ventral bending, with dorsal, lateral and rotational movements all relatively restricted. Predominant ventral bending indicates the neck was adapted for use beneath the body, suggesting feeding in the water column, close to the sea floor, or within soft sediments on the sea floor. A new model is proposed for the plesiosaur bauplan, comprising the head as a filter, straining, sieve feeding or sediment raking apparatus, mounted on a neck which acted as a stiff but ventrally flexible feeding tube, attached to the body which acted as a highly mobile feeding platform. Numerous features of plesiosaurs, including cranial and dental form, cervical vertebral morphology, body shape and limb-based propulsion, conform to this model. Comparative data from modern organisms support this novel explanation for the structure and function of the plesiosaur long neck. This integrative analysis offers an explanation for the evolution of the plesiosaur long neck as a key evolutionary novelty, and why this apparently enigmatic feature remained a prominent feature of plesiosaurs throughout their long evolutionary history.

New data on one of the first plesiosaur (Reptilia, Sauropterygia) skeletons recovered from Antarctica, with comments on the dorsal sacral and regions of elasmosaurids

Article

Sep 2021

Elasmosaurids are among the most frequently recorded marine reptile fossils from the Campanian–Maastrichtian strata of Antarctica. Here, we describe one of the earliest quarried specimens, MLP 82-I-28-1, which is identified as a non-aristonectine elasmosaurid and phylogenetically nested within Weddellonectia. An ancestral states analysis of dorsal and sacral vertebral counts suggests that weddellonectian elasmosaurids plesiomorphically possessed between 17 and 18 dorsal vertebrae. The comparatively high count of 24 dorsal vertebrae observed in aristonectine elasmosaurids, such as Aristonectes quiriquinensis, thus likely represents a derived state correlated with the acquisition of larger body size. José O’Gorman [joseogorman@fcnym.unlp.edu.ar] División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA La Plata; CONICET: Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina, Godoy Cruz 2290, C1425FQB, CABA, Argentina; Franco Aspromonte [fran.aspromonte@gmail.com] División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA La Plata; Marcelo Reguero [mreguero@dna.gov.ar] División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA La Plata; Instituto Antártico Argentino, 25 de Mayo 1143, B1650HMK, San Martín, Buenos Aires, Argentina.

First record of a Lower Cretaceous (Hauterivian) plesiosaur from Chile

Article

Jul 2021
CRETACEOUS RES

Four vertebrae of a plesiosaur were recovered from the Katterfeld Formation of the Aysén Basin, north of Lago General Carrera, in the Patagonian Cordillera of Chile. Plesiosaur-bearing strata have been assigned to the Hauterivian based on ammonoid biostratigraphy, in particular they are inferred to be within the “Aegocrioceras and Crioceratites zone, of late Early-early Late Hauterivian age, above the Favrella Americana and below the “Favrella” wilckensis zones of previous authors. The preserved elements share anatomical characteristics with elasmosaurids, Muraenosaurus leedsii and an indeterminate plesiosaur of the Agrio Formation. However, more complete material is required to elucidate the affinity of plesiosaur present in the Katterfeld Formation. This finding represents the southernmost record of plesiosaurs in the Lower Cretaceous and the first record in the Hauterivian of Chile.

A new elasmosaurid (Sauropterygia: Plesiosauria) from the non-marine to paralic Dinosaur Park Formation of southern Alberta, Canada

Article

Full-text available

Feb 2021

Elasmosaurid plesiosaurian remains have been documented from non-marine to paralic (fluvial to estuarine) sediments of the upper Campanian Dinosaur Park Formation (DPF) of southern Alberta since 1898. Despite this long collection history, this material has received relatively little research attention, largely due to the highly fragmentary nature of most recovered specimens. However, this assemblage is significant, as it constitutes a rare occurrence of plesiosaurian remains in a non-marine depositional environment. This study reports on a recently collected and prepared specimen, which represents the most complete elasmosaurid yet collected from the DPF. This specimen preserves the trunk region, the base of the neck and tail, a partial fore and hind limb, and tooth, and is sufficiently complete to be assigned as the holotype of a new genus and species. This new taxon is diagnosed by a distinctive character state combination including a boomerang-shaped clavicular arch with acute anterior process, convex anterolateral margin, deeply embayed posterior margin, and pronounced ventral keel, together with the presence of 22 dorsal vertebrae, and the anterior dorsal centra bearing a ventral notch. The DPF plesiosaurian fossils were recovered from both estuarine/bay and fluvial palaeochannel sediments. The holotype skeleton represents an osteologically mature individual with an estimated body length of around 5 m, although the largest referred DPF elasmosaurid might have been closer to 7 m, which is considerably larger than other plesiosaurians reported from non-marine deposits. This suggests small-body lengths relative to typical elasmosaurids from marine settings, but is consistent with other plesiosaurians recovered from non-marine sediments. The identification of a distinct elasmosaurid taxon in the DPF might be evidence of niche-partitioning among the predominantly oceanic members of the ubiquitous plesiosaurian clade.

First record of Kawanectes lafquenianum (Plesiosauria, Elasmosauridae) from the La Colonia Formation of Argentina, with comments on the mandibular morphology of elasmosaurids

Article

Nov 2019

José Patricio O'Gorman

O’Gorman, J.P. 27 November, 2019. First record of Kawanectes lafquenianum (Plesiosauria, Elasmosauridae) from the La Colonia Formation of Argentina, with comments on the mandibular morphology of elasmosaurids. Alcheringa XX, XX–XX. ISSN 0311-5518 The elasmosaurid plesiosaur Kawanectes lafquenianum is recorded from the upper Campanian–Maastrichtian levels of the La Colonia Formation in Argentina for the first time, thus extending the stratigraphical range of this taxon, which was previously recorded only from the geographically proximal Allen Formation. The new fossils are referrable to K. lafquenianum on the basis of the large posterodistal projection on the humerus supporting an articular facet for a proximal supernumerary ossification, the presence of a depression anterior to the main muscle scar on ventral surface of the humeral shaft, and a high humerus/femur length ratio (∼1.2). Novel diagnostic character states for K. lafquenianum include the presence of a high triangular and distally pointed coronoid process on the mandible, a mandibular symphysis that incorporates 2.5 alveolar spaces on each ramus, and a retroarticular process without dorsal or medial inflexion. Relatively low b/a ratio (measure of coronoid–glenoid cavity length/preglenoid length) could suggest a mechanical advantage toward fast jaw closure and weak bite forces. Comparisons with other elamosaurids this imply that Southern Hemisphere weddellonectian taxa, such as K. lafquenianum, Aristonectes parvidens and Kaiwhekea katiki, were possibly adapted for rapid snapping bites. José Patricio O’Gorman [joseogorman@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina, CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina), Buenos Aires, Argentina.

A new basal elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany

Article

Full-text available

Aug 2017

Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.

A new elasmosaurid from the upper Maastrichtian López de Bertodano Formation: new data on weddellonectian diversity

Article

Jul 2017

O’Gorman, J.P., Panzeri, K.M., Fernández, M.S., Santillana, S., Moly, J.J. & Reguero, M. XX.XX.2017. A new elasmosaurid from the upper Maastrichtian López de Bertodano Formation: new data on weddellonectian diversity. Alcheringa xx, xxx–xxx. ISSN 0311-5518. Elasmosaurids are one of the most frequently recorded marine reptiles from the Weddellian Province (Patagonia, Western Antarctica and New Zealand). Improvements in our knowledge of elasmosaurid diversity have been problematic because of their conservative postcranial morphology. However, recent studies have helped to improved our understanding of the diversity of this group. Here, a new elasmosaurid specimen from the upper Maatrichtian horizons of the López de Bertodano Formation, Antarctica, MLP 14-I-20-16, is described. MLP 14-I-20-16 is one of the youngest non-aristonectine weddellonectian elasmosaurids from Antarctica. We confirm the coexistence of aristonectine and non-aristonectine elasmosaurids in Antarctica until the end of the Cretaceous. MLP 14-I-20-16 shows distinctive short and broad posterior cervical vertebrae, a feature only shared among the weddellonectian elasmosaurids by the Maastrichtian Morenosaurus stocki, although the same vertebral proportions are also recorded for the giant Cenomanian elasmosaurids Thalassomedon haningtoni. Comparison between MLP 14-I-20-16 and other elasmosaurids from the Maastrichtian of Antarctica indicates that at least two different non-aristonectine elasmosaurids were present in Antarctica during the late Maastrichtian. José P. O’Gorman, [joseogorman@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina, CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina; Karen M. Panzeri[panzerikaren@gmail.com], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; Marta S. Fernández [martafer@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; CONICET, Sergio Santillana [ssantillana@dna.gov.ar], Instituto Antártico Argentino, 25 De Mayo 1143, San Martín Provincia De Buenos Aires, Argentina; Juan J. Moly [juanjomoly@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; Marcelo Reguero[mreguero@dna.gov.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; Instituto Antártico Argentino, 25 De Mayo 1143, San Martín Provincia De Buenos Aires Argentina.

