[Ichthyology • 2024] Sphyrna alleni • A New Hammerhead Shark (Carcharhiniformes: Sphyrnidae) from the Caribbean and the Southwest Atlantic

Sphyrna alleni 

Gonzalez, Postaire, Driggers, Caballero & Chapman, 2024

 

 DOI: 10.11646/zootaxa.5512.4.2

 

Abstract

Hammerhead sharks (Family Sphyrnidae) comprise a monophyletic Miocene radiation of carcharhiniform sharks characterized by their laterally expanded and dorsoventrally compressed head (‘cephalofoil’). The bonnethead shark (Sphyrna tiburo) is currently described as a single amphi-American hammerhead species composed of the subspecies Sphyrna tiburo tiburo in the Western Atlantic Ocean (WA) and S. tiburo vespertina in the Eastern Pacific Ocean (EP). Variation in mitochondrial DNA and cephalofoil shape suggest a species complex, with S. tiburo occurring in the U.S., Mexico, and Bahamas; S. aff. tiburo occurring from Belize to Brazil; and S. vespertina occurring in the EP. Morphometric, meristic, and genetic variation was used to resolve the bonnethead shark complex in the Western Atlantic. Twenty-three specimens (12 S. aff. tiburo from Belize and 11 S. tiburo from U.S.) were subject to sixty-one morphometric measurements and three meristic characters (counts of the number of precaudal vertebrae, lower and upper rows of functional teeth). An allometric formula was used to standardize any effect caused by differences in size of the individuals and data were analyzed with univariate and multivariate statistics. Sphyrna aff. tiburo and S. tiburo have non-overlapping vertebral counts (80-83 and 71-74 respectively) but no morphometric differences were detected. Although not captured in morphometric analysis, the cephalofoil of S. aff. tiburo has a more pointed anterior margin than S. tiburo that together with lobule shaped posterior margins gives the cephalofoil a distinctive shovel-shaped appearance. Concatenated mitochondrial sequences and 12 nuclear microsatellite markers clearly separated S. aff. tiburo and S. tiburo. We conclude that this complex comprises two species in the Western Atlantic, S. tiburo and S. alleni sp. nov., and we provide a description of the latter, which is distinguished by precaudal vertebral counts (80-83), a shovel-shaped cephalofoil with rounded posterior margins, and robust differences in mitochondrial and nuclear genetic markers. We suggest nuclear genetic and meristic examination of EP bonnetheads is needed to update the taxonomical status and redescribe S. vespertina.

Pisces, Shovelbill shark, morphology, mtDNA, nDNA, phylogenetics, species complex, taxonomy

Sphyrna alleni sp. nov.,

Cindy Gonzalez, Bautisse Postaire, William Driggers, Susana Caballero and Demian Chapman. 2024. 2024. Sphyrna alleni sp. nov., A New Hammerhead Shark (Carcharhiniformes, Sphyrnidae) from the Caribbean and the Southwest Atlantic. Zootaxa. 5512(4); 491-511. DOI: doi.org/10.11646/zootaxa.5512.4.2

[Ichthyology • 2023] Apristurus ovicorrugatus • What came first, the Shark or the Egg? Discovery of A New Species of Deepwater Shark (Carcharhiniformes: Scyliorhinidae) by investigation of Egg Case Morphology

Apristurus ovicorrugatus

 White, O'Neill, Devloo-Delva, Nakaya & Iglésias, 2023

DOI: 10.1111/jfb.15415

Abstract

Apristurus ovicorrugatus, a new species of deepwater catshark, is described from northwestern Australia. Unique egg cases belonging to an unknown species of Apristurus prompted a more detailed investigation of Apristurus specimens off northwestern Australia. One specimen previously identified as A. sinensis collected off Dampier Archipelago was found gravid with a single egg case. Removal of this egg case confirmed that this species was responsible for producing the unique egg cases previously recorded. The egg cases of this species have strong T-shaped longitudinal ridges on the dorsal and ventral surfaces which are unique in the genus Apristurus. The ridges most closely resemble those present in Bythaelurus canescens from South America, but are larger and always T-shaped. The holotype is closest morphologically to A. sinensis but differs in having a medium brown buccal cavity (vs. jet black), ridged egg cases (vs. smooth egg cases), fewer intestinal spiral valve turns and larger pectoral fins. The holotype is also similar, and closest on a molecular level, to A. nakayai with which it shares a unique synapomorphic character, the white shiny iris (apomorphic within the genus). A late-term embryo removed from an egg case superficially resembled the holotype except in having two parallel rows of enlarged dermal denticles on the dorsolateral predorsal surface. Recent nomenclatural changes to the genera Apristurus and Pentanchus are discussed and challenged. This study highlights the important contribution that egg case morphology has on oviparous elasmobranch taxonomy.

