Jorge Velez-Juarbe

• PhD
• Associate Curator at Natural History Museum of Los Angeles County

The absence of terrestrial apex predators on oceanic islands led to the evolution of endemic secondary apex predators like birds, snakes and crocodiles, and loss of defence mechanisms among species. These patterns are well documented in modern and Quaternary terrestrial communities of the West Indies, suggesting that biodiversity there assembled si...

Aetiocetids are a relatively diverse group of small toothed mysticetes that lived from the late Eocene through the late Oligocene in the North Pacific Ocean. They are characterized by a combination of morphological features that places them between earlier mysticetes (e.g., mammalodontids) and chaeomysticetes. Since the first aetiocetid was describ...

Evidence of trophic interactions are not scarce in the fossil record, yet these are mostly represented by fragmentary fossils exhibiting marks of ambiguous significance. Differentiating between marks of active predation and scavenging events is therefore often challenging. Here, we report on a dugongine sea cow skeleton (partial skull and vertebrae...

Synopsis Land-to-sea evolutionary transitions are great transformations where terrestrial amniote clades returned to aquatic environments. These secondarily aquatic amniote clades include charismatic marine mammal and marine reptile groups, as well as countless semi-aquatic forms that modified their terrestrial locomotor anatomy to varying degrees...

With their past and current diversities, West Indian caviomorph rodents dominate the terrestrial mammalian fauna of the Caribbean archipelago. Many of these species have recently become extinct, including the emblematic giant forms known as Heptaxodontidae. The higher-level systematics and content of this family have been widely disputed over the l...

Odontocetes first appeared in the fossil record by the early Oligocene, and their early evolutionary history can provide clues as to how some of their unique adaptations, such as echolocation, evolved. Here, three new specimens from the early to late Oligocene Pysht Formation are described further increasing our understanding of the richness and di...

Fossil cetaceans are often found in Miocene marine outcrops across the globe. However, because this record is not homogeneous, the dissimilar increase in occurrences, along with the sampling bias has created regions with extensive records and others with great scarcity. Among these, the Caribbean has remained enigmatic due to the lack of well-prese...

Records of aquatic mammal fossils (e.g. cetaceans, pinnipeds, sirenians, mustelids, and desmostylians) from Latin America (Mexico to Tierra del Fuego, including Antartica) span since the mid-1800s. Aquatic mammal fossils received little attention from the scientific community, with most of the first studies conducted by Northern Hemisphere research...

Analysis of the incisor enamel microstructure of extinct and extant West Indian caviomorph rodents emphasizes a clear microstructural distinction between the Echimyidae (Capromyinae and Heteropsomyinae) among Octodontoidea and the “Heptaxodontidae”, whose phylogenetic affinities are debated. All capromyines and heteropsomyines have a pattern of ena...

Extant istiophorids are open ocean apex predators that are extensively studied due to their ecological importance and high values for fisheries. Nevertheless, little is known about their evolution because of a fragmentary fossil record and extremely difficult taxonomy of fossil species. Here, we present a new phylogenetic hypothesis covering fossil...

The present 3D Dataset contains the 3D models analyzed in Benites-Palomino A., Velez-Juarbe J., Altamirano-Sierra A., Collareta A., Carrillo-Briceño J., and Urbina M. 2022. Sperm whales (Physeteroidea) from the Pisco Formation, Peru, and their Trophic role as fat-sources for Late Miocene sharks.

Shark–cetacean trophic interactions, preserved as bite marks in the fossil record, mostly correspond to isolated or fragmentary findings that bear limited information about major trophic patterns or roles. Here, we provide evidence of focalized foraging by sharks in the form of tooth bite marks over physeteroids fossil bones from the late Miocene o...

This study provides new stratigraphic data and identifications for fossil marine mammals from the Monterey Formation in the Capistrano syncline, Orange County, California, showing that there are two distinct marine mammal assemblages. Until now, marine mammals from the Monterey Formation of Orange County have been considered to represent a single a...