Isolated freshwater pliosaurid teeth from the Middle Jurassic Xintiangou Formation of Chongqing, China

Article

Full-text available

Oct 2023

The fossil vertebrate primary type specimens in the collection of the University of Otago Department of Geology

Article

Full-text available

Aug 2024

The 47 vertebrate type specimens held in the University of Otago Geology Department are catalogued in detail. A short history of the collection is followed by lists of the type specimens under the Classes Actinopterygii, Reptilia, Aves and Mammalia. A fish trace-fossil is included at the end of the Actinopterygii. Where appropriate, the name changes of the genus or species are given in chronological order. The specimens are briefly described, locality and geological age information is provided.

Body reconstruction and size estimation of plesiosaurs

Preprint

Full-text available

Feb 2024

Ruizhe Jackevan Zhao

Body size is the key to understanding many biological properties. Sizes of extinct animals are usually estimated from body reconstructions since their masses can not be weighed directly. Plesiosaurs were Mesozoic marine reptiles that were diverse in both body plan and size. Attempts to estimate body masses of plesiosaurs were rare in the past two centuries, possibly due to lack of knowledge about their postcranial anatomy and body shapes in life. The burst of plesiosaur studies in the past two decades has greatly expanded our cognition of their physiology, taxonomy, potential behavior and even soft body outlines. Here I present a comprehensive review of relevant knowledge, and propose a uniform set of methodology for rigorous body reconstruction of plesiosaurs. Twenty-two plesiosaur models were constructed under these criteria, and they were subsequently used as samples to find proxies for body mass. It is revealed that multiple skeletal elements are good indicators of plesiosaur size. This study offers scaling equations for size estimation, enabling quick acquisition of body mass information from fragmented fossils. A summary of body size evolution of different plesiosaur clades is also provided.

How Elongated? The Pattern of Elongation of Cervical Centra of Elasmosaurus platyurus with Comments on Cervical Elongation Patterns among Plesiosauromorphs

Article

Full-text available

Feb 2024
Diversity

José Patricio O'Gorman

Elasmosaurids comprise some of the most extreme morphotypes of plesiosaurs. Thus, the study of their neck and vertebrae elongation patterns plays a crucial role in understanding the anatomy of elasmosaurids. In this study, the taphonomic distortion of the holotype of Elasmosaurus platyurus and its effects on the vertebral length index (VLI) values are evaluated, and a new index to describe the neck is proposed (MAVLI = mean value of the vertebral elongation index of the anterior two-thirds of neck vertebrae). The results provide a strong foundation for a new scheme of neck elongation patterns that divide the diversity of the neck elongation of plesiosauriomorphs into three categories: not-elongate (MAVLI < 95 and Max VLI < 100), elongate (125 > MAVLI > 95 and 100 < Max VLI < 135), and extremely elongated (MAVLI > 125 and Max VLI > 135).

A long-tailed marine reptile from China provides new insights into the Middle Triassic pachypleurosaur radiation

Article

Full-text available

May 2022

Pachypleurosaurs (Pachypleurosauroidea) are a group of small to medium-sized, lizard-like marine reptiles in the Early to Middle Triassic, including Pachypleurosauridae, Keichousauridae and closely related taxa. The group is generally considered as a sauropterygian radiation, but its phylogenetic interrelationships remain highly debated. Here, we present a new pachypleurosaurid, Honghesaurus longicaudalis gen. et sp. nov., from the early Middle Triassic (Anisian, ~ 244 Ma) marine deposits in Luxi, Yunnan, China. The discovery documents the first really long-tailed pachypleurosaur with totally 121 (69 caudal) vertebrae, providing new evidence for the vertebral multiplication and ecological adaption of this group. The long trunk associated with an incredibly long tail could provide Honghesaurus the advantage of maneuverability and energy efficiency for lateral undulatory swimming. Honghesaurus, although possessing a series of autapomorphies, fills the morphological gap between Qianxisaurus from the Ladinian Xingyi Biota and Wumengosaurus from the Anisian Panxian Biota. Phylogenetic studies unite these three pachypleurosaurids as a monophyletic clade above European pachypleurosaurid clades and provide new insights into the interrelationships of this group. Our scenario of pachypleurosaurian phylogeny combined with the stratigraphic data imply that the Tethys Ocean was a west–east corridor for dispersal of pachypleurosaurids from Europe into South China.

Cryptoclidid plesiosaurs (Sauropterygia, Plesiosauria) from the Upper Jurassic of the Atacama Desert

Article

Jul 2020

This study presents the first plesiosaurs recovered from the Jurassic of the Atacama Desert that are informative at the genus level. One specimen is represented by an articulated axial section that shows distinctive features, such as cervical vertebrae with oval articular facets and gracile neural pedicles. The second specimen preserves similar vertebrae, teeth, propodials, and pectoral elements. Their anatomical characteristics allow us to refer them to Muraenosaurus, a genus of cryptoclidid plesiosaur previously reported in Callovian rocks of Europe and Argentina. A third specimen is represented by a fragmentary jaw, which coincides precisely in size and anatomical features with that of Vinialesaurus caroli, another cryptoclidid plesiosaur exclusively known from the Oxfordian of Cuba. The material studied represents the first record of Muraenosaurus in the Oxfordian of the Profeta-La Ternera Basin in northern Chile, adding to previous regional occurrences of the genus and to the record of Cryptoclidus, both also known from the Callovian of Argentina. On the other hand, the specimen referred to Vinialesaurus is the first appearance of this genus in the Southern Hemisphere. These new records give strong support to the exchange of marine vertebrates between the northern Tethys and the southern Pacific through the Caribbean Seaway during the Middle and Late Jurassic.

Paleoenvironmental context and significance of a partial elasmosaurid skeleton from the Albian of Haute-Provence, France

Article

Full-text available

Apr 2020

The Early–Late Cretaceous transition (late Albian–early Cenomanian; ~100 Ma) witnessed marked environmental changes and a deep reorganization of the marine fauna. The impact of these environmental and biotic changes on Tethyan marine vertebrates is poorly understood, due to a fragmentary fossil record. Here we report upper Albian marine vertebrate remains, including a partially articulated plesiosaurian skeleton, from a fossiliferous glauconite-rich bed in the Alpes de Haute-Provence, France. The fossiliferous horizon produced a diversified invertebrate fauna including ammonoids and belemnoids. The ammonite fauna is abundant and diversified, indicating the Mortoniceras fallax ammonite Zone. The calcareous nannofossil biomarkers date the bed to the NC10a Zone. The fossiliferous bed consists of glauconitic marls enriched in planktic foraminifera and occurs amongst a monotonous succession of alternating marlstones and limestone beds. The vertebrate fauna consists of chondrichthyans and marine reptiles. Chondrichthyans are represented by five Lamniformes species (dominated by Sphenodus) and comprise predator taxa probably living in open marine temperate waters. The site yielded a large, partial post-cranial plesiosaurian skeleton with articulated elements, belonging to an elasmosaurid and representing one of the most complete Albian plesiosaurian specimens known from Europe. The abundance and preservation of the collected fossil remains are best explained by their concentration during a basin-scale episode of very low sedimentation corresponding to a major episode of marine transgression, associated with a lower oxygenation of bottom waters. These findings indicate that the newly discovered fossiliferous bed holds promising clues about the evolutionary history of major groups of marine vertebrates and ammonites near the Early–Late Cretaceous transition.

Plesiosaur remains associated with a rich marine fauna from the Albian of southeastern France

Poster

Jul 2018

The Early-Late Cretaceous transition (Late Albian-Early Cenomanian; ~100 Ma) witnessed marked environmental changes and a deep reorganization of the marine fauna. Nevertheless, the impact of these environmental and biotic changes on Eurasian marine vertebrates remains poorly understood, as specimens from this area are mostly represented by fragmentary and isolated remains occurring in reworked, bonebed-like deposits. Here we report vertebrate remains from an upper Albian marine fossiliferous bed from the Geological Reserve of Digne (Alpes-de Haute-Provence, southeastern France), recovered with diverse invertebrate species (ammonoids, belemnoids, brachiopods and inoceramid bivalves). The fossiliferous bed consists of glauconitic marls enriched in planktic foraminifera and occurs within an expanded and monotonous succession of micaceous marls interbedded with silty carbonate levels that were deposited in the pelagic domain of the SE French Basin. The ammonite fauna is quite exceptional by its abundance, diversity and quality of preservation (i.e., large specimens preserving very fragile shell features that are generally not fossilized) and indicate that the investigated bed belong to the Mortoniceras fallax ammonite Biozone (Middle-Late Albian). The diverse vertebrate fauna consists of chondrichthyans, ichthyosaurs and plesiosaurs. Chondrichthyans are represented by five shark species belonging to the order Lamniformes. This shark assemblage is dominated by Sphenodus teeth and comprises predator taxa probably living in temperate waters and indicative of open marine settings. The site yielded a large, partial post-cranial plesiosaur skeleton with articulated elements probably belonging to an elasmosaurid (long necked) taxa and representing one of the most complete Albian plesiosaur specimen known from Europe. These findings indicate that this new paleontological site holds promising clues about the evolutionary history of major groups of marine vertebrates near the Early-Late Cretaceous transition.