Keywords: Apristurus brunneus group, discovery, egg cases, genetics, new species, Pentanchidae

Lateral view of Apristurus ovicorrugatus n. sp. holotype (CSIRO H 3161-01, adult female 467 mm LT):
(a) fresh; (b) preserved

Dorsal view of trawled egg cases of Apristurus ovicorrugatus n. sp. (CSIRO H 8056-01); top egg case contained a 68.7 mm late-term embryo.

Scale bar = 10 mm

Egg case of Apristurus ovicorrugatus n. sp. (CSIRO H 9058-01) attached to octocoral (Thouarella sp.)

 Apristurus ovicorrugatus n. sp.

Synonymy: Apristurus sp.?: Human, 2011: 199, Figures 1, 6 (northwestern Australia); 

Apristurus sinensis (in part): Last & Stevens, 2009: 195 (northwestern Australia in part).

Vernacular: Ridged-egg Catshark.

Diagnosis: A small Apristurus species with the following combination of characters: eyes with shiny white iris (when fresh); head moderately long and relatively narrow, head length 23.8% LT, interorbital space 6.4% LT; snout moderately elongate, preoral length 10.0% LT, preorbital length 10.9% LT; mouth wide, its width 9.5% LT; pelvic–anal space 5.9% LT; anal fin large, base length 15.2% LT, posterior margin 11.5% LT; prepectoral length relatively long, about 21.1% LT; labial furrows long, not confined to mouth corners, uppers longer than lowers (3.8 vs. 2.4% LT); no enlarged denticles on upper or lower caudal fin; duodenum of intestine moderately sized, 15 intestinal spiral valves; 35 monospondylous centra; 33 precaudal-diplospondylous vertebrae; precaudal centra 68; females mature by 467 mm LT; egg case small (50.4–60.6 mm long), with 5–7 strong T-shaped ridges on dorsal and ventral surfaces.

 Etymology: Name derived from a combination of the Latin ovi (egg; genitive singular of ovum) and corrugatus (corrugated) in allusion to the corrugated egg cases that this species exhibits which are unique for the genus Apristurus. The name ovicorrugatus is treated as an adjective.

 

William T. White, Helen L. O'Neill, Floriaan Devloo-Delva, Kazuhiro Nakaya and Samuel P. Iglésias. 2023. What came first, the Shark or the Egg? Discovery of A New Species of Deepwater Shark by investigation of Egg Case Morphology. Journal of Fish Biology. DOI: 10.1111/jfb.15415

phys.org/news/2023-05-species-shark-unique-egg-cases.html 

[Ichthyology • 2022] Galeus friedrichi • A New Sawtail Catshark (Carcharhiniformes: Pentanchidae) from the Philippines

Galeus friedrichi  

 Ebert & Jang, 2022

 zenodo.org/record/7320085 

 Researchgate.net/publication/365411545

A new species of sawtail catshark, Galeus friedrichi n. sp., is described from the Philippines. The new species is separable from other western Pacific Galeus species by the absence of saddle or blotch markings, a large size, >50 cm TL, 40 monospondylous vertebrae, and 83 precaudal vertebrae. All regional Galeus, other than Galeus sauteri, can be distinguished by having a marking pattern made up of a series of dark to light saddle or blotch patterns beneath the dorsal fins and on the caudal fin. Galeus sauteri can be separated from G. friedrichi n. sp. by its relatively small adult size, <50 cm TL, and fewer precaudal vertebrae (73–76 vs. 83). The two other large regional species, G. longirostris and G. nipponensis are presently known only from Japan and Taiwan. The new species is the third Galeus species, after G. sauteri and G. schultzi, documented from the Philippines.

Key words: taxonomy, ichthyology, Chondrichthyes, elasmobranch, western Pacific Ocean. 

Galeus friedrichi n. sp.
holotype, CAS-ICH 247314, adult male, 534 mm TL, lateral view, after preservation.
paratype, CAS-ICH 247315, juvenile male, 455 mm TL , lateral view, after preservation.

Galeus friedrichi n. sp. holotype, CAS-ICH 247314, adult male, 534 mm TL, ventral view of head.

Galeus friedrichi, n. sp. 

Philippines Sawtail Catshark

Diagnosis. A large slender Galeus species distinguished from all regional congeners by a combination of an absence of saddle or blotch patterns on body and caudal fin (except G. sauteri); large size, exceeding 50 cm TL (except G. longirostris and G. nipponensis); a higher count of monospondylous vertebrae (40) (except G. longirostris and G. nipponensis); and 83 precaudal vertebrae.

Distribution. Known only from the type specimens caught off off Sikayab-Bukana, Dapitan City, Zamboanga del Norte, Philippines at a depth of 550 m.

Etymology. The new species is named in honor of Jürgen Friedrich, a European philanthropist and co-founder of the JAF Foundation (Switzerland), in recognition of his commitment to marine conservation, research, and advocacy.

