
Matthias F W StehmannICHTHYS Ichthyol. Res. Lab. & Consultant · one man dept.
Matthias F W Stehmann
PhD
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Publications (171)
Simple Summary
Skates of the genus Leucoraja Malm, 1877, are small to medium-sized skates that usually have a short, obtusely angled snout. Until now, 14 valid species of this genus have been identified mostly in the Atlantic, but also in the Indian Ocean. In the 1970s and 1980s, a total of eight specimens of an unusual skate species were collected...
A new deep-sea softnose skate, Notoraja hesperindica, is described based on six specimens caught in 1230–1600 m depths off southern Mozambique and northwestern Madagascar in the western Indian Ocean. The new species is a medium-sized species of Notoraja Ishiyama, 1958 reaching a total length of at least 539 mm. It is the only Notoraja species known...
The dark-mouth skate, Raja arctowskii Dollo, 1904 from Antarctic waters is an extraordinary case in skate taxonomy. For more than 100 years, this species has been known only from three empty egg capsules and the species as such has remained undescribed due to the lack of specimens that could be assigned to Dollo’s small capsules. Since trawled egg...
A new deep-water catshark, Bythaelurus bachi, is described based on 44 specimens caught on the southern Madagascar Ridge in the southwestern Indian Ocean. The new species is the only stout-bodied Bythaelurus with oral papillae in the region and is distinguished from all congeners by the plain beige to light gray-brown coloration, high diversity in...
The first illustrated guide to the over 630 known species of rays found on the planet. Rays are among the largest fishes and evolved from shark-like ancestors nearly 200 million years ago. Rays of the World is the first complete pictorial atlas of the world's ray fauna and includes information on many species only recently discovered by scientists...
Sinobatis kotlyari n. sp. is described, based on the nearly adult 331 mm TL holotype male from 1400 m depth in the southeastern Indian Ocean at Broken Ridge. The new species is assigned to Sinobatis due to mainly characters of its clasper and cranium fontanelle distinguishing it from congeners and other anacanthobatid skates with clasper features k...
The third and fourth records of the rare oceanic dalatiid shark Euprotomicroides zantedeschia Hulley
& Penrith, 1966 from off Chile, near Juan Fernandez Islands, are described. A nearly mature male of 455 mm
total length (TL) was caught by a Russian trawler in 1985, and a presumably mature female of 515 mm TL by a
Dutch stern trawler in 2008. Both...
A new deep-water legskate, Sinobatis brevicauda, is described based on two specimens caught on the remote Saya de Malha Bank in the central western Indian Ocean. The new species is easily distinguished from all other described anacanthobatids by the short tail. It is the only Sinobatis species described from the western Indian Ocean and differs fro...
Highly localized concentrations of elasmobranch egg capsules of the deep-water skate Bathyraja richardsoni were discovered during the first remotely operated vehicle (ROV) survey of the Hebrides Terrace Seamount in the Rockall Trough, north-east Atlantic Ocean. Conductivity-temperature-depth profiling indicated that the eggs were bathed in a specif...
A new species of the Indo-Pacific skate genus Okamejei is described based on 10 specimens caught around the Socotra Islands (northwestern Indian Ocean). The type series of Okamejei ornata n. sp. was sampled during cruise 17 of RV ‘Vityaz’ along the deep western Indian Ocean in 1988/89. The new species represents the fifth species of Okamejei in the...
A new species of the widely in temperate and tropical latitudes distributed skate genus Rajella is described based on an almost adult male specimen from the western Indian Ocean off South Mozambique. The holotype of R. paucispinosa n. sp. was caught during cruise 17 of RV ‘Vityaz’ along the deep western Indian Ocean in 1988/89. It is the northernmo...
The first mature male of Bathyraja schroederi (Krefft, 1968) is reported based on a single specimen caught by longline in nearly 2000 m depth at 53°S, 57°W in the Western South Atlantic. This is only the third record after the original description of this very rare deepwater skate that is mainly found in the southwestern Atlantic and with records o...
The African dwarf sawshark Pristiophorus nancyae is one of the least known species of the genus. The species was described in 2011 based on type specimens in rather poor condition and with a very restricted distribution off southern Mozambique. Since nine further specimens in mostly excellent condition became available, the authors reinvestigated t...