The first non-aristonectine elasmosaurid (Sauropterygia; Plesiosauria) cranial material from Antarctica: New data on the evolution of the elasmosaurid basicranium and palate

Article

Mar 2018

Elasmosaurids are a monophyletic group of cosmopolitan plesiosaurs with extremely long necks. Although abundant elasmosaurid material has been collected from the Upper Cretaceous of Antarctica, skull material is extremely rare. Here, new elasmosaurid cranial material from the lower Maastrichtian levels of the Cape Lamb Member (Snow Hill Island Formation) on Vega Island, Antarctica is described. The studied specimen (MLP 15-I-7-6) is a non-aristonectine elasmosaurid but shows a palate morphology characterized by the absence of a posterior interpterygoid symphysis and a posterior plate-like extension of the pterygoids, features previously associated with the aristonectine palatal structure. The specimen MLP 15-I-7-6 thus provides an indication that these palatal features are also present in non-aristonectine Weddellian elasmosaurids, and makes available additional evidence of the close phylogenetical relationship between the aristonectines and some Weddellian non-aristonectine elasmosaurids.

Eggs for breakfast? Analysis of a probable mosasaur biting trace on the Cretaceous echinoid Echinocorys ovata Leske, 1778

Article

Full-text available

Feb 2018

Fossil biting traces (praedichnia) represent indirect evidence of predation and shed light on fossil predator–prey interactions and fossil food webs. Especially from echinoderm skeletons, biting traces are well known. Here, we describe the oral surface of a large Cretaceous (Maastrichtian) holasteroid echinoid Echinocorys ovata Leske, 1778 from Hemmoor (northern Germany) which exhibits four circular punctures arranged in a semi-circular arc. Whereas three of the punctures penetrated the skeleton, one puncture only just hit the margin of the echinoid test at the ambitus, leaving a long incision furrow in the skeleton. The punctures were not lethal to the sea urchin as is indicated by progressed skeletal regeneration and closure of the fractures. The overall appearance of the punctures suggests that they were produced during a single mechanical event, most likely by the biting action of the teeth of a large vertebrate animal. We analysed the shape and arrangement of the biting trace and conclude that it was probably produced by a marine reptile possessing a prognath tooth position, most likely by a globidensine mosasauroid. Our finding not only sheds light on mosasaur feeding behaviour and prey selection but also increases the knowledge of the food webs in the chalk sea ecosystem during the uppermost Cretaceous.

A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods

Article

Dec 2017

Kear, B.P., Fordyce, R.E., Hiller, N. & Siversson, M., December 2017. A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods. Alcheringa 00, 000-000. ISSN 0311-5518. THE LAST 15 years has witnessed a blossoming of research on Australasian Mesozoic marine tetrapod fossils. Much of this work has focused on amniotes, particularly those from the prolific Lower Cretaceous (Aptian–Albian) Lagerstätten of the Eromanga Basin in central and eastern Australia, and Upper Cretaceous (Campanian–Maastrichtian) sequences of the North and South islands of New Zealand. However, rare and less popularized remains have also been found in Lower Triassic–mid-Cretaceous rocks from Australia, New Zealand and the Chatham Islands, and on the tectonically proximal landmasses of New Caledonia and Timor. Currently identified taxa include estuarine–paralic rhytidostean, brachyopid, capitosaurian and trematosaurian temnospondyls from the earliest Triassic (Induan–Olenekian), Middle–Late Triassic (Anisian–Norian) eosauropterygians, and mixosaurian, shastasaurian and euichthyosaurian ichthyosaurians, Early–Middle Jurassic (Sinemurian–Bajocian) ichthyosaurians, together with plesiosauroid and rhomaleosaurid-like plesiosaurians, and diverse Early (Aptian–Albian) through to Late Cretaceous (Campanian–Maastrichtian) elasmosaurid, leptocleidid, polycotylid, probable cryptoclidid and pliosaurid plesiosaurians, as well as ophthalmosaurid ichthyosaurians, sea turtles incorporating protostegids, and mosasaurid squamates. This faunal succession evidences almost continuous occupation of southern high-palaeolatitude seas, and repeated endemic diversifications (including nascent members of some key lineages) amongst emigrant cosmopolitan clades. The primary dispersal routes are likely to have been peri-Gondwanan, with coastal migrations along the western Tethys and polar margins of the Panthalassan Ocean. However, augmentation by increasing continental fragmentation and seaway corridor connectivity probably occurred from the Middle Jurassic to Late Cretaceous. Latest Cretaceous mosasaurid and elasmosaurid taxa also reveal regional affinities with the emergent western Pacific and Weddellian austral bioprovinces. The extreme rarity, or complete absence, of many major groups prevalent elsewhere in Gondwana (e.g., tanystropheids, Triassic sauropterygians, bothremydid marine turtles, thalattosuchians and dyrosaurid crocodylomorphs) is conspicuous, and might be related to stratigraphical/collecting biases, or the predominantly higher-palaeolatitude, cooler-water Mesozoic palaeogeography of the Australasian region. Although the burgeoning record is substantial, much still awaits discovery and adequate documentation; thus Australasia is still one of the most exciting prospects for future insights into the global history of Mesozoic marine tetrapods. Benjamin P. Kear* [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyvägen 16, SE-752 36 Uppsala, Sweden; R. Ewan Fordyce [ewan.fordyce@otago.ac.nz] Department of Geology, University of Otago, Post Box 56, Dunedin 9054, New Zealand; Norton Hiller [norton.hiller@gmail.com] Canterbury Museum, Rolleston Avenue, Christchurch 8013, New Zealand; Mikael Siversson [mikael.siversson@museum.wa.gov.au] Western Australian Museum, 49 Kew Street, Welshpool, Western Australia 6106.

New plesiosaurian specimens (Reptilia, Plesiosauria) from the Upper Cretaceous (Turonian) of Goulmima (Southern Morocco)

Article

Sep 2017

Two new plesiosaurian specimens coming from lower Turonian deposits of Goulmima in Morocco are described. The three-dimensional digital reconstructions of both specimens provide details about their skull roof, mandible and atlas-axis complex. In addition, computed tomography allows to reconstruct their braincase, which is a part of the skull poorly known among plesiosaurians due to either poor preservation and/or insufficient preparation, but that offers a large number of characters used in phylogenetical analyses. After descriptions and comparisons, the two specimens D1-8213 and MNHN F-GOU14 are assigned to Libonectes morgani and to an undetermined Polycotylidae, respectively. The presence of the North American taxon Libonectes morgani in the deposits of Goulmima confirms a trans-Atlantic faunal connectivity at that time and that Elasmosauridae were able to exploit the open marine environment for dispersion. Polycotylids have already been described from Goulmima; however, the typical preservation of these specimens in nodules prevented their preparation and the access to their internal anatomy. Here, the use of X-ray computed tomography shows the strong interest to use such a technique and provide new anatomical details.

The Mesozoic butterfly effect or evolution that never happened

Article

Full-text available

May 2017

Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians

Article

Full-text available

Feb 2017
PLOS ONE

Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing ‘fangs’. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2–3 years–other polyphyodont amniotes normally take ~1–2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation.

Review of two marine vertebrate assemblages from the Arauco Basin (central Chile) reveals diversity changes throughout the Maastrichtian

Article

Aug 2024
CRETACEOUS RES

Rodrigo A. Otero

Upper Cretaceous vertebrate records from Chile are mostly known by historical mentions with unknown repositories and uncertain stratigraphic provenance. This contribution reviews and complements two marine vertebrate assemblages from the Upper Cretaceous of central Chile, which were part of the ancient Arauco Basin. The oldest assemblage (lower Maastrichtian) comprises abundant condrichthyans referred to Carcharias gracilis, Odontaspis cf. winkleri, Scapanorhynchus sp., Centrophoroides appendiculatus, Squatina sp., Cretorectolobus sp., Orectolobidae indet., Paraorthacodus sp., Ischyrhiza chilensis and Biropristis landbecki, which adds to the previously reported ocurrences of Echinorhinus sp. and Myledaphus araucanus. In addition, chimeroids referred to as Edaphodon kawai and remains of a leatherback turtle referable to Mesodermochelys sp. are here described, the latter being its first occurrence outside Japan. The younger assemblage (upper Maastrichtian) includes similar chondrichthyans and a higher diversity of marine reptiles, including plesiosaurians (Aristonectes sp., Aristonectinae indet., and Elasmosauridae indet.), sea turtles (Pancheloniidae indet.) and diverse mosasaurs (Halisaurus sp., Tylosaurinae indet., and the first local occurrence of Plioplatecarpinae indet.). Throughout the Maastrichtian, the local marine vertebrates likely suffered a declination in abundance but a rise in diversity, with evidence of a marked alteration in middle levels of the trophic web during the upper Maastricthtian. The studied material allows a better understanding of the Upper Cretaceous vertebrate marine fauna in lower latitudes of the southeastern Pacific.