Body sizes of marine amniotes span six orders of magnitude, yet the factors that governed the evolution of this diversity are largely unknown. High primary production of modern oceans is considered a prerequisite for the emergence of cetacean giants, but that condition cannot explain gigantism in Triassic ichthyosaurs. We describe the new giant ich...

Sloths were among the most diverse groups of land vertebrates that inhabited the Greater Antilles until their extinction in the middle-late Holocene following the arrival of humans to the islands. Although the fossil record of the group is well known from Quaternary deposits in Cuba, Hispaniola, and Puerto Rico, remains from older units are scarce,...

The West Indies are a natural laboratory for the study of biogeography and evolution, especially for mammals. The modality of their arrival in the Caribbean islands is a highly controversial issue, and palaeontological evidence remains particularly elusive. Lower Oligocene deposits of Puerto Rico (c. 29.5 Ma) have recently yielded the oldest archip...

Potamosiren magdalenensis Reinhart, is an extinct species of manatee (Sirenia, Trichechidae, Trichechinae), which has only been recorded for the middle Miocene Honda Group, in the La Venta area (Huila Department, Colombia). A new specimen referable to Potamosiren cf. P. magdalenensis is reported herein, collected from the early Miocene Barzalosa Fo...

Facial compartmentalization in the skull of extant pygmy whales (Kogiidae) is a unique feature among cetaceans that allows for the housing of a wide array of organs responsible for echolocation. Recent fossil findings indicate a remarkable disparity of the facial bone organization in Miocene kogiids, but the significance of such a rearrangement for...

Twelve new specimens of fossil walruses are described from four Miocene units in California. The new material represents five taxa: (1) a specimen from the Santa Margarita Formation referred to Imagotaria downsi; (2) a specimen from the Valmonte Diatomite Member of the Monterey Formation referred to cf. Pontolis magnus; (3) six specimens from the M...

Biogeographical distributional patterns of cetaceans reflect dispersal events and colonization of the oceans from their ancestral area in the ancient Sea of Tethys~53 Ma. Likewise, they reveal several vicariance events throughout the evolutionary history of this group. However, our understanding of how these processes took place and what biogeograp...

This contribution contains the 3D models of the fossil teeth of two chinchilloid caviomorph rodents (Borikenomys praecursor and Chinchilloidea gen. et sp. indet.) discovered from lower Oligocene deposits of Puerto Rico, San Sebastian Formation (locality LACM Loc. 8060). These fossils were described and figured in the following publication: Marivaux...

The modern pygmy and dwarf sperm whales (Physeteroidea, Kogiidae) are remnants of a highly diverse group, which flourished in the Miocene oceans. Unlike their modern suction-feeding, deep-diving relatives, the past diversity of this family includes animals with disparate ecological habits. Here, we describe Scaphokogia totajpe, sp. nov., a new spec...

The nearly 200 species of direct-developing frogs in the genus Eleutherodactylus (the Caribbean landfrogs, which include the coquís) comprise an important lineage for understanding the evolution and historical biogeography of the Caribbean. Time-calibrated molecular phylogenies provide indirect evidence for the processes that shaped the modern anur...

By their past and present diversity, rodents are among the richest components of Caribbean land mammals. Their phylogenetic affinities, the timing of their arrival in the West Indies, and their biogeographical history are all ongoing debated issues. Here we report the discovery of rodent teeth from lower Oligocene deposits (~29.5 Ma) of Puerto Rico...

Crinoids are uncommon fossils in the Cenozoic. This scarcity means that even disarticulated elements are of note. Two species of the isocrinine Isselicrinus Rovereto are described from their disarticulated columns. Isselicrinus sp. A is from the upper Eocene Moritzian Stage of Tierra del Fuego. These crinoids have a robust column, varying from pent...

True seals (crown Phocidae) originated during the late Oligocene-early Miocene (approx. 27-20 Ma) in the North Atlantic/Mediterranean region, with later (middle Miocene, approx. 16-11 Ma) dispersal events to the South Atlantic and South Pacific. Contrasting with other pinnipeds, the fossil record of phocids from the North Pacific region is scarce a...