Anacanthobatis ori is one of the least known species of the family Anacanthobatidae with only four juvenile specimens reported. The species remained assigned to the genus Anacanthobatis sensu lato due to the lack of an adult male as external and skeletal clasper characters are the essential diagnostic features for the differentiation of genera and...
A new genus and species of the carcharhiniform family Pseudotriakidae is described based on three specimens caught near the Socotra Islands in the northwestern Indian Ocean. The first specimen and holotype of Planonasus parini g. n. and sp. n. was caught during cruise 17 of RV 'Vityaz' in 1988/89 along the deep western Indian Ocean. Two further spe...
The generic status of many skate species has been revised during the past six decades by various authors having introduced new diagnostic morphological and anatomical characters. As a consequence, the original family Rajidae and its very diverse type genus Raja Linnaeus, 1758 have been split into several families, subfamilies, genera and subgenera...
Neoraja iberica n. sp. is described from the Portuguese and Spanish sector of the Iberian Peninsula south coast slope, based on a series of 50 type specimens representing all sizes of both sexes. This pygmy skate species was found with a maximum total length of 316 mm for females and 327 mm for males. The smallest specimens were a 55 mm neonate fem...
Five variously developed embryos [142–279 mm total length (LT)] from egg capsules from the Porcupine Seabight, north-eastern Atlantic (1541 m depth) are used to establish the ontogeny and early life history of Bathyraja richardsoni. The capsules of this species and two half-formed ones from the shell glands of a large (1620 mm LT) female Bathyraja...
Describing a new deepwater Bathyraja skate from western Indian Ocean.
A new deep-water catshark, Apristurus melanoasper n. sp., is described based on 53 specimens from the
North Atlantic Ocean at 512 to 1520 m depth. This new species is characterized by having longer upper labial furrow than the lower one, high count of spiral intestine valves, a long abdomen, large dermal denticles and black coloration of the body....
A new species of electric ray of the genus Torpedo is described from the eastern Gulf of Aden, northwestern Indian Ocean. Torpedo adenensis, n. sp., is placed in the subgenus Torpedo due to the presence of small, knoblike papillae around its spiracles. It is distinguished from all other congeners by its unique dorsal coloration, consisting of a uni...
Part B of this series, the Batomorphii is continued with the description and illustration of the tooth morphology (SEM-photographs) with additional information about the tooth vascularisation of the order Torpediniformes. Differential diagnosis and a classification of the torpediniform taxa from the odontological point of view are also presented. I...
A principal scale for identifying maturity stages of cartilaginous fishes is proposed for the first time. It applies to oviparous sharks, skates and holocephalans and mainly aplacental viviparous sharks and distinguishes a different number of maturity stages for females and males. The background information and observations were gathered predominan...
Five variously developed embryos [142-279 mm total length (L-T)] from egg capsules from the Porcupine Seabight, north-eastern Atlantic (1541 m depth) are used to establish the ontogeny and early life history of Bathyraja richardsoni. The capsules of this species and two half-formed ones from the shell glands of a large (1620 mm L-T) female Bathyraj...
Part C of this series describes and illustrates with SEM or macrophotos the morphology of the tooth plates, the spines of the first dorsal fin and frontal tenacula of extant holocephalan genera. A differential diagnosis and systematic conclusions are summarized in the results. Key words: Holocephali - Chimaeriformes - Chimaeroidei - Callorhynchidae...
Benthobatis kreffti n. sp. is d̀escribed as the third species of this genus of blind deep-water electric rays, based on 150 specimens taken from the continental slope off South Brazil. The new species is the smallest within the genus (TL less than 300 mm) and is compared with both congeners, B. marcida from the north-western Atlantic and B. moresby...
Part B of this series, the Batomorphii, is continued with the remaining taxa of the dasyatoid family Dasyatidae and the plesiobatoid family Plesiobatidae (additional material) and the supraspecific taxa of the Myliobatidae (including some doubtful taxa). The tooth morphology of their representatives, as specified in the title, is described and illu...
Resumen
Available published and unpublished information on the distribution , environment and biology of batoid fishes occurring off Brazil, Uruguay and Argentina is summarized and reviewed for sixty species. Zoogeographic provinces proposed by Lopez (1963, 1964) are considered an adequate framework to define the distribution of these species. The...