Reappraisal of the first historical record of Aristonectes Cabrera, 1941 (Elasmosauridae, Aristonectinae) from the Upper Cretaceous of central Chile

Article

Dec 2023
CRETACEOUS RES

Rodrigo A. Otero

This contribution reassesses the first historical specimen from the Upper Cretaceous of Chile, referred to the genus Aristonectes in the late sixties. A detailed description allows an improved understanding of those elements comprising the mandibular ramus. These are found to be coincident with those of the holotype of Aristonectes quiriquinensis, with only minor differences in size, which are explainable due to different ontogenetic stages of the specimens. Therefore, the re-studied material is now referred to as A. quiriquinensis, being the second available skull material of the species. The new description recognizes that the available elements belong to the right side of the skull. Moreover, the material also preserves part of the right orbit, a portion previously unknown in the available skulls of Aristonectes spp. The assessed orbit outline reveals the presence of the prefrontal, forming the anteroventral margin of the orbit. A similar topology is observed in other aristonectines such as Morturneria seymourensis and Kaiwhekea katiki, but also in the non-aristonectine austral elasmosaurid Tuarangisaurus keyesi. The orbit outline of Aristonectes quiriquinensis is here disclosed for the first time, showing this to be remarkably similar to that of Kaiwhekea, but probably differs from that of Aristonectes parvidens, at least based in their available skull elements. This suggests that A. quiriquinensis could be a more basal taxon with respect to A. parvidens.

Occurrence of Styxosaurus (Sauropterygia: Plesiosauria) in the Cenomanian: implications for relationships of elasmosaurids of the Western Interior Seaway

Article

Aug 2023

Revision of the short-necked Cretaceous plesiosaurians from New Zealand

Article

Full-text available

Mar 2023

Polycotylidae Cope, 1869 is a clade of short-necked plesiosaurians that achieved a cosmopolitan distribution by the Late Cretaceous. Here, the material previously referred to Polycotylidae/Pliosauridae from the Upper Cretaceous of New Zealand is reviewed, concluding that only 2.4% and 7.7% respectively of the total plesiosaurians specimens recovered in these formations (late Campanian-early Maastrichtian Tahora Formation and Campanian-Maastrichtian Conway Formation) belong to Polycotylidae. This proportion is similar to that recorded in upper Campanian-Maastrichtian levels of the Allen, Los Alamitos and La Colonia formations, northern Patagonia (Argentina) and southernmost Chile, but contrasts with the coeval absence of polycotylids in Campanian-Santonian levels of Antarctica and central Chile. These new results improve our knowledge about the representation of Weddellian polycotylids and underline the relative scarcity of Campanian-Maastrichtian records in the Weddellian Province.

Late Campanian-Early Maastrichtian Vertebrates From The James Ross Basin, West Antarctica: Updated Synthesis, Biostratigraphy, And Paleobiogeography

Article

Full-text available

Jun 2022
AN ACAD BRAS CIENC

The Snow Hill Island Formation (SHIF; late Campanian-early Maastrichtian) crops out in the northeast of the Antarctic Peninsula and constitutes the basal part of the late Campanian-early Maastrichtian sedimentary succession of the James Ross Basin (NG Sequence). Its major exposures occur at the James Ross and Vega islands. Several fossil-bearing localities have been identifi ed in the SHIF providing a valuable fauna of invertebrates and vertebrates, and fl ora. Our study focuses on the vertebrate fauna recovered at Gamma and Cape Lamb members of the SHIF. The marine vertebrate assemblages include chondrichthyans, actinopterygians, and marine reptiles (elasmosaurid plesiosaurs and mosasaurs). A diverse terrestrial vertebrate as semblage has been reported being characterized by dinosaurs (sauropod, elasmarian ornithopods, nodosaurid ankylosaur, and a paravian theropod), pterosaurs and birds. Most SHIF dinosaurs share close affi nities with penecontemporaneous taxa from southern South America, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the Late Cretaceous. The Snow Hill Island Formation provides the most diverse Late Cretaceous marine and continental faunas from Antarctica. The present study summarizes previous and new vertebrate fi ndings with the best actualized stratigraphical framework, providing a more complete fauna association and analyzing further perspectives.

New freshwater plesiosaurian materials from the Middle Jurassic Xintiangou Formation of the Sichuan Basin, southwestern China

Article

Full-text available

Aug 2020

Sichuan Basin is very famous for the Mesozoic reptiles, especially the Jurassic dinosaurs. Here, we report some isolated plesiosaurian teeth and vertebrae newly excavated from the Middle Jurassic Xintiangou Formation in Yunyang county, Chongqing City, the northeastern region of the Sichuan Basin, southwestern China. The specimens are referred to Pliosauroidea based on the combination of the following features: the circular cross-section of the tooth crown, apicobasal ridges fully covering the enamel surface and reaching to the apex, the short and amphicoelous centrum, the centrum shorter than wide or tall, and the absence of a keel on the lateral surface of the cervical centrum. With the fragmentary nature, it is undetermined whether the Yunyang specimens belong to a known taxon or represent a new species of Plesiosauria. These plesiosaurian specimens further demonstrate that the freshwater plesiosaurians are common in the Jurassic deposits of the Sichuan Basin. For a comprehensive knowledge of the plesiosaurians of the basin in origin, distribution and diversity, to discover new and more complete specimens is necessarily the first priority.

A New Plesiosaur (Reptilia: Sauropterygia) Specimen from the Upper Cretaceous of West Antarctica, with Comments on the Ontogeny and Morphological Diversity of the Elasmosaurid Pelvic Girdle

Article

Full-text available

Jul 2020

Although knowledge of Mesozoic marine reptiles from Antarctica has improved considerably in recent years, associated and well-preserved skeletal material of these animals remains uncommon. Here we describe a largely complete, closely associated plesiosaur pelvic girdle recovered from the uppermost Cretaceous (Maastrichtian) Sandwich Bluff Member of the López de Bertodano Formation of Vega Island, in the James Ross Basin of the northernmost Antarctic Peninsula. The new specimen exhibits characters that allow its referral to Elasmosauridae, but its incompleteness precludes a more precise taxonomic determination. Ontogenetically variable and systematically useful features of the elasmosaurid pelvis are reviewed and discussed. The new specimen improves knowledge of Southern Hemisphere elasmosaurids just prior to the K/Pg extinction event.

Endocranial microtomographic study of marine reptiles (Plesiosauria and Mosasauroidea) from the Turonian (Late Cretaceous) of Morocco : palaeobiological and behavioral implications

Thesis

Nov 2017

Rémi Allemand

As windows into the deep history of neuroanatomy, endocasts may provide information about the central nervous system of fossil taxa. Based on exceptionally preserved specimens of coeval mosasauroids (Squamata) and plesiosaurians (Sauropterygia), from the Turonian outcrops of Goulmima (Southern Morocco), the aim of this work was to describe for the first time in detail the endocranial anatomy of these two major clades of Mesozoic marine reptiles to provide insights about their sensory abilities, and thus to understand their cohabitation, interactions and niche partitioning. The endocranial anatomy of related extant squamates, mainly snakes but also varanids and amphisbaenians, also almost unknown until now, has been performed for the first time and used for comparative purpose to analyze the form-function relationships associated to endocasts. The analysis of the endocranial variability in extant squamates pointed out that endocasts reflect both phylogenetic and ecological signals, and that the relative size of each endocranial structure can be used to reveal differences in vision and olfaction according to taxa. Among fossil taxa, computed tomography was used to reconstruct in detail the cranial morphology of three unpublished specimens of Plesiosauria. These specimens have been examined and described, two have been referred to the elasmosaurid Libonectes morgani and the third one is an indeterminate polycotylid. The 3D morphology of the endocast has been reconstructed for these plesiosaurian specimens and the basal mosasauroid Tethysaurus nopcsai. The results show that the endocranial morphology of Plesiosauria differs from that know in other extinct and extant vertebrates. Based on the relative size of the structures composing their endocasts, both the mosasauroid Tethysaurus and the plesiosaurians seem to rely more on vision than on olfaction to interact with their environment. However, these new endocast data, added to information already available in the literature suggest different modes of locomotion and hunting techniques, which probably allowed them to coexist in Goulmima as quaternary consumers.

Neck mobility in the Jurassic plesiosaur Cryptoclidus eurymerus: Finite element analysis as a new approach to understanding the cervical skeleton in fossil vertebrates

Article

Full-text available

Nov 2019

The sauropterygian clade Plesiosauria arose in the Late Triassic and survived to the very end of the Cretaceous. Plesiosauria evolved the greatest species diversity of any marine reptile clade, attaining a global distribution. Plesiosauria consist of two clades, Rhomaleosauridae and Neoplesiosauria. Basal Neoplesiosauria have long necks with at least 30 cervicals, but show qualitative osteological evidence for a stiff neck. Here we quantify neck mobility in lateral, ventral, and dorsal directions based on finite element modeling of neck vertebrae from the Middle Jurassic plesiosaur Cryptoclidus eurymerus . We model the mobility in a single motion segment, consisting of two adjacent cervical vertebrae and the joints connecting them. Based on the model with a maximum intervertebral spacing of 3 mm, we find that in Cryptoclidus , the maximum angle of lateral deflection in the motion segment was 2°. The maximum angle of ventral deflection was 5° and of dorsal deflection was 5°. When these values are multiplied by the number of cervical vertebrae, it becomes apparent that neck mobility was limited in all directions. The maximum angle of total lateral deflection in the neck was 67°. The maximum angle of total ventral deflection was 148° and of total dorsal deflection was 157°. This raises the question of the function of such a long, multi-segment but immobile neck. We posit that the long neck served in hydrodynamic and visual camouflage, hiding the bulk of the body from the small but abundant prey, such as schooling fish and squid. Neck immobility may have been advantageous in withstanding strong hydrodynamic forces acting on the neck during predatory strikes.