David A. Ebert and Jessica J. Jang. 2022. Galeus friedrichi (Carcharhiniformes: Pentanchidae), A New Sawtail Catshark from the Philippines. Journal of the Ocean Science Foundation. 39, 45–53. 

DOI: 10.5281/zenodo.7320085 https://zenodo.org/record/7320085 

 Researchgate.net/publication/365411545_Galeus_friedrichi_a_new_sawtail_catshark_from_the_Philippines

[Ichthyology • 2022] Scyliorhinus hachijoensis • A New Species of Catshark (Carcharhiniformes: Scyliorhinidae) from the Izu Islands, Japan

 Scyliorhinus hachijoensis 

 Ito, Fujii, Nohara & Tanaka, 2022

DOI: 10.11646/zootaxa.5092.3.5

Abstract

A new species of catshark genus Scyliorhinus, S. hachijoensis sp. nov., is described for the islands of Mikurajima, Hachijojima, and Torishima in southeastern Japan. Scyliorhinus hachijoensis has clasper hooks, which is a common feature in males of the most closely related species (S. torazame), but is distinguished by its coloration (presence of dark spots), the height of its anal fin (higher than the caudal peduncle), and the shape of pectoral and pelvic fins, and dermal denticles. Molecular data also corroborates the new species as a distinct and monophyletic taxon by nucleotide sequence analysis of three mitochondrial DNA regions.

Key words: Scyliorhinus torazame, Scyliorhinus hachijoensis sp. nov., Chondrichthyes, morphology

 Scyliorhinus hachijoensis, external morphology.
(A, B) NSMT-P 135960, male, 370 mm TL (off the east coast of Hachijojima Island).
(C, D) NSMT-P 135961, female, 322 mm TL (off the east coast of Hachijojima Island). Panels show
(A, C) dorsal and (B, D) lateral views of the specimens.

Scale bar = 30 mm.

Close-ups of the head of  Scyliorhinus hachijoensis, NSMT-P 135960, male, 370 mm TL (off the east coast of Hachijojima Island).
Panels show (A) lateral, (B) dorsal, and (C) ventral views.

 Scale bar = 20 mm.

Scyliorhinus hachijoensis sp. nov.

New English name: Cinder cloudy catshark; 

New Japanese name: Fukami-torazame.

Diagnosis: A species of Scyliorhinus distinguished by its anterior nasal flaps not reaching the upper lip (vs. flaps reaching upper lip, and sometimes covering it, in S. canicula, S. cervigoni, S. comoroensis, S. duhamelii, S. garmani and S. stellaris); nasoral grooves absent and posterior nasal flaps situated posterior to excurrent apertures (vs. nasoral grooves prexents and posterior nasal flaps laterally situated in S. canicula and S. duhamelii); mouth length less than half of mouth width (vs. mouth length more than or equal half of mouth width except in S. torazame and S. ugoi); anal fin height more than caudal peduncle height (vs. less than caudal peduncle height in S.boa, S. duhamelii, S. torazame and S. torrei), and greater than or equal to half of mouth width (vs. less than half of mouth width in S. boa, S. capensis, S. duhamelii, S. haeckelii, S. hesperius, S.meadi, S. torazame, S. torrei and S. ugoi); saddles darker than the background color (vs. inconspicuous or absent in S. boa, S. cabofriensis, S. cervigoni, S. duhamelii, S. garmani and S. torrei, and dark lines in S. retifer); body grayish brown to dark brown with well-defined light spots and small dark spots (vs. spots absent in S. retifer, yellow to golden spots in S. capensis, light spots absent in S. cervigoni, S. garmani, S. meadi and S. retifer, and dark spots absent in S. capensis, S. comoroensis, S. hesperius, S. meadi, S. torazame and S. torrei); light spots spiracle-sized or larger (vs. predominantly smaller than spiracles in S. boa, S. cabofriensis, S. canicula, S. duhamelii, S. stellaris and S. ugoi); dark spots smaller than spiracles (vs. predominantly larger than spiracles in S. cervigoni, S. duhamelii, S. garmani, S. haeckelii and S. stellaris); number of monospondylous vertebrae 34–36 (vs. counts higher except in S. duhamelii, S. torazame and S. torrei); clasper with hooks (vs. absent in all other species except S. torazame); accessory terminal cartilage present (vs. absent in S. cabofriensis, S. cervigoni, S. comoroensis, S. duhamelii, S. haeckelii, S. stellaris, S. torrei and S. ugoi); egg case surface with irregularities (vs. smooth in all other species).

Distribution: This species was recorded from the waters around the Izu Islands, Japan (Fig. 7). All specimens were captured by longline fishing for Splendid alfonsino, at depths of ca. 100–200 m around Mikurajima Island, ca. 200–400 m around Hachijojima Island, and ca. 500–600 m around Torishima Island.

Etymology: The species name “hachijoensis” refers to the species’ main collection area, Hachijojima Island. The English name is derived from “Cinderella”, because the dark spots on the body surface are similar to black ashes “cinder”. The Japanese name “Fukami” means “deep sea”.