Described species: Aetoplatea tentaculata, Disceus thayeri, Plesiotrygon iwamae, Potamotrygon histrix, Taeniura lymma, Trygonoptera testacea, Urogymnus asperrimus, Urolophoides matsubarai, Urolophus cruciatus, Urotrygon mundus
Described species: Aetoplatea tentaculata, Amphotistius kuhlii, Dasyatis pastinaca, Gymnura altavela, Hexatrygon longirostris, Himantura uarnak, Pastinachus sephen, Pteroplatytrygon violacea, Taeniura grabata, Urogymnus asperrimus, Urolophoides matsubarai
A new deep-water catshark, Apristurus aphyodes n. sp., is described from 1014 to 1800 m depth in the Eastern North Atlantic Ocean. The description is based on a total of 30 type specimens, which include immature and mature males and females, ranging 209.2 to 540.0 mm in total length. This new species is distinguishable from the other 10 Atlantic co...
Described species: Anoxypristis cuspidata, Aptychotrema bougainvillei, Platyrhina sinensis, Platyrhinoides triseriata, Pristis pectinata, Rhina ancylostoma, Rhinobatos rhinobatos, Rhynchobatus djiddensis, Trygonorrhina fasciata, Zanobatus schoenleinii, Zapteryx brevirostris
Described genus: Anoxypristis, Pristis
Neoharriotta pumila is described from the northwestern Indian Ocean slope waters off Somalia and the Socotra Islands. The description is based on a total of 48 type specimens, 13 of which were selected for detailed morphological study. Both sexes are represented, ranging 97-258 mm body length (BDL) and 316-728 mm total length (TL), taken from 100-1...
Described species: Arhynchobatis asperrimus, Bathyraja richardsoni, Cruriraja parcomaculata, Irolita waitii, Notoraja tobitukai, Pavoraja (Insentiraja) laxipella, Pavoraja (Pavoraja) nitida, Pseudoraja fischeri, Raja (Atlantoraja) cyclophora, Raja (Okamejei) kenojei, Rhinoraja longicauda
Part B, Nos. 1a and 1b of this series, comprising of the Batomorphii the first and second sections on the Rajoidei, is continued with the last group of rajoid taxa as far as material was available. The tooth morphology of representatives of eleven more genera and subgenera, namely Arhynchobatis, Bathyraja richardsoni-type, Cruriraja, Irolita, Notor...
An immature male of B. papilionifera had already been trawled during the third fishery expedition to South America in 1971 seven years prior to the type series obtained at two stations of the fourth expedition in 1978. The additional record was taken somewhat north of the type locality on the continental slope off North Argentina. This fourth and s...
Described species: Bathyraja albomaculata, Bathyraja spinicauda, Psammobatis rudis, Raja lintea, Raja (Amblyraja) radiata, Raja (Dipturus) batis, Raja (Leucoraja) naevus, Raja (Raja) clavata, Raja (Rajella) bathyphila, Raja (Rajella) fyllae, Raja (Rioraja) agassizi, Raja (Rostroraja) alba, Sympterygia bonapartei
An early adolescent male of R. clavata was caught at 280-260 m depth on the slope of Walters Shoal on the southern Madagascar Ridge. It is probable that this specimen migrated along the ridge from south Madagascar, where sporadic occurrence of the species has been reported. -from Author
Described species: Anacanthobatis (Schroederobatis) americanus, Anacanthobatis (Springeria) longirostris, Breviraja spinosa, Dactylobatus armatus, Gurgesiella (Fenestraja) plutonia, Gurgesiella (Gurgesiella) dorsalifera, Malacoraja senta, Neoraja caerulea, Pavoraja asperula
Kurzfassung
Ergebnisse der Eorschungsreisen des CTS 'Wakber Herwig' nach Sudamerika. LXXII. Patagonotothen kreffti sp. п., eine neue patagonische Nototheniidenart von der Burdwood Bank im Siidwestadantik (Pisces, Perciformes, Nototheniidae).
Mit 13 Exemplaren aus Sammlungsbestanden des ZIN und ISH wird Patagonotothen kreffti sip. n. beschrieben, ei...