A new late Aptian elasmosaurid from the Paja Formation, Villa de Leiva, Colombia

Article

Feb 2019

A new genus and species of elasmosaurid, Leivanectes bernardoi gen. et sp. nov., from the upper Aptian levels of the Paja Formation of Villa de Leiva (Boyacá Colombia) is described. The new elasmosaurid is characterized by a short mandibular symphysis, bears only three alveoli (there are five in Callawayasaurus colombiensis), has an enlarged premaxillary alveoli, and has a mandible that includes only seven alveoli in each ramus anterior to the orbit (there are 11 in Callawayasaurus colombiensis). This new elasmosaurid taxon has fewer and larger alveoli than any other presently described elasmosaurid taxon. The observed differences indicate that the new species consumed larger-bodied prey than did other elasmosaurids. The new taxon suggests that the elasmosaurids were diverse in the Colombian late Aptian sea.

Osteology of Rhomaleosaurus Thorntoni (Sauropterygia: Rhomaleosauridae) from the Lower Jurassic (Toarcian) of Northamptonshire, England

Article

Oct 2014

This paper describes the holotype of Rhomaleosaurus thorntoni (NHMUK PV R4853) from the upper part of the Whitby Mudstone Formation (Toarcian) of Kingsthorpe Hollow, Northamptonshire, England. Rhomaleosaurus thorntoni possesses the following autapomorphies: (1) dorsomedian foramen with mediolaterally narrow slit-like morphology situated well anterior to the external nares; (2) humerus long relative to skull length and body length; (3) distal end of humerus greatly expanded both preaxially and postaxially. Several other characters present in Rhomaleosaurus thorntoni cannot be determined in other Rhomaleosaurus species, so these may also be autapomorphies of R. thorntoni. A summary of previous phylogenetic analyses of Plesiosauria shows that the relationships among the three main clades (Rhomaleosauridae, Pliosauridae, Plesiosauroidea) are unclear and further investigation is required to understand the evolution of early plesiosaurians.

FIRST CRANIAL REMAINS OF A NON-ARISTONECTINE ELASMOSAURID PLESIOSAUR FROM ANTARCTICA

Conference Paper

Full-text available

Oct 2017

Elasmosaurid plesiosaurs remains are frequently collected across the Marambio Group (Santonian-Danian), Antarctica. Notwithstanding, finding of informative cranial material is extremelyrare. A new specimen (MLP 15-I-7-6), from the Cape Lamb Member of the Snow Hill Island Formation (lower Maastrichtian) in Vega Island (Fig. 1.A, B) allows studyingthe cranial anatomy of Antarctic non-aristonectine elasmosaurids. The preserved parts of the specimencomprisesthebraincase,thesquamosal archand theposteriorhalf ofthepalate, all enclose in a single sandstone concretion and associated with cervical, dorsal and caudal vertebrae, and fragmentary girdles and propodials (Fig. 1C). The elongated vertebral centra indicate that MLP 15-I-7-6 is not an aristonectine elasmosaurid. However it shows two features previously recorded only in the aristonectine elasmosaurids Aristonectes quiriquinensis and A. zealandiensis and therefore, considered synapomorphics for that clade (Oteroetal.,2014,2016):absenceofposteriorinterpterygoid,andthepresenceofaposterior plate-like extension of the pterygoid (Fig. 2, 3). This suggests that such features could not be exclusive of the aristonectine clade. This new record is important because it shows, for the first time, differences between the skull of non-aristonectine elasmosaurids from the Weddellian Province (i.e. Patagonia, Western Antarctica and New Zealand) and those from the Northern Hemisphere. The authors thank to Dirección Nacional del Antártico and the Instituto Antártico Argentino, project: PICTO 2010-0093 (M.R.) and support of the Fuerza Aérea Argentina (Base Marambio, Dotación 46°).

A new elasmosaurid (Sauropterygia, Plesiosauria) from the Bearpaw Shale (Late Cretaceous, Maastrichtian) of Montana demonstrates multiple evolutionary reductions of neck length within Elasmosauridae

Article

Apr 2017

Plesiosauria is a diverse clade of marine reptiles that have been studied since the early 19th century. However, phylogenetic relationships within the group have been contentious due to limited taxon sampling and a misunderstanding of how ontogeny and interspecific and intraspecific variation affect character states. This is particularly true for elasmosaurids, a Cretaceous clade of long-necked plesiosaurians. In 2010, a new, nearly complete skeleton, MOR 3072, was collected from the Late Cretaceous (Campanian–Maastrichtian) Bearpaw Shale of northeast Montana. The specimen provides detailed morphological information rarely observed within Elasmosauridae, including a complete skull, the anterior 23 cervical vertebrae, a partial dorsal and caudal vertebral column, incomplete pectoral and pelvic girdles, elements of both fore- and hind limbs, ribs, and gastralia. Being early Maastrichtian in age, MOR 3072 is the stratigraphically youngest elasmosaurid known from the Western Interior Seaway and is recognized as a new genus and species, Nakonanectes bradti. We present a description of Nakonanectes bradti and conduct an extended phylogenetic analysis of Elasmosauridae. N. bradti is found to be deeply nested within the clade of large-bodied, long-necked, Western Interior Styxosaurinae. However, MOR 3072 is one of the smallest adult elasmosaurids ever recovered (5.1–5.6 m) and exhibits a reduced neck length compared with other North American elasmosaurids, resulting from a reduction in both centrum length and number of cervical vertebrae (39–42 were originally present). These features are convergent with the Southern Hemisphere clade of short-necked Maastrichtian elasmosaurids, Aristonectinae, and demonstrate multiple origins of short-necked body proportions from longer-necked ancestors within Elasmosauridae. http://zoobank.org/urn:lsid:zoobank.org:pub:85731F4A-EA70-4C9A-B595-792EDBC096C0 SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Serratos, D. J., P. Druckenmiller, and R. B. J. Benson. 2017. A new elasmosaurid (Sauropterygia, Plesiosauria) from the Bearpaw Shale (Late Cretaceous, Maastrichtian) of Montana demonstrates multiple evolutionary reductions of neck length within Elasmosauridae. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1278608.

Comparative Cranial Anatomy of Two North American Cretaceous Plesiosaurs

Article

Full-text available

Dec 1997

Kenneth Carpenter

This chapter presents comparative cranial anatomy of two North American cretaceous Plesiosaurs. The skulls of Elasmosaurus morgani and Dolichorhynchops osborni are compared as representatives of the Cretaceous plesiosaur families Elasmosauridae and Polycotylidae, respectively. Cranial features and the atlas-axis complex appear to be more stable evolutionarily than postcranial features. Similarities indicate that the short-necked Cretaceous polycotylids are the sister group to long-necked elasmosaurids. This implies that the short-necked polycotylids of the Cretaceous are not descended from the short-necked pliosaurs of the Jurassic. The chapter further elaborated the significance of similarities between Libonectes and Dolichorhynchops. The short neck has appeared independently at least twice in the Plesiosauria, and the term "pliosaur" to refer any short-necked plesiosaur should be abandoned to avoid any phyletic implications. Differences between Elasmosaurus morgani and Elasmosaurus platyurus demonstrate that the two species belong to a different genera and a new name is proposed for E. morgani.

Large eyeballs in diving ichthyosaurs—The huge eyes of these extinct reptiles may have been useful deep in the ocean

Article

Full-text available

Dec 1999

The huge eyes of these extinct reptiles may have been useful deep in the ocean.

Function and phylogeny in Sauropterygian (Diapsida) evolution

Article

Full-text available

Jan 1993

Glenn Storrs

The Sauropterygia includes the Pachypleurosauria and Nothosauriformes. The nothosauriforms are here defined as the Plesiosauria, Placodontia, and relatively plesiomorphic taxa historically known as "nothosaurids'. The functional evolution of the Sauropterygia was dominated by locomotor adaptations for an aqueous environment. The physics of buoyancy and hydrodynamics were the primary mitigating factors. Ancestral history of the clade constrained most of its representatives to limb-dominated (paraxial) propulsion, after this format was adopted by early sauropterygians. "Nothosaurid' locomotion, deriving drag and lift thrust from the limbs, was functionally antecedent to the plesiosaur swimming style. Pleisosaurs used all four limbs, perhpas simultaneously, to generate a large component of lift-based thrust. For reptiles, this was an unusual functional response to a secondary invasion of the sea. -from Author

New plesiosaurs from the Upper Cretaceous of Antarctica

Article

Full-text available

Oct 1989

New plesiosaur remains from the Upper Cretaceous Lopez de Bertodano Formation (late Campanian-Maastrichtian) of Seymour Island, Antarctic Peninsula include Cryptoclididae and Elasmosauridae. The occurrence of Cryptoclididae is reported from the Antarctic region for the first time. The taxon represents a new genus and species, based on a skull and associated cervical vertebrae. The long, slender and delicate teeth may have formed a ‘trapping’ device that enabled cryptoclidids to feed on small fish and crustaceans that abound in the same deposits. The cryptoclidids had a restricted distribution, being known so far from the Middle and Late Jurassic of England, and the Late Cretaceous of Chile, Argentina, and Antarctica. Other specimens, represented by several postcranial skeletons, are taxonomically indeterminate, but they share some features with other contemporary elasmosaurid genera such as Hydrotherosaurus, Morenosaurus, Thalassomedon , and Mauisaurus . Unlike the cryptoclidids, the elasmosaurids had a cosmopolitan distribution during the Jurassic and Cretaceous periods. Trophic diversity within guilds of marine predators is examined in the Lopez de Bertodano palaeocommunities. Three predator guilds are recognized on the basis of tooth morphology and prey preference. The mosasaurs composed the ‘Cut guild’, and were the principal predators. The elasmosaurids constituted the ‘Pierce guild’, and the cryptoclidids formed the ‘Trap guild’. These marine reptiles exploited the various pelagic resources such as sharks, bony fish, soft cephalopods and crustaceans, and survived until the end of the Cretaceous. The plesiosaurs were excellent swimmers, and used their hyperphalangic paddles for subaqueous flight in the manner of modern sea lions.