Egg cases of (A, B)  Scyliorhinus hachijoensis and (C, D) S. torazame.
 (A, C) Dorsal view, scale bar = 10 mm. (B, D) Close-up of surface.

 Scale bar = 2 mm.

Nanami Ito, Miho Fujii, Kenji Nohara and Sho Tanaka. 2022. Scyliorhinus hachijoensis, A New Species of Catshark from the Izu Islands, Japan (Carcharhiniformes: Scyliorhinidae). Zootaxa. 5092(3); 331-349. DOI: 10.11646/zootaxa.5092.3.5

[PaleoIchthyology • 2021] Rare Evidence of Shark-on-shark Trophic Interactions in the Fossil Record

One possible way in which the shark centra (CMM-V-2700) could have been bitten. This illustration depicts an active predatory encounter between two requiem sharks (aff. Carcharhinus sp.).

in Perez, Godfrey & Chapman, 2021. 

DOI: 10.4202/app.00911.2021

Original drawing by Tim Scheirer (formerly CMM). 

Coloration added by Clarence Schumaker (CMM).

Direct evidence of chondrichthyan trophic interactions in the fossil record is largely limited to bite traces on prey items but may also be found within the gut contents of exceptionally well-preserved individuals or as inclusions within coprolites. Shark bite traces are typically observed on durable, bony skeletal elements. Previous publications have shown shark bite traces on skeletal elements of fossil fishes, marine mammals, marine reptiles, and even a pterosaur, offering direct evidence of active predation, failed predation, and/or scavenging. Herein, we describe the first evidence of shark bite traces preserved on cartilaginous vertebral centra of other sharks. Four carcharhiniform centra have been identified from the Neogene Atlantic Coastal Plain, bearing chondrichthyan bite traces, of which two have partial teeth still embedded within them. In one specimen, CMM-V-2700, CT scans showed remodeling of the tissue around two partial teeth embedded in the centrum, indicating that the bitten individual survived the encounter. While shark-on-shark predation is common among living taxa, capturing evidence of these interactions in the fossil record is exceptionally rare.

Key words: Chondrichthyes, Carcharhinidae, trophic interaction, shark predation, shark-on-shark, bite traces, trace fossils, Neogene.

Centrum of Carcharhinidae indet. (CMM-V-2700) from the Miocene Calvert Formation in Chesapeake Beach, MD, USA.
 Centrum in articular cross-sectional (A), lateral (B), and articular (C) views; CT-scan in articular view (D); CT-scan in lateral view (E). Arrows indicate the two shark teeth embedded in and protruding from the upper quadrant of the centrum.

Scale bars 10 mm.

One possible way in which the shark centra (CMM-V-2700) could have been bitten. This illustration depicts an active predatory encounter between two requiem sharks (aff. Carcharhinus sp.).

Original drawing by Tim Scheirer (formerly CMM). 

Coloration added by Clarence Schumaker (CMM).

Victor J. Perez, Stephen J. Godfrey, and Phillip F. Chapman. 2021. Rare Evidence of Shark-on-shark Trophic Interactions in the Fossil Record. Acta Palaeontologica Polonica. 66(4); 847-856. DOI: 10.4202/app.00911.2021

 livescience.com/rare-shark-fossils-reveal-ancient-attacks

[PaleoIchthyology • 2021] Feeding Ecology has shaped the Evolution of Modern Sharks

in Bazzi, Campione, ... et Ahlberg, 2021. 

DOI: 10.1016/j.cub.2021.09.028 

 facebook.com/VitorSilvaPaleoArtista 

Highlights: 

• Shark tooth morphologies track changing habitats and resource availability

• Tooth shape correlates with diet in extant shark species

• Declines in lamniform disparity can be linked with dietary “specialization”

• Modern lamniforms are more disparate than coeval carcharhiniforms

Summary

Sharks are iconic predators in today’s oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary “specialization,” their recent disparity rivals that of “generalist” carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.

 

Keywords: Lamniformes, Carcharhiniformes, geometric morphometrics, dental disparity, feeding ecology, environmental change, ecomorphology

Lamniformes and Carcharhiniformes across the last 83 million years.

