[Ichthyology • 2021] Glaucostegus younholeei • A New Species of Giant Guitarfish (Rhinopristiformes: Glaucostegidae) from the northern Bay of Bengal, Bangladesh

Glaucostegus younholeei

Habib & Islam, 2021

DOI: 10.11646/zootaxa.4995.1.7

  twitter.com/HabibKaziAhsan

Abstract

A new species of giant guitarfish, Glaucostegus younholeei sp. nov., is described from 13 specimens, 730–933 mm total length, collected from fish landing center of Bangladesh Fisheries Development Corporation in Cox’s Bazar district of Bangladesh. The new species is distinguished from congeners in having the following combination of characters: Body brownish or greyish in color with a narrowly wedge-shaped disc, and long narrow bluntly pointed snout (angle 31–40°), and broad oblique nostrils with the narrow anterior opening. Nostrils about half of the mouth width, subequal (0.98–1.33) to internasal width; ~55–57 nasal lamellae; anterior nasal flaps slightly penetrating into internasal space, their interspace 2.20– 2.61 in length of the posterior nasal aperture. Orbit very small in adults, diameter 8.19–11.62 in preorbital length, 2.25–2.69 in interorbital space. Rostral ridges almost joined along their entire length; margin of cranium sharply demarcated before eyes. Spiracular folds very short and widely separated. Skin rough, densely covered with small denticles, more coarsely granular on the dorsal surface than ventrally, enlarged between orbits and in a distinct band between nape and first dorsal fin. Tail relatively longer, length 1.15–1.48 in disc length; dorsal fins narrowly spaced, interspace 1.32–2.11 in base length of the first dorsal fin. Clasper length in adult male 4.37–5.70 in total length. Phylogenetic analysis of DNA barcode sequences also shows the clear divergence of Glaucostegus younholeei from other congeneric species obtained from GenBank. A key is provided to the 8 known members including new species of the genus Glaucostegus.

Keywords: Pisces, Bangladeshi guitarfish, taxonomy, morphology, DNA Barcoding, Vulnerable

Glaucostegus younholeei sp. nov., 

 

Kazi Ahsan Habib and Md Jayedul Islam. 2021. Description of A New Species of Giant Guitarfish, Glaucostegus younholeei sp. nov. (Rhinopristiformes: Glaucostegidae) from the northern Bay of Bengal, Bangladesh. Zootaxa. 4995(1); 129-146. DOI: 10.11646/zootaxa.4995.1.7

Researchgate.net/publication/352817163_a_new_species_of_Glaucostegus_from_the_northern_Bay_of_Bengal_Bangladesh

  twitter.com/HabibKaziAhsan/status/1410482809349689345

[Ichthyology • 2021] Acroteriobatus andysabini & A. stehmanni • Resolution of the Acroteriobatus leucospilus Species Complex, with A Redescription of A. leucospilus (Norman, 1926) (Rhinopristiformes, Rhinobatidae) and Descriptions of Two New western Indian Ocean Species of Acroteriobatus

Acroteriobatus leucospilus (Norman, 1926)

in Weigmann, Ebert & Séret, 2021.

DOI: 10.1007/s12526-021-01208-6

 

Abstract

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. All specimens of both new species were found in the western Indian Ocean. Individuals of the first new species, hereafter referred to as Acroteriobatus andysabini sp. nov., were identified originating from Madagascar, and specimens of the second new species, hereafter referred to as Acroteriobatus stehmanni sp. nov., were only found off Socotra Islands at the junction between the Gulf of Aden and the Arabian Sea. Both new species appear to be endemic to the respective region and allopatric to A. leucospilus and occur in coastal waters to at least 80 m and 43 m depth, respectively. They differ from A. leucospilus in a number of characteristics including the maximum size and coloration in fresh. Acroteriobatus andysabini sp. nov. is a large species growing to more than 100 cm total length (TL) and with elongated bluish-gray spots on snout giving “stripe-nosed” appearance; numerous small bluish-gray spots on pectoral, pelvic, dorsal, and caudal fins; brown spots on trunk and fin bases; lateral tail folds striped orange and white; and ventral surface largely white but with a V-shape pattern of faint to dark speckled black spots on snout tip. Acroteriobatus stehmanni sp. nov. is a small species growing to ~62 cm TL and with sparse patterning with small bluish-gray circular spots confined to snout tip, posterior pectoral-fin margins, a pair on midbody, and few on posterior pelvic-fin margins, rather indistinct small to larger dark brown spots, and lateral tail folds and ventral surface white. Acroteriobatus leucospilus is a medium-sized species growing to ~96 cm TL and with patterning similar to A. andysabini sp. nov. but ventral surface uniformly white and lateral tail folds white or striped blue and brown. Taxonomical differences include nasal lamellae counts (42–48 in A. andysabini sp. nov. vs. 43–48 in A. stehmanni sp. nov. vs. 37–41 in A. leucospilus), snout angle (76–85° vs. 71–77° vs. 68–81°), and dorsal head length (24.2–33.5% vs. 17.2–22.8% TL vs. 24.0–29.2% TL). A key to the species of Acroteriobatus is given for the first time.