Herein, we describe a new early Miocene dugongine from marine deposits of the Culebra Cut (Gaillard Cut) of the Panama Canal. The new taxon, Culebratherium alemani, gen. et sp. nov., represents one of the few records of late Aquitanian–early Burdigalian sirenians and the oldest sirenian from Central America. A phylogenetic analysis places Culebrath...

Congreso Latinoam. Paleontol. Vertebr. ISSN: 2619-2616 (en linea) www.viclpv.com. Se describe un fragmento de maxilar izquierdo con los alvéolos de dP5–M1 y los M2–3 casi completos, posiblemente referible a Potamosiren cf. P. magdalenensis (Mammalia, Sirenia). El ejemplar (IGMp 450086) proviene de los niveles de lodolitas de la Formación Barzal...

We describe Titanotaria orangensis (gen. et. sp. nov.), a new species of walrus (odobenid) from the upper Miocene Oso Member of the Capistrano Formation of Orange County, California. This species is important because: (1) It is one of the best-known and latest-surviving tuskless walruses; (2) It raises the number of reported odobenid taxa from the...

Here, we describe the odobenid Nanodobenus arandai gen. et sp. nov., based on a nearly complete left mandible from the mid to late Miocene Tortugas Formation in Baja California Sur. Nanodobenus is distinguished among odobenids by displaying a unique combination of plesiomorphic and derived characters, such as narrow mandibular symphysis, well-devel...

Deposited over a short period of time during the Middle Miocene Climatic Optimum, the Sharktooth Hill Bonebed in California is one of the world’s densest marine vertebrate concentrations. Pinnipeds are represented here by odobenids and desmatophocids, but some are still poorly known. Herein, the mandibular morphology of the odobenid Neotherium miru...

Odontocetes first appear in the fossil record during the early Oligocene and soon after show a near-worldwide distribution. However, little is still known of their early diversity, especially in the North Pacific Region. A new taxon of stem odontocete with heterodont dentition, Olympicetus avitus, gen. et sp. nov., is described herein from the uppe...

A new taxon of stem otariid, Eotaria citrica sp. nov., is described from the upper Burdigalian to lower Langhian “Topanga” formation of Orange County, California. The new species is described from mandibular and dental remains that show a unique combination of plesiomorphic and derived characters. Specifically, it is characterized by having trencha...

Character/state matrix used for phylogenetic analysis.

Table S2. Loadings of PC1 and PC2.

Table S3. Distance between medoids of each cluster of species included in the principal component analysis.

Table S4. List of specimens used for body length estimates and their corresponding lengths based on equations from Churchill, Clementz & Kohno (2015).

Table S1. Measurements (in mm) and morphological features observed for sexual dimorphism and intraspecific variation.

We describe fossil kogiid periotics from the Lower Pliocene upper Bone Valley Formation in central Florida and the Lower to Upper Pliocene Yorktown Formation at Lee Creek Mine, North Carolina. The fossils show diagnostic characters that identify them as belonging to Kogiidae, such as three spines in the anterior process, presence of an incudal proc...

We provide a synopsis of ~60 million years of life history in Neotropical lowlands, based on a comprehensive survey of the Cenozoic deposits along the Quebra da Cachiyacu near Contamana in Peruvian Amazonia. The 34 fossil-bearing localities identified have yielded a diversity of fossil remains, including vertebrates, mollusks, arthropods, plant fos...

Aim Given its catastrophic consequences, the extinction of apex predators has long been of interest to modern ecology. Despite major declines, no present‐day species of marine apex predator has yet become extinct. Because of their vulnerability, understanding the mechanisms leading to their extinction in the past could provide insight into the natu...

In contrast to dominant mode of ecological transition in the evolution of marine mammals, different lineages of toothed whales (Odontoceti) have repeatedly invaded freshwater ecosystems during the Cenozoic era. The so-called 'river dolphins' are now recognized as independent lineages that converged on similar morphological specializations (e.g., lo...