Illustration: José Vitor Silva

 facebook.com/VitorSilvaPaleoArtista 

 Mohamad Bazzi, Nicolás E. Campione, Benjamin P. Kear, Catalina Pimiento and Per E. Ahlberg. 2021. Feeding Ecology has shaped the Evolution of Modern Sharks. Current Biology. In Press. DOI: 10.1016/j.cub.2021.09.028

In brief: Bazzi et al. analyze the evolution of lamniform and carcharhiniform shark over the last 83 Ma. These closely related clades are shown to have undergone marked morphological segregation, with a combination of habitat change, prey availability, and feeding strategies influencing their community composition, diversity, and ecology over time.

phys.org/news/2021-10-favourite-food-million-year-chronicle.html

  facebook.com/VitorSilvaPaleoArtista/photos/2075065865976555

[Ichthyology • 2021] Mustelus andamanensis • Revision of the Genus Mustelus (Carcharhiniformes: Triakidae) in the northern Indian Ocean, with Description of A New Species and A Discussion on the Validity of M. walkeri and M. ravidus

Mustelus andamanensis 

  White, Arunrugstichai & Naylorn 2021

 

Andaman Smoothhound || DOI: 10.1007/s12526-021-01161-4

 twitter.com/WillWhiteSharks 

Abstract

The species of Mustelus Linck, 1790 occurring in the northern Indian Ocean are revised and a new species, Mustelus andamanensis sp. nov., is formally described. Previously considered to be conspecific with M. mosis Hemprich & Ehrenberg, 1899, the new species is currently only known from the Andaman Sea. The Red Sea and Arabian Sea populations of Mustelus mosis differ in vertebral counts and degree of coverage of buccopharyngeal denticles in the mouth, but these characters alone are not considered strong enough evidence to separate into two species. Mustelus andamanensis sp. nov. is genetically (based on NADH2 sequences) closest to M. mosis but differs in having a subdivided palatoquadrate (vs. palatoquadrate not divided). The new species is morphologically closest to M. widodoi White & Last, 2006, but differs in several morphological characters and on a molecular level. Mustelus stevensi White & Last, 2008 is confirmed from the northern Indian Ocean for the first time based on a single specimen taken off southeastern Myanmar. Mustelus walkeri White & Last, 2008 is found to be a junior synonym of M. antarcticus Günther, 1870. The use of buccopharyngeal patterns and vertebral counts in isolation from other morphological differences and molecular data in this genus is also discussed.

Keywords: Smoothhound sharks, Myanmar, Thailand, NADH2 sequences, Synonymy

Family Triakidae Gray, 1851

Genus Mustelus Linck, 1790

Mustelus mosis Hemprich & Ehrenberg, 1899

Arabian Smoothhound

Mustelus stevensi White & Last, 2008

Western Spotted Smoothhound

Lateral view of the fresh holotype of Mustelus andamanensis sp. nov., CSIRO H 8426-01 (female 427 mm TL), from Thailand. Scale bar = 50 mm

Mustelus andamanensis sp. nov. 

Andaman Smoothhound

Etymology: Specific name in allusion to the water body this species is currently known from, the Andaman Sea.

 Distribution: Known only from the Andaman Sea, with confirmed records from off Ranong Province of Thailand (Arunrugstichai et al. 2018). 

William T. White, Sirachai Arunrugstichai and Gavin J.P. Naylor. 2021. Revision of the Genus Mustelus (Carcharhiniformes: Triakidae) in the northern Indian Ocean, with Description of A New Species and A Discussion on the Validity of M. walkeri and M. ravidus. Marine Biodiversity. 51: 42. DOI: 10.1007/s12526-021-01161-4

 twitter.com/WillWhiteSharks/status/1379999752209633284

[Ichthyology • 2019] Akheilos suwartanai • A New Genus and Species of Catshark (Carcharhiniformes: Scyliorhinidae) from eastern Indonesia

 Akheilos suwartanai  

White, Fahmi & Weigmann, 2019 

Ambon Catshark  || DOI: 10.11646/zootaxa.4691.5.2

  twitter.com/WillWhitesharks 

Abstract

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 claspers, broad subocular ridges under eyes, posterior nasal flaps present, tips of rostral cartilage fused into a rostral node. It represents the first record of this subfamily outside of the Americas. Akheilos differs from the other genus in the subfamily, Schroederichthys in a combination of: clasper groove not fused dorsally, ventral lobe of caudal fin produced, more intestinal valve turns, anal fin slightly larger than second dorsal fin, and in colour pattern.

Keywords: Pisces, Schroederichthys, Schroederichthyinae, new genus, new species, catshark, Indonesia

Figure 1. Akheilos suwartanai n. sp., holotype, MZB 18227, adult male, 537 mm TL, in (A) lateral, (B) dorsal and (C) ventral views.

Family Scyliorhinidae Gill, 1862 

Subfamily Schroedericthyinae Compagno, 1988 

Genus Akheilos n. gen. White, Fahmi & Weigmann

Etymology. Name comes from the Greek mythological sea daemon Akheilos who was a handsome boy transformed into a shark by the goddess Aphrodite as punishment for his boasting that he was more beautiful than her.

Akheilos suwartanai White, Fahmi & Weigmann, n. sp. 

Ambon Catshark

Etymology. Named after the first director of the Research and Development Center of Oceanology, Indonesian Institute of Sciences (LIPI) in Ambon, Atjep Suwartana.