Swimming capabilities of Mesozoic marine reptiles: a review

Chapter

Sep 1994

Judy Massare

THIS IS AN UPDATE OF THE 1988 PAPER Mesozoic marine reptiles had a range of swimming abilities. Jurassic and Cretaceous ichthyosaurs, with their deep, streamlined body, narrow caudal peduncle, and lunate tail, were probably efficient, fast sustained swimmers. The elongated bodies and long, broad tails of the early ichthyosaurs and mosasaurs (and marine crocodiles) suggest that they were adapted for rapid acceleration and were probably ambush predators. More problematic are the plesiosaurs, which utilized subaqueous flight using two pairs of wing-shaped appendages. The long-necked plesiosauroids were probably slow swimmers and relied on a sneak attack to capture prey. The pliosauroids, with shorter necks, more compact bodies, and larger, broader limbs were probably faster swimmers than the plesiosauroids. By estimating the total drag and the amount of energy available for locomotion, relative sustained swimming capabilities can be estimated for reptiles of the same mass but different body forms. Calculations suggest that ichthyosaurs were faster than either plesiosaurs or mosasaurs, and plesiosaurs were slightly faster than mosasaurs. If the results are scaled to body length rather than mass, the differences in sustained swimming speeds are even more pronounced. Differences arise from estimates of hydrodynamic efficiency, shape, and metabolic rate for each kind of reptile, the latter being the most important factor.

The lithostratigraphy of Late Cretaceous to Early Pleistocene rocks of northern Canterbury, New Zealand

Article

Jan 1985

The geology of the lower shag valley, n.E. Otago

Article

O.D. Paterson

On the remains of a plesiosaurian reptile (Plesiosaurus australis) from the Oolitic Formation in the Middle Island of New Zealand

Article

R. Owen

On the Remains of a Plesiosaurian Reptile (Plesiosaurus Australis) from the Oolitic Formation in the Middle Island of New Zealand

Article

R. Owen

Stratigraphy and structure of the Te Hoe-Waiau River area, western Hawkes Bay

Article

Jan 1987

Phillip R Moore

A Late Cretaceous near-shore rocky substrate macrofauna from northern Hawkes Bay, New Zealand

Article

Jan 1988

J.S. Crampton

Un Plesiosaurio nuevo del Cretáceo del Chubut

Article

Jan 1941

A. Cabrera

La presencia en Chile de Aristonectes Cabrera (Plesiosauria), del Maestrichtense del Chubut, Argentina. Edad y carácter de la transgresión Rocanense

Article

Jan 1969

R. Casamiquela

The English Late Jurassic Plesiosauroidea (Reptilia) and review of the phylogeny and classification of the Plesiosauria

Article

Jan 1981

D.S. Brown

The Piripauan and Haumurian stratotypes (Mata Series, Upper Cretaceous) and correlative sequences in the Haumuri Bluff district, South Marlborough

Article

Jan 1978

A taphonomic and diagenetic case study of a partially articulated ichthyosaur

Article

Jan 1987

David Martill

New Zealand Late Jurassic to Eocene dinoflagellate biostratigraphy - A summary

Article

Jan 1984
NEWSL STRATIGR

G.J. Wilson

Elasmosaurid plesiosaurs with description of new material from California and Colorado

Article

Jan 1943

S.P. Welles

Biogeographic significance of the Late Mesozoic and Early Tertiary molluscan faunas of Seymour Island ( Antarctic peninsula) to the final breakup of Gondwanaland.

Article

Jan 1979

William J. Zinsmeister

The last fragmentation of Gondwanaland occurred during the Late Cretaceous and early Paleogene. During the initial part of this phase, the various continents were separated by shallow seas. The similarities of the Late Cretaceous and early Paleogene molluscan faunas indicate that the region represented a single, broad, continuous faunal province. This shallow-water marine province which extended from W. Antarctica into both southern S. America and E. Australia is here designated the Weddellian Province. The Eocene molluscan fauna of Seymour Island provides new data indicating that the increased faunal provincialism in the S. Hemisphere during the Tertiary coincides with the final breakup and separation of Gondwanaland. -from Author

New mosasaurs (Reptilia; Family Mosasauridae) from the Upper Cretaceous of North Island, New Zealand

Article

Jan 1990

J. Wiffen

New mosasaur specimens of Piripauan-Haumurian (Campanian-Maastrichtian) age are described from the Mangahouanga Stream, North Island, New Zealand. These include two distinctive adult skulls and one incomplete cranial and postcranial specimen. A new genus and species Rikisaurus tehoensis is recognised and a new species of Mosasaurus, M.flemingi, is described. A further specimen is identified as aff. Prognathodon overtoni. Two fragmentary specimens are also described (as aff. Moanasaurus mangahouangae and gen. and sp. indet.), along with an isolated adult limb bone (gen. and sp. indet.) of a type not previously collected in New Zealand.

The first Late Cretaceous turtles from New Zealand

Article

Mar 1981

J. Wiffen

The presence of turtles in the Upper Cretaceous rocks of New Zealand is indicated by the recent discovery of several disarticulated plastron and carapace fragments. These bones, of Piripauan-Haumurian age (Campanian-Maastrichtian|Late Cretaceous), are identified as Protostegidae sp. indet. and appear to be the first record of this family in the southern hemisphere.

Moanasaurus, a new genus of marine reptile (Family Mosasauridae) from the Upper Cretaceous of North Island, New Zealand

Article

Jul 1980

J. Wiffen

A new genus and species of mosasaur, Moanasaurus mangahouangae of Piripauan-Haumurian age (Campanian-Maastrichtian) is described from the North Island, New Zealand. The remains upon which the new genus and species is based (disarticulated skull, teeth, vertebrae, paddle elements, and rib fragments) are sufficiently distinct to enable it to be distinguished from previously described taxa.

XLVII.—On some new Plesiosauria from the Oxford Clay of Peterborough

Article

Jan 1909

C. W. Andrews

The Nature of the Shoulder Girdle and Clavicular Arch in Sauropterygia

Article

Nov 1891
Proc Roy Soc Lond

H. G. Seeley

The Sauropterygia and Ichthyosauria having formerly been combined in the group termed Nexipoda or Enaliosauria, it has been rather assumed than proved that the bones which form the shoulder girdle in those orders are homologous. The Ichthyosaurian shoulder girdle was well figured by Sir E. Home (‘Phil. Trans.,’ 1818, Part I) and Cuvier (‘Oss. Foss.,’ PI. 258). Figures by other authors agree substantially (Huxley, ‘Anatomy of Vertebrates,’ p. 244) in showing (1) that the coracoids meet ventrally in the median line; (2) that there is a notch on the anterior margin of the coracoid between the median anterior cartilaginous border of the bone and the scapula, and this notch varies in depth and width with the species; (3) the scapula is directed outward, upward, and forward; (4) its articular end has a posterior part which contributes with the coracoid to form the glenoid cavity for the head of the humerus, a median part, which articulates with the anterior articular edge of the coracoid, and an anterior surface, which does not differ in its cartilaginous articular aspect or thickness from the middle portion, but which looks inward without any bony element of the shoulder girdle to articulate with it. This condition has not been explained.