Keywords: Chondrichthyes, Elasmobranchii, Systematics, Guitarfishes, Taxonomy, Morphology

Family Rhinobatidae Bonaparte 1835

Genus Acroteriobatus Giltay, 1928

Type species: Rhinobatus (Syrrhina) annulatus Smith 

in Müller & Henle, 1841 

by subsequent designation

Acroteriobatus andysabini sp. nov.,
Fig. 1 SAIAB 97396, juvenile male holotype, 565 mm TL fresh, in total dorsal view taken directly after catching. Photograph by Elaine Heemstra, NRF-SAIAB
Fig. 2 SAIAB 97396, juvenile male holotype, 550 mm TL, in total dorsal view. Scale bar: 5 cm. Photograph courtesy Marsha Englebrecht. 
Fig. 3 SAIAB 97396, juvenile male holotype, 550 mm TL, in total ventral view. Scale bar: 5 cm. Photograph courtesy Marsha Englebrecht.

Acroteriobatus andysabini sp. nov. Weigmann, Ebert & Séret

Diagnosis: A large Acroteriobatus species distinguished by the following combination of characters: dorsal surface smooth, without prominent thorns or tubercles, except for enlarged granular denticles partially around orbital rims and irregularly distributed along midline from nape to somewhat anterior to first dorsal-fin origin; absent between dorsal fins and upper caudal fin. Snout semi-translucent with elongated bluish-gray spots giving “stripe-nosed” appearance, numerous small bluish-gray spots covering disc and pectoral, pelvic, dorsal, and caudal fins on a brown background with larger, slightly darker, indistinct brown spots covering the tail and fin bases; outer edges of pelvic-fin margins white, lateral tail folds striped orange and white; ventral surface white, except for a V-shape pattern of faint to dark speckled black spots on snout tip. Nasal lamellae 42–48; upper jaw tooth row count ~80–87; 179–185 post-synarcual centra; 195–200 total vertebral segments; 64–68 total pectoral skeleton radials.

Distribution: Acroteriobatus andysabini sp. nov. is presently only known from the coastal waters surrounding Madagascar and may be endemic to this region (Fig. 13). Records are from off Tôlanaro, Anosy region, and Cape Andavaka (southeastern Madagascar), Toliara and Ankilibe (southwestern Madagascar), and Antongil Bay (northeastern Madagascar). Its depth range is from shallow coastal waters to at least 80 m. Fricke et al. (2018) reported A. leucospilus as a new species record for Madagascar but commented that the species had been misidentified previously as Rhinobatos (= Acroteriobatus) annuulatus by several earlier authors.

Etymology: The species name andysabini is in honor of Andy Sabin for his gracious support of the Lost Sharks project at the Pacific Shark Research Center.

 Acroteriobatus stehmanni sp. nov.
Fig. 16 ZMH 25557, adult female paratype, 602 mm TL fresh, in total dorsal view taken directly after catching. Scale bar: 5 cm. The photograph was taken and kindly provided by Matthias Stehmann. 
Fig. 17 ZMH 25558, adult female paratype, 594 mm TL fresh, in total dorsal view taken directly after catching. Scale bar: 5 cm. The photograph was taken and kindly provided by Matthias Stehmann. 