William T. White, Fahmi Fahmi and Simon Weigmann. 2019. A New Genus and Species of Catshark (Carcharhiniformes: Scyliorhinidae) from eastern Indonesia. Zootaxa. 4691(5); 444–460. DOI: 10.11646/zootaxa.4691.5.2  

twitter.com/WillWhitesharks/status/1191166718892101632

[Ichthyology • 2019] Parmaturus angelae • A New Species of Parmaturus (Carcharhiniformes: Scyliorhinidae) from Brazil, Southwestern Atlantic

Parmaturus angelae

 Soares, Carvalho, Schwingel & Gadig, 2019

 DOI: 10.1643/CI-18-152  

twitter.com/ASIHCopeia

Abstract
A new Southwestern Atlantic species of Parmaturus, P. angelae, new species, is described from two specimens captured off Brazil. It is distinguished from congeners by the following characters: origin of the first dorsal fin anterior to pelvic-fin origin, presence of well-developed upper and lower caudal crests of denticles, dorsal fins subequal, lateral denticles teardrop-shaped and lacking lateral cusplets, denticles evenly spaced, proportional dimensions, and vertebral counts. Parmaturus angelae, new species, is the second species of the genus reported from the Atlantic Ocean and only the third species outside of the Indo-West Pacific region. Parmaturus remains rather poorly defined as only two species have been studied anatomically in any detail.

Fig. 2. Parmaturus angelae, new species, holotype, MZUSP 124000, female, 398 mm TL. Dorsal and lateral view. 

Parmaturus angelae, new species

Proposed common names: Brazilian Filetail Catshark,

 Ângela’s Catshark (Portuguese)

 Etymology.— The specific name angelae is dedicated to the last author’s granddaughter, Angela

Karla Diamantina De Araújo Soares, Marcelo Rodrigues De Carvalho, Paulo Ricardo Schwingel and Otto Bismarck Fazzano Gadig. 2019. A New Species of Parmaturus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae) from Brazil, Southwestern Atlantic.  Copeia. 107(2); 314-322. DOI: 10.1643/CI-18-152 

  twitter.com/ASIHCopeia/status/1134481991645237249

[Ichthyology • 2019] Carcharhinus obsolerus • Lost before Found: A New Species of Whaler Shark (Carcharhiniformes: Carcharhinidae) from the Western Central Pacific known only from Historic Records

Carcharhinus obsolerus

White, Kyne & Harris, 2019

Lost Shark  || DOI: 10.1371/journal.pone.0209387  

Painting by Lindsay Marshall (www.stickfigurefish.com.au) 

twitter.com/WillWhitesharks

Abstract

Carcharhinus obsolerus is described based on three specimens from Borneo, Thailand and Vietnam in the Western Central Pacific. It belongs to the porosus subgroup which is characterised by having the second dorsal-fin insertion opposite the anal-fin midbase. It most closely resembles C. borneensis but differs in tooth morphology and counts and a number of morphological characters, including lack of enlarged hyomandibular pores which are diagnostic of C. borneensis. The historic range of C. obsolerus sp. nov. is under intense fishing pressure and this species has not been recorded anywhere in over 80 years. There is an urgent need to assess its extinction risk status for the IUCN Red List of Threatened Species. With so few known records, there is a possibility that Carcharhinus obsolerus sp. nov. has been lost from the marine environment before any understanding could be gained of its full historic distribution, biology, ecosystem role, and importance in local fisheries.

Fig 1. Lateral view of Carcharhinus obsolerus sp. nov. (NMW 61463; female holotype 433 mm TL).
A. Preserved specimen; B. Painting by Lindsay Marshall (www.stickfigurefish.com.au). 

Fig 2. Head of Carcharhinus obsolerus sp. nov. (NMW 61463; Holotype). 433 mm TL female:
A. lateral view; B. ventral view.

Fig 5. In situ teeth of Carcharhinus obsolerus sp. nov. (ANSP 77121, paratype). 370 mm TL female:
A. upper teeth; B. lower teeth.

Carcharhinus obsolerus White, Kyne & Harris sp. nov.  

Synonymy: Carcharhinus sp.: [Compagno, 1979]: 517, 520, 523, 536 (Borneo); [Compagno, 1988]: 319, 321, 327 (Vietnam, Borneo, and Thailand); [Compagno et al., 1998]: 1359, fig (Vietnam, Borneo, and Thailand)

Carcharhinus porosus: [Compagno et al., 2005]: 71 (Borneo, Saigon, and Bangkok)

Carcharhinus undescribed small species: [Compagno, 1984]: 497 (Borneo, Vietnam, and Thailand)

Carcharhinus sp. (= ‘Carcharhinus porosus’): [Compagno et al., 1998]: 1322.

Carcharhinus sp. A: [Compagno et al., 2005]: 307, fig, pl. 62 (Borneo, Vietnam, and Thailand); [Voigt et al., 2011]: 103, fig 50

Holotype: NMW 61463, female 433 mm TL, Bangkok, Thailand, no date or collector recorded.

