Simon Weigmann

Elasmo-Lab, Hamburg and Chair of the Integrative Taxonomy Working Group of the IUCN SSC Shark Specialist Group

The taxonomy of the enigmatic dark-mouth skate, Bathyraja arctowskii (Dollo, 1904), from the Southern Ocean was finally resolved after more than 100 years of ambiguity in 2021. This species is the smallest known species of the species-rich deep-water skate genus Bathyraja Ishiyama, 1958, which attains a total length of only about 61 cm and appears...

Sampling efforts on the Saya de Malha Bank (part of the Mascarene Plateau, western Indian Ocean) unveiled three unusual small juvenile angel shark specimens, that were a much paler color than the only known western Indian Ocean species, Squatina africana Regan, 1908. However, it took many years before further specimens, including adults of both sex...

Longnose skates have great economic importance in South American fisheries, and in order to preserve them it is important to have a well-defined taxonomic status of their species. Dipturus lamillai was recently described for Malvinas Islands waters based on morphological and molecular comparisons with Zearaja chilensis. Although D. lamillai has bee...

Etmopteridae (lantern sharks) is the most species-rich family of sharks, comprising more than 50 species. Many species are described from few individuals, and recollection of specimens is often hindered by the remoteness of their sampling sites. For taxonomic studies, comparative morphological analysis of type specimens housed in natural history co...

Morphological and molecular examinations of angelshark samples from the northwestern Indian Ocean, collected by a Thai fishing vessel in February 2017, offered an opportunity to explore the diversity of angelsharks in this region. All specimens were similar to Squatina africana Regan, 1908 on several characteristics, such as the presence of simple...

Recent sampling efforts and examinations of museum material provided evidence for a complex of species within Acroteriobatus leucospilus (Norman, 1926). The present manuscript contains a redescription of A. leucospilus involving the syntypes and additional material, as well as formal descriptions of two new species of Acroteriobatus Giltay, 1928. A...

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 s...

A new species of lanternshark, Etmopterus brosei sp. nov. (Squaliformes: Etmopteridae), is described from the southeastern Atlantic and southwestern Indian oceans. The new species resembles other members of the Etmopterus lucifer Jordan & Snyder, 1902 clade in having linear rows of dermal denticles, and most closely resembles the conspecific E. scu...

The species composition of batoid fishes from coastal waters of the Socotra Archipelago is reviewed, with confirmed records of the wedgefish Rhynchobatus djiddensis (Forsskål, 1775) and four new records of sharkrays, wedgefishes, and guitarfishes based on collected specimens, including one species from Abd al-Kuri Island, Rhina ancylostoma Bloch &...

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...

Recent sampling efforts in Madagascar and Zanzibar, as well as examinations of six-gilled sawsharks in several museum collections provided evidence for a complex of species within Pliotrema warreni Regan. The present manuscript contains a redescription of P. warreni involving the syntypes and additional material, as well as formal descriptions of t...

The Portuguese dogfish Centroscymnus coelolepis is a wide‐ranging deep‐water shark and a common by‐catch component of the catches of several mid to deep‐water fisheries. In the present study, two new records from the Southwestern Atlantic Ocean are reported based on specimens caught by bottom‐longline fishing vessels operating in the Argentinean‐Ur...

A new genus and species of catshark is described based on a single specimen collected off Ambon in the Maluku Islands of eastern Indonesia. Akheilos suwartanai belongs to the subfamily Schroederichthyinae which differs from the other catsharks in a combination of: similar sized dorsal fins, supraorbital crests present, pseudosiphon present on clasp...

A new species of the genus Planonasus is described from off southwestern India and Sri Lanka in the northern Indian Ocean. The new species occurs along the upper continental slope from 200 to 1000 m deep and was landed in fisheries for gulper sharks (Centrophorus spp.). Planonasus indicus sp. n. externally closely resembles P. parini (Carcharhinifo...

Using the last taxonomic review of chondrichthyans of the world, we selected the species distributed in the north‐western Atlantic Ocean (NWA) and compare it with the available published literature related to the class Chondrichthyes in the Venezuelan exclusive economic zone. We also revised information from worldwide databases such as: FAO (NWA‐31...

A new deep-water catshark, Bythaelurus stewarti, is described based on 121 examined specimens caught on the Error Seamount (Mount Error Guyot) in the northwestern Indian Ocean. The new species differs from all congeners in the restricted distribution, a higher spiral valve turn count and in the morphology of the dermal denticles. It is distinguishe...

The genus Okamejei Ishiyama, 1958 contains 12 valid species of rare deep-water skates with distributions in the Indian and Western Pacific Oceans. Two species, O. heemstrai (McEachran & Fechhelm, 1982) and O. ornata Weigmann, Stehmann & Thiel, 2015, occur exclusively in the Western Indian Ocean. The former species is originally described from off K...

A new very small deep-water catshark, Bythaelurus vivaldii, is described based on two female specimens caught off Somalia in the northwestern Indian Ocean during the German ‘Valdivia’ expedition in 1899. It is morphologically closest to the recently described B. bachi, which is the only other Bythaelurus species in the western Indian Ocean that sha...