Fig. 14 ZMH 25553, adult male holotype, 597 mm TL, in total dorsal view. Scale bar: 5 cm. 
Fig. 15 ZMH 25553, adult male holotype, 597 mm TL, in total ventral view. Scale bar: 5 cm

Acroteriobatus stehmanni sp. nov. Weigmann, Ebert & Séret

 

Diagnosis: A small Acroteriobatus species distinguished by the following combination of characters: dorsal surface smooth, without prominent thorns or tubercles, except for slightly enlarged granular denticles partially around orbital rims and rather regularly distributed along midline from nape to or to somewhat anterior to first dorsal-fin origin; absent between dorsal fins and upper caudal fin. Snout semi-translucent with a few, somewhat elongated bluish-gray spots only giving it a very reduced stripe-nosed appearance, patterning with small bluish-gray circular spots generally sparse and confined to symmetrical patterns on snout tip, posterior pectoral-fin margins, a pair of tiny spots on midbody behind occipital joint, and few spots on posterior pelvic-fin margins; indistinct brown spots on the body and dorsal and caudal fins; ventral surface white except for a blackish blotch and two tiny black spots on ventral snout tip in smallest juvenile paratype. Nasal lamellae 43–48; upper jaw tooth row count ~64–78; 181–186 post-synarcual centra; 194–200 total vertebral segments; 63–67 total pectoral skeleton radials.

Distribution: Acroteriobatus stehmanni sp. nov. is presently only known from the coastal waters surrounding the Socotra Islands and may be endemic to this region (Fig. 13). It is known from 36 to 43 m depth.

Etymology: The species is named in honor of Dr. Matthias F.W. Stehmann for his invaluable contributions to chondrichthyan taxonomy, particularly with respect to skates. He taught SW and BS chondrichthyan taxonomy, collected all type specimens of the new species, and kindly provided fresh photographs of two of them.

Acroteriobatus leucospilus, underwater photograph showing the vivid live coloration.

photograph by Dennis King.

Acroteriobatus leucospilus (Norman, 1926)

(Blue-spotted guitarfish)

 

Diagnosis: A medium-sized Acroteriobatus species distinguished by the following combination of characters: dorsal surface smooth, without prominent thorns or tubercles, except for slightly enlarged granular denticles partially around orbital rims and rather regularly distributed along midline from nape to near first dorsal-fin origin; absent between dorsal fins and upper caudal fin. Snout semi-translucent with elongated bluish spots giving stripe-nosed appearance, numerous small bluish spots covering snout, pectoral, pelvic, dorsal, and caudal fins but not central disc on a sandy brown background with darker brown spots of varying sizes covering the disc, tail, fin bases, and fins, sometimes giving the caudal peduncle a striped appearance; outer edges of pectoral- and pelvic-fin margins blue, lateral tail folds white or striped blue and brown; ventral surface white. Nasal lamellae 37–41; upper jaw tooth row count ~60–75; 187–192 post-synarcual centra; 200–205 total vertebral segments; 63–70 total pectoral skeleton radials.

Distribution: Acroteriobatus leucospilus so far has been recorded from off the central Transkei coast (Eastern Cape Province) to the northern KwaZulu-Natal Province (South Africa) and Mozambique. Ebert et al. (2021), based on the examined material, extended its range to Zanzibar and Dar es Salaam, Tanzania (Fig. 13). It is known from 0 to 100 m depth (Compagno et al. 1989; Séret et al. 2016; Weigmann 2016) but seems to be most abundant in depths of around 20 fathoms or 37 m (Wallace 1967).

Simon Weigmann, David A. Ebert and Bernard Séret. 2021. Resolution of the Acroteriobatus leucospilus Species Complex, with A Redescription of A. leucospilus (Norman, 1926) and Descriptions of Two New western Indian Ocean Species of Acroteriobatus (Rhinopristiformes, Rhinobatidae). Marine Biodiversity. 51, 58. DOI: 10.1007/s12526-021-01208-6

[Ichthyology • 2020] Rhynchobatus mononoke • A New Species of Wedgefish (Rhinopristiformes: Rhinidae) from Japan, with Comments on Rhynchobatus laevis (Bloch and Schneider 1801)

Rhynchobatus mononoke  

Koeda, Itou, Yamada & Motomura, 2020

モノノケトンガリサカタザメ ||  DOI: 10.1007/s10228-020-00777-z   

Abstract

Rhynchobatus mononoke sp. nov. (Rhinopristiformes: Rhinidae) is described from mature male and female specimens from southern Japan. A juvenile specimen, newly born from a captive individual collected from Kagoshima, is also referenced (non-type). The new species can be distinguished from congeners by a combination of its obtusely wedge-shaped snout, bluntly rounded dorsal fins, first dorsal fin originating about level with the pelvic-fin origin, and the outer fold on the spiracle posterior margin more pronounced than the inner fold. Distinctive coloration of the new species included a black blotch, followed by a single white spot (rarely absent) posterodorsally on the middle of the pectoral disc, and a large black blotch covering the anterior half of the undersurface of snout. Distinct white spots distally on the pectoral disc to the middorsal area were absent. Most previous records of species of Rhynchobatus in Japanese waters were reidentified as Rhynchobatus australiae, except for the records from the northern East China Sea. Rhynchobatus mononoke appears to be endemic to southern Japan.