Paratypes: ANSP 76859, female late-term embryo 339 mm TL, Ho Chi Minh City, Vietnam, Dec. 1934, coll. H. Rutherfurd; ANSP 77121 (paratype of Carcharhinus tephrodes Fowler), female 370 mm TL, Baram, Sarawak, Malaysian Borneo, 1897, coll. A.C. Harrison Jr. & H.M. Hiller.

Diagnosis.: A small species of Carcharhinus with: a slender body and tail; no interdorsal ridge; head parabolic in dorsal view, relatively wide, interorbital space 11.2–12.0% TL; eyes relatively large, length 2.4–2.9% TL, 10.0–15.1 times in head length; no row of enlarged hyomandibular pores alongside each mouth corner; upper anterior teeth broadly triangular and serrated, with large and coarse (non-lobate) serrations basally; lower anterior teeth with narrower, mostly straight cusps; cusps of upper and lower anterolateral teeth with apical margin slightly recurved; no lateral cusplets; total tooth row counts 27–31/26–29; posterior edge of the mandibular plate with an elongate and crescentic indentation; second dorsal-fin origin well posterior of anal-fin origin, about opposite anal-fin midbase, second dorsal-fin origin to anal-fin origin 1.3–2.5% TL, 0.3–0.6 times second dorsal-fin base; first dorsal fin triangular, not falcate, origin about opposite first third of pectoral-fin inner margin length, free rear tip just anterior to pelvic-fin origins, length 1.7–1.9 times height, inner margin 1.9–2.5 in base; second dorsal fin much smaller than first, slightly smaller than anal fin; base 1.4–2.0 times height; height 22–31% of first dorsal-fin height; anal fin height 1.2–1.5 times second dorsal height, base 1.1–1.2 times second dorsal-fin base; total vertebral counts 114–120, monospondylous precaudal counts 36–40, diplospondylous precaudal counts 18–19, diplospondylous caudal counts 56–66, precaudal counts 54–58; no distinct black markings on fins.

....

Distribution: Uncertain; collection records indicate southern South China Sea (Gulf of Thailand, Vietnam, Malaysian Borneo).

The distribution of Carcharhinus obsolerus is uncertain. Given that this species has not been seen in many decades, a better understanding of the distribution of this species is unlikely unless archaeological or paleontological records are found. While Baram in Sarawak is likely an accurate collection locality, both Bangkok and Ho Chi Minh City specimens may have been caught in other South-east Asian locations and brought into these cities where bigger markets exist. Thus, there is a possibility it had a much more restricted distribution than the three known specimens allude to, but it cannot be ruled out that it had a wider distribution in the South-east Asian region.

Etymology: The specific name is Latin for ‘extinct’ (obsolerus) in allusion to the fact that the species has not been recorded in many decades. Proposed English vernacular name: Lost Shark.

William T. White, Peter M. Kyne and Mark Harris. 2019. Lost before Found: A New Species of Whaler Shark Carcharhinus obsolerus from the Western Central Pacific known only from Historic Records. PLoS ONE. 14(1): e0209387. DOI: 10.1371/journal.pone.0209387  

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[Ichthyology • 2018] Bythaelurus stewarti • A New Microendemic Species of the Deep-water Catshark Genus Bythaelurus (Carcharhiniformes, Pentanchidae) from the northwestern Indian Ocean, with Investigations of Its Feeding Ecology, Generic Review and Identification Key

Bythaelurus stewarti  

Weigmann, Kaschner & Thiel, 2018

DOI:  10.1371/journal.pone.0207887 

Abstract

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 distinguished from its morphologically and geographically closest congener, B. hispidus (Alcock), by the larger size (maximum size 44 vs. 39 cm TL, maturity size of males 35–39 vs. 21–28 cm TL), darker fresh coloration and dark grayish-brown mottling of the ventral head (vs. ventral head typically uniformly yellowish or whitish). Furthermore, it has a strongly different morphology of dermal denticles, in particular smaller and less elongate branchial, trunk and lateral caudal denticles that are set much less densely and have a surface that is very strongly and fully structured by reticulations (vs. structured by reticulations only in basal fourth). In addition, the new species differs from B. hispidus in having more slender claspers that are gradually narrowing to the bluntly pointed tip without knob-like apex (vs. claspers broader and with distinct knob-like apex), more spiral valve turns (11–12 vs. 8–10) and numerous statistical differences in morphometrics. A review of and a key to the species of Bythaelurus are given.

Fig 1. Bythaelurus stewarti n. sp., holotype, ZMH 26251, adult male, 425 mm TL, in (A) lateral, (B) dorsal, and (C) ventral views. Scale bar: 5 cm.

 Fig 2. Bythaelurus stewarti n. sp., (A) paratype, ZMH 26253, gravid female, 425 mm TL, (B) paratype, ZMH 26252, juvenile male, 340 mm TL, and (C) paratype, ZMH 26253, female embryo, 137.3 mm TL in lateral views. Scale bars: 5 cm.