The origin of the Southern Ocean marine fauna

Article

Oct 1989

Current knowledge of the break-up of Gondwana during the Tertiary indicates that shallow water marine habitats may have been present continuously, and on occasions were considerably more extensive than at present. Although direct fossil evidence is sparse after the Eocene, geophysical evidence suggests that shallow waters have been present since the late Mesozoic, and possibly much longer. The break-up of Gondwana was accompanied by a more or less steady lowering of both surface and bottom temperatures in the Southern Ocean from about 15°C in the Late Cretaceous to the present range of roughly +2 to -1.8°C. Microfossils in deep-sea drilling cores indicate that temperature drops were particularly sharp in the early Oligocene (c. 38 Ma), mid-Miocene (10-14 Ma) and Pliocene (c. 4 Ma BP). Geological evidence suggests that the Drake Passage opened, and the present oceanographic regime established, about 25-30 Ma BP. This is now known to be about the time of full-scale development of the East Antarctic ice cap. Subsequently ice sheets extended across, and deeply eroded, the continental shelves but the effects of these glacial maxima on the marine biota are not fully understood. Late Cretaceous/early Tertiary marine fossils from the James Ross Island group indicate a diverse shallow water marine fauna, including two groups notably lacking in diversity in the living fauna: decapods and teleost fish. In several genera occurrences in this fauna predate first occurrences in lower latitudes by as much as 40 Ma, suggesting the possibility that a number of groups originated at high southern latitudes. The living fauna exhibits a high biomass in many areas, and within-site diversity can be as high as anywhere in the world. Some individual taxonomic groups, however, (notably bivalves and gastropods) have a lower diversity than in the tropics, supporting the concept of a latitudinal cline in diversity. Studies of physiological adaptation to temperature suggest that the decline in seawater temperature during the Cenozoic has not presented a particularly severe evolutionary problem. The reasons for the absence of large decapods and the low diversity of fish in the present fauna are unclear. Most of the biological features of the modern fauna are more likely a response to the seasonality of the ecosystem rather than low temperature per se. Overall the evidence suggests that the present Southern Ocean shallow water marine fauna largely evolved in situ, having been present since at least the Late Cretaceous, and possibly much longer. Some groups have invaded, for example along the Scotia arc, but the isolation of the Southern Ocean by the present oceanographic regime and the limited dispersal ability of many forms means that exchange with lower latitudes is very slow.

Revision of the Piripauan and Haumurian local stages and correlation of the Santonian‐Maastrichtian (Late Cretaceous) in New Zealand

Article

Sep 2000

The uppermost Cretaceous in New Zealand is represented by the local Mata Series, composed of the Piripauan and overlying Haumurian Stages. The existing definitions and subdivision of these stages, and the type section at Haumuri Bluff, southeastern Marlborough, are wholly inadequate. To address these problems, three key sections in southeastern Marlborough have been studied in detail: a tributary of Ben More Stream, the headwaters of Kekerengu River, and a railway cutting at the mouth of Conway River. All three sections have yielded rich palynomorph assemblages and the first two contain inoceramid bivalves and foraminiferal faunas. In addition, magnetostratigraphic data have been obtained from the Ben More Stream section.We propose to revise the Piripauan and Haumurian Stages from new boundary stratotypes in the Ben More Stream section. The Piripauan is defined at the lowest occurrence of the inoceramid /. pacificus. The base of the Haumurian Stage is defined at the lowest occurrence of the dinoflagellate Nelsoniella aceras. In addition, we propose to subdivide the Haumurian into formal Lower and Upper substages; the base of the Upper Haumurian is defined at the lowest occurrence of the dinoflagellate Isabelidinium pellucidum in a boundary stratotype in the Conway River railway cutting. These boundary criteria can be correlated widely within New Zealand across a broad range of marine facies. The Piripauan contains two inoceramid and three dinoflagellate zones. The Haumurian contains six dinoflagellate zones and five subzones. Based on biostratigraphic and magnetostratigraphic data, the Piripauan/Haumurian boundary is correlated with the C34‐C33 magnetochron boundary and with the middle‐upper Santonian boundary. The Piripauan and Haumurian Stages thus have durations of c. 1.7 and 19.5 m.y., respectively.In terms of content, these revisions largely preserve the stages as used previously in New Zealand and require no significant changes to existing geological maps.

An Upper Cretaceous Ornithopod from New Zealand

Article

Dec 1989
Geobios

The partial ilium of a Dryosaurus--like ornithopod dinosaurhas been discovered in the Upper Cretaceous Maungataniwha Sandstone of North Island, New Zealand. This is the first ornithischian dinosaur from New Zealand. At the time this animal lived, New Zealand was near the Ross Sea region of Antarctica, near 60 degrees S. latitude. This occurrence suggests such dinosaurs were capable of living in polar regions and may have lived in Antarctica itself.RésuméL'ilion partiel du Dryosaurus semblable à celui d'un dinosaurienornithopode a été découvert dans les grès Maungataniwha du Crétacé supérieur de l'île du Nord de la Nouvelle-Zélande. C'est le premier dinausaurien ornithischien de Nouvelle-Zélande. A l'époque à laquelle cet animal a vécu, la Nouvelle-Zélande était la mer de Ross dans la région Antarctique, à peu près à la latitude de 60 degrés Sud. Cette présence suggère que des dinosauriens semblables étaient susceptibles de vivre dans des régions polaires et ont peut-être même vécu en Antarctique.

Cretaceous and Cenozoic sedimentary basins and geological evolution of the Canterbury region

Article

Jan 1989

First pterosaur from New Zealand

Article

Jan 1988

The distal portion of the left ulna of a pterosaur has been discovered in Upper Cretaceous marine sediments in New Zealand. This is the first evidence of a pterosaur from New Zealand, the third from the Late Cretaceous of the southern hemisphere, and represents the extreme southern occurrence of a pterosaur. It is not referable to any described taxon known from comparable material.

A new Elasmosaurid plesiosaur from the Lower Jurassic of southern France

Article

Oct 1999
Palaeontology

Plesiosaurus tournemirensis Sciau, Crochet and Mattei, based on a nearly complete skeleton with skull from the Upper Toarcian (Lower Jurassic) of Tournemire (Aveyron Department, southern France), is here redescribed and reinterpreted. Comparisons with other plesiosaurs indicate that it belongs to a new genus, Occitanosaurus. O. tournemirensis is characterized mainly by its spatulate premaxillae with short facial process, very high postorbital broadly contacting posterior ramus of the maxilla, trapezoidal jugal excluded from orbital margin, orbit diagonally oriented, temporal fenestra with a sigmoidal anterior margin, 43 cervical vertebrae, powerful interclavicle-clavicle complex and coracoids with a pointed protuberance on lateral border and expanded posterolateral cornua. Cranial and cervical vertebra features show that this new genus is undoubtedly a representative of the Elasmosauridae. A preliminary cladistic analysis of long-necked plesiosaurs reveals that, within Elasmosauridae, Occitanosaurus is a close relative of Microcleidus and Muraenosaurus.

The Fossil Record 2

Article

Jan 1993

Michael J Benton

Functional Anatomy of the Head of the Large Aquatic Predator Rhomaleosaurus zetlandicus (Plesiosauria, Reptilia) from the Toarcian (Lower Jurassic) of Yorkshire, England

Article

Feb 1992

Michael Alan Taylor

The skull and mandible of the type specimen of the large pliosauroid plesiosaur Rhomaleosaurus zetlandicus from the Toarcian of England are elongate, and adapted for powerful predatory activity in water. The broadly caniniform dentition suggests that Rhomaleosaurus fed on a wide range of active prey, and forcibly dismembered larger prey by shaking and twisting them. The cranial musculature is reconstructed for the first time in plesiosaurs. It was adapted for feeding in water. Gross form, shape of constituent bones, and sutural morphology confirm adaptations to resist great bending moments arising from the action of the muscles when biting on prey. Rhomaleosaurus was a visual predator. The eyes were large. The stapes is present. Underwater olfaction was likely. The structure of the head of Rhomaleosaurus is a functional compromise between the needs to maximize structural strength and to maximize swimming and feeding efficiency. -from Author

Cranial Anatomy of the Lower Jurassic Pliosaur Rhomaleosaurus megacephalus (Stutchbury) (Reptilia: Plesiosauria)

Article

Feb 1994

Arthur R.I. Cruickshank

An account is given of the skull of a large pliosauroid plesiosaur from the lowermost Hettangian (Lower Lias; Lower Jurassic) of Barrow upon Soar, Leicestershire, identified as Rhomaleosaurus megacephalus (Stutchbury, 1846). It is proposed as the neotype of the species, as the holotype was destroyed in an air-raid on Bristol in November 1940. Details of the skull allow emendation of the diagnosis of the genus Rhomaleosaurus. Comparison of R. megacephalus with the Upper Liassic species, Rhomaleosaurus zetlandicus, shows that the former has a more gracile snout and a shallower lower jaw symphysis, and lacks squamosal-quadrate foramina. There may also be differences in the number and nature of the palatal grooves associated with presumed underwater olfaction. Lack of iron pyrites in the matrix surrounding the specimen allowed computed axial tomography (CAT)-scan sections to be obtained, which in association with the little-distorted nature of the skull, permitted a confident reconstruction of the skull. It shows a complete ring of circumorbital bones, and a suborbital fenestra. The braincase can be reconstructed from sagittal break-sections allied with CAT-scan sections. A stapes is identified. A poorly preserved dentition comprises conical, striated, teeth with caniniforms on each premaxilla and at the front of each maxilla. Although very similar to the later species, this skull is not so well adapted for apprehending and dismembering large prey, as is R. zetlandicus.

