Bythaelurus vivaldii

WEIGMANN & KASCHNER, 2017



Classification: Elasmobranchii Carcharhiniformes Pentanchidae

Reference of the original description
WEIGMANN, S. & KASCHNER, C.J. (2017)
Bythaelurus vivaldii, a new deep-water catshark (Carcharhiniformes, Scyliorhinidae) from the northwestern Indian Ocean off Somalia. Zootaxa, 4263 (1): 97–119

Types
Bythaelurus vivaldii
Holotype: ZMB: 17410; Paratype: ZMB: 22423;

Images of types

Description :


Citation: Bythaelurus vivaldii WEIGMANN & KASCHNER, 2017: In: Database of modern sharks, rays and chimaeras, www.shark-references.com, World Wide Web electronic publication, Version 03/2021

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Bythaelurus vivaldii WEIGMANN & KASCHNER, 2017 © Dr. Simon Weigmann, Elasmobranch Research Laboratory, Lüneburg
Common names
eng Vivaldi’s Catshark

Short Description
Original Diagnosis of WEIGMANN & KASCHNER, 2017 [25300]: A supposedly very small scyliorhinid species with the following characteristics: body firm and stout in presumably adult holotype (slender in supposedly juvenile paratype); snout long (preorbital length 6.1– 6.6% TL) and broad, bell-shaped in dorsoventral view with distinct lateral indention; pre-outer nostril length subequal to internarial space; preorbital snout length subequal to interorbital space; preoral snout length 1.4–1.8 times in mouth width; eye length 13.9–15.0 times in predorsal distance, 6.8–6.9 times in head length and 1.6–2.3 times eye height; head length 2.6–2.8 times width at level of maximum outer extent of anterior nostrils; head width at level of maximum outer extent of anterior nostrils 1.2 times width at level of lateral indention of head, 1.3–1.4 times preorbital length, and 8.5–8.6% TL; roof of mouth loosely set with rather small, knob-like to elongated oral papillae, oral papillae on tongue hardly detectable; pelvic-fin anterior margin 2.0–2.1 times in pectoral-fin anterior margin; first dorsal-fin base 2.2–2.3 times in interdorsal space; length of second dorsal-fin inner margin 1.3–2.3 times in second dorsal-fin height; second dorsal-fin base length 5.3% TL; anal-fin base 0.7–0.8 times interdorsal space. Coloration: reported to have 8–9 dark, broad but inconspicuous transverse bars on the back, but preserved coloration plain beige with scattered remains of dark brown. Upper jaw with 68–75 and lower jaw with 64 rows of small tri- to pentacuspidate teeth with outer surface of crown furrowed by strong longitudinal ridges from base of cusps to tip and strongly structured by reticulations from basal areas to well into cusps; monospondylous trunk vertebrae centra 38, diplospondylous precaudal centra 43–44, total centra about 135–140. Dermal denticles leaflike to teardrop-shaped on snout and tricuspidate on trunk and tail. The new species is distinguished from all congeners in the western Indian Ocean by a larger pre-second dorsal fin length, a longer head, a larger interdorsal space, a larger intergill length, a longer pectoral-fin posterior margin, a shorter caudal fin, an intermediate caudal fin preventral margin, and a larger internarial width.

Distribution
Known only from the upper slope off Somalia, 6°24'1" N, 49°31'6" E, in 628 m depth (types) [25300]

Size / Weight / Age
maturing at around 30 cm TL and probably attaining about 35 cm TL [25300]

Habitat
marine; depth range: 628 m depth (types) [25300]

Dentition
Upper jaw with 68 (about 75) and lower jaw with 64 (not counted due to jaw damage) diagonal rows of small teeth. Anterolateral teeth in upper jaw tricuspidate, partially with small additional cusplets, with median cusp much longer than lateral cusps; posterolateral teeth in upper and lower jaws tri- to pentacuspidate and with median cusp only slightly longer than lateral cusps. Anterolateral teeth in lower jaw (Figure 8, C–D) similar to posterolateral teeth. Outer surface of crown furrowed by strong longitudinal ridges from base of cusps to tip and strongly structured by reticulations from basal areas to well into cusps. Cutting edges of cusps without serrations [25300]

Remarks
shark-references Species-ID=14879;