Keywords: Rhynchobatus australiae, Rhynchobatus djiddensis, Rhynchobatus laevis, Taxonomy, Endemic species, East China Sea, Rays

Fig. 1: Fresh holotype of Rhynchobatus mononoke sp. nov., off Satsumasendai, Kagoshima, Japan. KAUM–I. 80332, 1167 mm TL, male

Photographs of Rhynchobatus mononoke sp. nov. (specimens not retained). Kagoshima:
 ca. 2000 mm TL, captive bred individual.

Rhynchobatus mononoke sp. nov.

(New English name: Japanese Wedgefish; 

new standard Japanese name: Mononoke-tongarisakatazame
モノノケトンガリサカタザメ)

 Rhynchobatus djiddensis (not Forsskål 1775): Yamada et al. 2007: 94, pl. 5–5, (northern East China Sea); Kagoshima City Aquarium Foundation 2008: 32, fig. (Kagoshima, Japan, photograph of freshly captured individual); Kagoshima City Aquarium Foundation 2018: 37, fig. (Kagoshima, Japan, photograph of freshly captured individual).

Fresh paratype of Rhynchobatus mononoke sp. nov., off Nagasaki, Japan. KBF-I 1085, 1295 mm TL, male

Etymology. The specific name of the new species, mononoke - もののけ, means “specter” in Japanese, due to the ventral surface of specimens appearing like a traditional Japanese specter, wearing a triangular white hat (crown) on its forehead. The name is used as a noun in apposition.

 

Keita Koeda, Masahide Itou, Morihiko Yamada and Hiroyuki Motomura. 2020. Rhynchobatus mononoke, A New Species of Wedgefish (Rhinopristiformes: Rhinidae) from Japan, with Comments on Rhynchobatus laevis (Bloch and Schneider 1801). Ichthyological Research. DOI: 10.1007/s10228-020-00777-z  

「もののけ」が世に出ました

kuroshio.or.jp/「もののけ」が世に出ました/

Ray at Kagoshima aquarium revealed as new species

 japantimes.co.jp/news/2020/09/27/national/ray-kagoshima-new-species

[Ichthyology • 2016] Rhynchobatus cooki • A New Species of wedgefish Rhynchobatus (Rhinopristiformes, Rhinidae) from the Indo–West Pacific

Rhynchobatus cooki 

Last, Kyne & Compagno, 2016

 DOI:  10.11646/zootaxa.4139.2.7 

Abstract

A new dwarf wedgefish, Rhynchobatus cooki sp. nov. is described from a single female from a Jakarta fish market (Indonesia) and 11 specimens collected at Jurong fish market (Singapore). First collected in 1934, the broader ichthyological community have been aware of this distinctive but little known ray since the late 1990’s. Rhynchobatus cooki is the smallest of the wedgefishes (to 81 cm TL) and has the lowest vertebral count (fewer than 107 centra). It is also distinguishable from its congeners based on its long, hastate snout, very strongly undulate anterior pectoral-fin margin, coloration and aspects of its squamation. The dorsal coloration is mainly dark and distinctively marked with white blotches, spots and streaks, and has a dark cruciate marking on the interorbit and a prominent white border around the body margin. Unlike most other wedgefish species, the snout tip lacks dark blotches and there is no black pectoral-fin marking. It shares well-developed rostral spines with a much larger Atlantic species (Rhynchobatus luebberti), but these spines are confined to the snout tip (rather than being more numerous and extending in paired rows along the rostral ridges nearly to the eyes). No additional specimens have been observed since 1996, despite an increased recent effort to survey the chondrichthyan fauna of South-East Asia and collect biological data for species, raising concerns over its conservation status.

Keywords: Pisces, Rhinidae, Rhynchobatus cooki, Clown Wedgefish, new species, Western Pacific

Peter R. Last, Peter M. Kyne and Leonard J.V. Compagno. 2016. A New Species of wedgefish Rhynchobatus cooki (Rhinopristiformes, Rhinidae) from the Indo–West Pacific. Zootaxa. 4139(2); DOI:  10.11646/zootaxa.4139.2.7

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