An investigation into the neck of two plesiosauroid plesiosaurs: Cryptoclidus eurymerus and Muraenosaurus leedsii Unpublished MSc dissertation Cretaceous and Cenozoic sedimentary basins and geological evolution of the Canterbury region, South Island

Jan 1959
527

M Evans
B D Field
G H Browne

EVANS, M. 1993. An investigation into the neck of two plesiosauroid plesiosaurs: Cryptoclidus eurymerus and Muraenosaurus leedsii. Unpublished MSc dissertation, University College London, 63 pp. FIELD, B. D. and BROWNE, G. H. 1989. Cretaceous and Cenozoic sedimentary basins and geological evolution of the Canterbury region, South Island, New Zealand. New Zealand Geological Survey, Basin Studies, 2, 1±94. FLEMING, C. A. (ed.) 1959. Oceania. Fascicule 4. New Zealand. (Lexique Stratigraphique International, 6). Centre National de la Recherche Scienti®que, for Stratigraphic Commission of International Geological Congress, Paris, 527 pp.

Description de quelques espe Áces de reptiles de la Californie, pre Âce Âde Âe de l'analyse d'un syste Áme ge Âneral d'erpe Âtologie The English Upper Jurassic Plesiosauroidea (Reptilia) and a review of the phylogeny and classi®cation of the Plesiosauria

Jan 1981

Ðð Godefroit
P Sciau

ÐÐ GODEFROIT, P. and SCIAU, J. 1999 A new elasmosaurid plesiosaur from the Lower Jurassic of southern France. Palaeontology, 42, 927±952. BENTON, M. J. (ed.) 1993. The fossil record 2. Chapman and Hall, London, 845 pp. BLAINVILLE, H. D. de 1835. Description de quelques espe Áces de reptiles de la Californie, pre Âce Âde Âe de l'analyse d'un syste Áme ge Âneral d'erpe Âtologie et d'amphibiologie. Nouvelles Annales du Muse Âum d'Histoire Naturelle, Paris, Se Ârie 3, 4, 233±296. BROWN, D. S. 1981. The English Upper Jurassic Plesiosauroidea (Reptilia) and a review of the phylogeny and classi®cation of the Plesiosauria. Bulletin of the British Museum (Natural History), Geology Series, 35, 253±347. ÐÐ 1994. A taxonomic revision of the families Elasmosauridae and Cryptoclididae (Reptilia: Plesiosauroidea).

Localities referred to are shown on Text-®g. 1A. Plesiosauroidea: Elasmosauridae Mauisaurus haasti Hector, 1874. Lectotype: pelvis, paddle; Haumurian Stage (Maastrichtian) of Jed River near Gore Bay (North Canterbury, South Island) Includes Plesiosaurus australis of Hector 1874

Jan 1971

Synonymies
Gregg

Synonymies follow Welles and Gregg (1971). Localities referred to are shown on Text-®g. 1A. Plesiosauroidea: Elasmosauridae Mauisaurus haasti Hector, 1874. Lectotype: pelvis, paddle; Haumurian Stage (Maastrichtian) of Jed River near Gore Bay (North Canterbury, South Island). Includes Plesiosaurus australis of Hector 1874 (in part), Mauisaurus brachiolatus Hector, 1874, and Cimoliosaurus caudalis Hutton, 1894. Also includes Mangahouanga Stream (Hawkes Bay, North Island) specimens discussed by Wiffen and Moisley (1986).

Holotype: skull and apparently associated vertebrae; Piripauan or Haumurian Stage (Maastrichtian) of Manga-houanga Stream (Hawkes Bay, North Island) Referred material includes many elements of a juvenile, also from Mangahouanga Stream

Jan 1986

Tuarangisaurus Wiffen
Moisley

Tuarangisaurus keyesi Wiffen and Moisley, 1986. Holotype: skull and apparently associated vertebrae; Piripauan or Haumurian Stage (Maastrichtian) of Manga-houanga Stream (Hawkes Bay, North Island). Referred material includes many elements of a juvenile, also from Mangahouanga Stream, discussed by Wiffen and Moisley (1986).

The skull of the Callovian plesiosaur Cryptoclidus eurymerus, and the sauropterygian cheek Lithostratigraphy of Late Cretaceous to Early Pleistocene rocks of northern Canterbury

Jan 1941

±16 Ðð
±953 Ðð Milner
A C Taylor

Revue de Pale Âobiologie, Volume Spe Âcial (for 1993), 7, 9±16. ÐÐ and CRUICKSHANK, A. R. I. 1995. The skull of the Callovian plesiosaur Cryptoclidus eurymerus, and the sauropterygian cheek. Palaeontology, 37, 941±953. ÐÐ MILNER, A. C. and TAYLOR, M. A. 1986. New material of the plesiosaur Kimmerosaurus langhami Brown from the Kimmeridge Clay of Dorset. Bulletin of the British Museum (Natural History), Geology Series, 40, 225±234. BROWNE, G. H. and FIELD, B. D. 1985. Lithostratigraphy of Late Cretaceous to Early Pleistocene rocks of northern Canterbury, New Zealand. New Zealand Geological Survey, Record, 6, 1±63. CABRERA, A. 1941. Un plesiosauria nuevo del Cretaceo del Chubut. Revista Museo de La Plata (Section Paleontologõ Âa),

The geology of New Zealand

Jan 1978

R P Suggate
G R Stevens
Te Punga

SUGGATE, R. P., STEVENS, G. R. and TE PUNGA, M. T. (eds) 1978. The geology of New Zealand. Two volumes. Government Printer, Wellington, 820 pp.

The North Otago plesiosaur Newsletter of the Geological Society of New Zealand, 61, 47±48. ÐÐ 1983b. A summary of recent discoveries of pre-Quaternary vertebrates in southern New Zealand

Jan 1983

FORDYCE, R. E. 1983a. The North Otago plesiosaur. Newsletter of the Geological Society of New Zealand, 61, 47±48. ÐÐ 1983b. A summary of recent discoveries of pre-Quaternary vertebrates in southern New Zealand. Geological Society of New Zealand, Miscellaneous Publications, 30A, unpaginated abstract.

The geology of the Lower Shag Valley

Jan 1941
71-103

PATERSON, O. D. 1941. The geology of the Lower Shag Valley. Transactions and Proceedings of the Royal Society of New Zealand, 71, 32±58.

Description de quelques espe Áces de reptiles de la Californie, pre Âce Âde Âe de l'analyse d'un syste Áme ge Âneral d'erpe Âtologie et d'amphibiologie. Nouvelles Annales du Muse Âum d

Jan 1835

H D De

BLAINVILLE, H. D. de 1835. Description de quelques espe Áces de reptiles de la Californie, pre Âce Âde Âe de l'analyse d'un syste Áme ge Âneral d'erpe Âtologie et d'amphibiologie. Nouvelles Annales du Muse Âum d'Histoire Naturelle, Paris, Se Ârie 3, 4, 233±296.

Cretaceous and Cenozoic sedimentary basins and geological evolution of the Canterbury region, South Island

Jan 1989
1-94

FIELD, B. D. and BROWNE, G. H. 1989. Cretaceous and Cenozoic sedimentary basins and geological evolution of the Canterbury region, South Island, New Zealand. New Zealand Geological Survey, Basin Studies, 2, 1±94.

Paleogeographic reconstructions of New Zealand. Geological Society of New Zealand

Jan 1998
97-142

KING, P. R. 1998. Paleogeographic reconstructions of New Zealand. Geological Society of New Zealand, Miscellaneous Publication (Geology and Genes Symposium), 97, 45±48.

Sam Welles in New Zealand

Jan 1997
95-97

D R Gregg

GREGG, D. R. 1997. Sam Welles in New Zealand. Newsletter of the Geological Society of New Zealand, 114, 95±97.

Centre National de la Recherche Scienti®que, for Stratigraphic Commission of International Geological Congress

C A Fleming

FLEMING, C. A. (ed.) 1959. Oceania. Fascicule 4. New Zealand. (Lexique Stratigraphique International, 6). Centre National de la Recherche Scienti®que, for Stratigraphic Commission of International Geological Congress, Paris, 527 pp.

On a new plesiosaur from the Waipara River

Jan 1894
354-358

F W Hutton

HUTTON, F. W. 1894. On a new plesiosaur from the Waipara River. Transactions of the New Zealand Institute, 26, 354± 358.

Geology of the provinces of Canterbury and Westland, New Zealand. A report comprising the results of of®cial explorations

Jan 1879

J Von

HAAST, J. von 1879. Geology of the provinces of Canterbury and Westland, New Zealand. A report comprising the results of of®cial explorations. Times Of®ce, Christchurch, 486 pp.

Joan Wiffen and the Mangahouanga Stream reptiles: a pro®le

Jan 1984
29-32

I W Keyes

KEYES, I. W. 1984. Joan Wiffen and the Mangahouanga Stream reptiles: a pro®le. Newsletter of the Geological Society of New Zealand, 63, 29±32.

The development of paleoseaways around Antarctica

Jan 1992
7-30

L A Lawver
L M Gahagan
M F Coffin

LAWVER, L. A., GAHAGAN, L. M. and COFFIN, M. F. 1992. The development of paleoseaways around Antarctica. American Geophysical Union, Antarctic Research Series, 56, 7±30.

A New Marine Reptile (Sauropterygia) from New Zealand: Further Evidence for A Late Cretaceous Austral Radiation of Cryptoclidid Plesiosaurs

Abstract

No full-text available

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