Supplementary Table I of Weigmann, S. (2017), Reply to Borsa (2017): Comment on ‘Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity by Weigmann (2016)’. Journal of Fish Biology 90, 1176–1181. 10.1111/jfb.13234

Supplementary Table II (as of November 26, 2016) of Weigmann, S. (2017), Reply to Borsa (2017): Comment on ‘Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity by Weigmann (2016)’. Journal of Fish Biology 90, 1176–1181. 10.1111/jfb.13234

Im Zeitraum von Juli 2013 bis Februar 2016 wurden im Rahmen dieses Vorhabens historische und aktuelle Daten zum Vorkommen von Knorpelfischarten in Nord-und Ostsee zusammengetragen und ausgewertet. Der Schwerpunkt der Analysen lag dabei auf den in deutschen Meeresgebieten von Nord-und Ostsee nachgewiesenen Arten. Für diese Knorpelfischarten wurden E...

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...

In the course of the NSF-funded project “Jaws and Backbone: Chondrichthyan Phylogeny and a Spine for the Vertebrate Tree of Life”, morphological and molecular data were collected for a huge number of species (including type specimens). Molecular studies using mitochondrial and nuclear markers with dense taxon sampling corroborate that the skates co...

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...

Molecular analyses and information gleaned from an examination of the newly available adult male of the North-West Pacific skate, Okamejei jensenae Last & Lim, supported earlier concerns that the species might be mis-assigned. Morphological data based on this specimen supported its placement in a new genus Orbiraja that is assigned to the recently...

A new species of lanternshark, Etmopterus alphus (Squaliformes: Etmopteridae), is described from the south-western Indian Ocean. The new species resembles other members of the ‘Etmopterus lucifer’ clade in having linear rows of dermal denticles and most closely resembles E. molleri from the south-western Pacific. The new species is fairly common al...

The Roughskin Dogfish Centroscymnus owstonii is one of the most widespread deepwater shark species, but its global distribution is mostly based on patchy records. In this study, C. owstonii was reinvestigated with focus on its poorly known distribution in the western and eastern Indian Ocean. Previous records of the species from the Seychelles, whi...

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...

An annotated checklist of the chondrichthyan fishes (sharks, batoids and chimaeras) of the world is presented. As of 7 November 2015, the number of species totals 1188, comprising 16 orders, 61 families and 199 genera. The checklist includes nine orders, 34 families, 105 genera and 509 species of sharks; six orders, 24 families, 88 genera and 630 s...

A new dwarf deep-water catshark, Bythaelurus tenuicephalus, is described based on one adult and one juvenile male specimen from off Tanzania and Mozambique in the western Indian Ocean. The new species differs from its congeners by its slender head and snout, which is only slightly bell-shaped in dorsoventral view without distinct lateral indention....

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 deep-water catshark of the genus Apristurus Garman, 1913 is described based on nine specimens from the Gulf of Aden in the northwestern Indian Ocean. Apristurus breviventralis sp. nov. belongs to the ‘brunneus group’ of the genus and is characterized by having pectoral-fin tips reaching beyond the midpoint between the paired fin bases, a much...

A new deep-water catshark of the genus Apristurus Garman, 1913 is described based on nine specimens from the Gulf of Aden in the northwestern Indian Ocean. Apristurus breviventralis sp. nov. belongs to the ‘brunneus group’ of the genus and is characterized by having pectoral-fin tips reaching beyond the midpoint between the paired fin bases, a much...

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...

A new species of whaler shark, Carcharhinus humani sp. nov., is described based on five type specimens from the western Indian Ocean near the Socotra Islands, off Kuwait, Mozambique, and South Africa. The new species represents the fifth species of the C. dussumieri/sealei group and the third species of the C. sealei subgroup. The new species is th...

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...

Knowledge about distribution and habitat requirements of species is important for analyzing their role in marine ecosystems or establishing sanctuaries. However, knowledge is scarce especially in many chondrichthyan species. In this study, the spatial distribution of the stingray Neotrygon kuhlii on the Australian North and Northwest Shelf was pred...

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...

A collection of nine shark specimens from six different species, obtained in 1993 from the Gulf of Thailand, was examined in this study. The sharks were determined, morphometrically and meristically analyzed, photographically documented, and compared with relevant literature. Additionally, further available material from the fish collections of the...

A collection of 24 rays from eight different species, obtained in 1993 from the marine shelf around Thailand, was examined in this study. The rays were determined, morphometrically and meristically analyzed, photographically documented and compared with relevant literature and available further collection material. The tails of Dasyatis akajei were...

As part of the sampling efforts during the DIVA-II expedition several Tanaidacea of the genus Neotanais were captured in the Guinea and the Cape Basin in the tropical and southern East Atlantic Ocean. Two different species were sampled, Neotanais rotermundiae sp. n. from the Guinea and Neotanais guskei sp. n. from the Cape Basin. The distribution o...