Kogiids are known by two living species, the pygmy and dwarf sperm whale (Kogia breviceps and K. sima). Both are relatively rare, and as their names suggest, they are closely related to the sperm whale, all being characterized by the presence of a spermaceti organ. However, this organ is much reduced in kogiids and may have become functionally diff...

Here we describe a new taxon of late Oligocene dugongine from the Western Atlantic and Caribbean region. Known from cranial and postcranial material, Callistosiren boriquensis, gen. et sp. nov., differs from other members of the group by displaying the following unique combination of characters: nasal process of premaxilla tapering but thickened; s...

Editor: Ruth Stockey Premise of research. Humiriaceae occupy predominantly Neotropical lowland rainforests, with only a single Old World species in western Africa. Molecular divergence time estimates suggest that the family might have originated during the middle Cretaceous; however, fossil occurrences are lacking prior to the Paleocene. Here we pr...

We describe a new genus and species of early Oligocene halitheriine dugongid from the Western Atlantic region. Priscosiren atlantica, gen. et sp. nov., differs from all other halitheriine dugongids by displaying the following unique combination of characters: supraorbital processes dorsoventrally thin (≤1 cm) with well-developed prominent posterola...

Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass s...

We describe a new species of the halitheriine dugongid genus Metaxytherium from the late Oligocene of Florida and South Carolina. The new species is represented by cranial and postcranial material, including parts of the axial and appendicular skeleton. Metaxytherium albifontanum, sp. nov., differs from other species of Metaxytherium by the followi...

The Greater Antilles was once home to a diverse array of endemic groups of caviomorph rodents. Many of these became extinct, together with endemic insectivores, sloths, and primates, in what is widely considered an archtypical example of Quaternary extinction on oceanic islands. When and how the ancestors of these land mammals arrived on these isla...

Understanding the temporospatial distribution of paleoenvironments in the Panama Canal Basin is necessary to unravel the tectonic evolution of the Isthmus of Panama, especially in light of new evidence for early closure of the Central American Seaway. The La Boca Formation of the Gaillard Cut, Panama Canal, was originally defined as early Miocene m...

A partial postcranial skeleton (vertebrae and ribs) of an indeterminate sirenian is described from Selminum Tem cave in the Hindenburg Range, Western Province of Papua New Guinea. It was derived from a section of the Darai Limestone dating to the Burdigalian–Serravallian (early–middle Miocene) and representing shallow platform carbonates. The thora...

Seagrasses are a notable component of shallow marine habitats, especially in tropical and subtropical regions. Their fossil record extends back to the Mesozoic, but it is relatively poor and fragmentary, with large temporal and geographical gaps. As a result, very little is known about the paleobiogeography of these plants and how physical drivers,...

Fossil sirenians are well known from the Western Atlantic and Caribbean (WAC) region. Neogene records from the Atlantic coast of South America, although scarce, seem to reflect a similar taxonomic composition to its northern contemporaries. Fossil sirenians from Argentina are known from the late Miocene Parana and Ituzaingo formations in Entre Rios...

Here we describe Bohaskaia monodontoides, a new taxon of beluga-like odontocete cetacean from the early Pliocene Yorktown Formation of Virginia and North Carolina. Among odontocetes, Bohaskaia shares key characteristics of the rostrum and face with belugas (Delphinapterus leucas), narwhals (Monodon monoceros), and Denebola brachycephala from the la...

Extant sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past ∼26 million years, in different oceanic basins. Morphological differences among co-occurring sirenian taxa suggest that resource partitioning played a role in structuring...

Dorsal views of skulls of fossil dugongids from the Late Oligocene of Florida, showing the configuration of the premaxilla-frontal suture. Anterior to the right. (TIF)

Information on other potential sirenian multispecies assemblages; characters and matrix used in the phylogenetic analysis. (DOC)

Panama has produced an abundance of Neogene marine fossils both invertebrate (mollusks, corals, microfossils etc.) and vertebrate (fish, land mammals etc.), but marine mammals have not been previously reported. Here we describe a cetacean thoracic vertebra from the late Miocene Tobabe Formation, a partial cetacean rib from the late Miocene Gatun Fo...