Bythaelurus stewarti Weigmann, Kaschner & Thiel n. sp.

Error Seamount Catshark

Diagnosis: A medium-sized Bythaelurus species with the following characteristics: body firm and slender; snout long (preorbital length 4.9–7.4% TL) and broad, bell-shaped in dorsoventral view with distinct lateral indention; pre-outer nostril length 0.6–1.4 times internarial space; preorbital snout length 0.7–1.1 times interorbital space; preoral snout length 0.8–1.7 times in mouth width; eye length 10.2–15.5 times in predorsal distance, 4.9–7.7 times in head length and 1.2–2.3 times eye height; head length 2.2–2.6 times width at level of maximum outer extent of anterior nostrils; head width at level of maximum outer extent of anterior nostrils 1.1–1.3 times width at level of lateral indention of head, 1.2–1.6 times preorbital length, and 8.1–10.1% TL; tongue and roof of mouth densely set with knob-like oral papillae; pelvic-fin anterior margin 1.6–3.5 times in pectoral-fin anterior margin; first dorsal-fin base 1.3–2.3 times in interdorsal space; length of second dorsal-fin inner margin 0.8–2.3 times in second dorsal-fin height; second dorsal-fin base length 5.1–8.9% TL; anal-fin base 0.7–1.9 times interdorsal space. Coloration: dorsally dark grayish-brown with rather indistinct dark blotches at nape, on flank, below both dorsal fins, and across caudal fin; ventral side grayish-white, usually with dark grayish-brown mottling on head. Upper jaw with 64–85 and lower jaw with 64–88 rows of small tricuspidate teeth with outer surface of crown furrowed by strong longitudinal ridges and strongly structured by reticulations; monospondylous trunk vertebrae centra 37–42, diplospondylous precaudal centra 37–45, total centra 125–140. Branchial, trunk and lateral caudal-fin dermal denticles loosely set, their surface very strongly and fully structured by reticulations. Claspers rather long and very slender, gradually narrowing to bluntly pointed tip without knob-like apex, inner margin length 10.1–11.3% TL, base width 1.4–1.5% TL; clasper hooks present along inner edge of large exorhipidion, large envelope overlapping part of clasper groove, inner lobe with rhipidion, cover rhipidion, pseudopera and pseudosiphon. The reproductive mode is yolk-sac viviparous. Bythaelurus stewarti n. sp. differs from all congeners in the distribution, which is apparently restricted to the Error Seamount. It further differs from all congeners in a higher spiral valve turn count (11–12 vs. 6–10) and in the morphology of branchial, trunk and lateral caudal-fin dermal denticles, which are loosely-spaced and not overlapping even in adult specimens of the new species, whereas they are closely-set and overlapping in all other Bythaelurus species. Compared to its morphologically and geographically closest congener, the new species further differs in a larger size, a ventral head with dark mottling, claspers that gradually narrow to the bluntly pointed tip without knob-like apex, and a surface of dermal denticles that is very strongly and fully structured by reticulations.

Fig 18. Map of the Indian Ocean depicting the verified occurrences of nine species of Bythaelurus in the Indian Ocean.
The occurrences are based on examined material except for B. clevai (based on one examined specimen plus catch locations of the type specimens taken from Séret [12] and B. alcockii (no specimen available, catch location of the lost holotype indicated as Arabian Sea in Garman [40]). Bythaelurus alcockii: black pentagon, B. bachi: black stars, B. clevai: white triangles, B. hispidus: black (holotype) and white (other specimens) circles, B. lutarius: black triangles, B. naylori: white stars, B. stewarti n. sp.: black and white diamonds, B. tenuicephalus: white squares, B. vivaldii: black square. Inset of the Gulf of Aden area depicts the catch locations of the holotype (black diamond) and paratypes (black and white diamonds) of Bythaelurus stewarti n. sp. on Error Seamount and catch locations of 100 comparative specimens of B. hispidus from off the Socotra Islands (white circles). Country abbreviations follow ISO 3166–1 (OM = Oman, SO = Somalia, YE = Yemen).

Distribution: The new species is known only from the Error Seamount (Mount Error Guyot) in 380–420 m depth (see map in the Discussion section). It is apparently a microendemic species restricted to this isolated Seamount.

Etymology: The new species is named after the late filmmaker and shark conservationist Rob Stewart, who inspired the second author and stimulated her interest in sharks.

Simon Weigmann, Carina Julia Kaschner and Ralf Thiel. 2018. A New Microendemic Species of the Deep-water Catshark Genus Bythaelurus (Carcharhiniformes, Pentanchidae) from the northwestern Indian Ocean, with Investigations of Its Feeding Ecology, Generic Review and Identification Key.  PLoS ONE. 13(12): e0207887. DOI:  10.1371/journal.pone.0207887