Kutchisiren cylindrica, n. gen. n. sp., is a dugongine sirenian represented by a single skull with mandible from the Lower Miocene (Aquitanian or Burdigalian) Khari Nadi Formation in the district of Kutch (= Kachchh), Gujarat State, western India. It is characterized by a braincase of nearly cylindrical form, a strong rostral deflection of about 78...

Oligocene and Miocene fossil decapods from Puerto Rico and Cuba have been poorly known; new collections from these regions as well as from the Dominican Republic have now yielded several new reports. One new genus, Psygmophthalmus, and several new species (Neocallichirus aetodes, Neocallichirus? quisquellanus, Calappa pavimenta, Necronectes collins...

Aunque los dugones no viven actualmen-te en el Caribe, en el pasado esta parte del mundo poseía una diversidad de es p ec i es. QUIZÁS CUANDO LEAS el título de este artículo pensarás en ninfas marinas mitad humano y mitad pez de la mi-tología griega, o quizás en la pelirroja Ariel de la película de Disney. Pero los sirénidos no son criaturas mí-tic...

Carrie E. Schweitzer1, Jorge Velez-Juarbe2, Michael Martinez3, Angela Collmar Hull1, 4, Rodney M. Feldmann4, and Hernan Santos2

LOS CIENTÍFICOS que estudian dino-saurios al nivel del origen de sus des-cendientes emplumados-los pájaros-constantemente hacen afirmaciones de lo cercanos que son los dos gru-p o s. Términos como dinosaurios emplu-mados o dinosaurios avíanos ahora no causan tanta sorpresa co-mo hace 140 años, cuando uno de los defensores de Dar-win, Thomas Hu-xley...

QUIZÁS LO PRIMERO que se nos ocurre cuando pensamos en reptiles fósiles son los dinosaurios, plesiosaurios, ictiosau-rios o quizás pterodáctilos. De estos animales, aún no se han encontrado fó-siles en Puerto Rico-de hecho Cuba es la única isla del Caribe donde se han encontrado algunos de estos reptiles del Me s o z o i c o. Si buscáramos los rept...

El primer hallazgo de fósiles de can-grejos en Puerto Ri-co fue en 1966, cuando se encon-traron dos especies de cocolías o can-grejos portunidos en rocas del Mioceno (23.8-5.3 millones de años). cangrejos. Se estima que en un periodo de cuatro millones de años se originaron nueve especies de cangrejos terrestres en Jamaica del género Sesarma (gener...

The Indian gharial (Gavialis gangeticus) is not found in saltwater, but the geographical distribution of fossil relatives suggests a derivation from ancestors that lived in, or were at least able to withstand, saline conditions. Here, we describe a new Oligocene gharial, Aktiogavialis puertoricensis, from deltaic-coastal deposits of northern Puerto...

Fragmentary fossils from northwestern Puerto Rico document the existence of crocodyliforms during the Late Oligocene and Early Miocene. The remains are insufficient to establish new named species, but they are inconsistent with any other crocodylian known from the western hemisphere during the Cenozoic, including extant Alligator and Crocodylus. Th...

UN AMIGO se refería al descubrimiento de un gavial en Puerto Rico (noticia pu-blicada recientemente en este periódico) como un interesante hallazgo arqueoló-gico. Dado que continuará una serie de seis artículos de éste tipo, pensamos que valdría la pena comenzar con el tema de la paleontología y cómo esta ciencia di-fiere de la arqueología. La pale...

The first occurrence of crocodylians from the Quaternary of mainland Puerto Rico is re- ported from a cave in northern Puerto Rico: this rec- ord expands the distribution of crocodylians east- ward in the Caribbean region during this period. The occurrence of crocodylians in the Quaternary of Puerto Rico adds another taxon to the current list of ex...

Quarry 9 is among the richest microvertebrate localities in the Morrison Formation, having thus far produced the remains of dozens of Late Jurassic taxa. Because this lenticular claystone deposit records such a high diversity of contemporaneous species, it provides an exceptionally detailed view of their paleoecology and local paleoenvironment. In...