Squalus shiraii

VIANA & DE CARVALHO, 2020


Shirai’s spurdog
Classification: Elasmobranchii Squaliformes Squalidae

Reference of the original description
VIANA, S.T.F.L. & DE CARVALHO, M.R. (2020)
Squalus shiraii sp. nov. (Squaliformes, Squalidae), a new species of dogfish shark from Japan with regional nominal species revisited. Zoosystematics and Evolution, 96 (2): 275-311

Types
Squalus shiraii
Holotype: HUMZ: 149389; Paratype: HUMZ: 80329; HUMZ: 80330; HUMZ: 80331; HUMZ: 101718; HUMZ: 146165; HUMZ: 149391; HUMZ: 149392; HUMZ: 149394; HUMZ: 149395; HUMZ: 149426; HUMZ: 149434; HUMZ: 149438;


Description :


Citation: Squalus shiraii VIANA & DE CARVALHO, 2020: In: Database of modern sharks, rays and chimaeras, www.shark-references.com, World Wide Web electronic publication, Version 03/2021

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Squalus shiraii sp. nov.: lateral (A–C) and ventral (D, E) views; first (F) and second (G) dorsal fins; pectoral (H) and caudal (I) fins. HUMZ 149389 (holotype), adult male, 590 mm TL (A, D, F–I); HUMZ 80329 (paratype), adult female, 770 mm TL (B); HUMZ 80330 (paratype), juvenile male, 365 mm TL (C, E). Scale bars: 50 mm (A–E); 20 mm (F–I) © Viana & de Carvalho (2020)
Common names
eng Shirai’s spurdog, Hiretaka-tsunozame (jap)

Short Description
Diagnosis after VIANA & DE CARVALHO, 2020 [28564]: Single values correspond to the holotype and range to paratypes, respectively. A Squalus species that is separated from its regional congeners by: first dorsal fin conspicuously upright (vs. first dorsal fin prone); pectoral-fin posterior margin falcate (vs. not falcate); upper and lower caudal lobes markedly slender with dorsal and ventral caudal tips pointed and broadly white (vs. upper and lower caudal lobes wide with dorsal and ventral caudal tips rounded and greyish in colour); dermal denticles lanceolate, except for S. brevirostris (vs. tricuspidate); smaller claspers with clasper outer length 3.3%, 3.3%–3.4% TL and clasper inner length 6.3%, 5.9%–6.3% TL (vs. 4.5%–4.9% TL, 6.9%–8.4% TL for S. mitsukurii vs. 4.8%, 4.3%–5.6% TL and 7.5%, 7.2%–9.1% TL for S. japonicus; vs. 3.9%, 3.9%–5.1% TL and 7.1%, 7.0%–8.1% TL for S. brevirostris). Squalus shiraii sp. nov. further differentiates from S. mitsukurii by more elongate eyes, its length 4.9%, 4.4%–4.9% TL (vs. 3.6%, 3.1%–4.0% TL) and smaller fifth gill slit, its length 1.7%, 1.7%–2.1% TL (vs. 2.3%, 2.2%–2.6% TL). It is separated from S. japonicus and S. brevirostris by prenarial length 5.5%, 5.4%–5.6% TL (vs. 5.9%, 5.9%–6.8% TL for S. japonicus vs. 4.0%, 3.8%–4.3% TL for S. brevirostris) and width of first dorsal-fin spine 0.9%, 0.9%–0.9% TL (vs. 0.7%, 0.5%–0.8% TL for S. japonicus vs. 0.7%, 0.5%–0.7% TL for S. brevirostris). Squalus shiraii sp. nov. further differs from S. japonicus by shorter snout, its preorbital length 7.9%, 7.4%–7.9% TL (vs. 8.7%, 8.7%–9.3% TL for S. japonicus), smaller preoral length 10.4%, 9.4%–10.4% TL (vs. 10.7%, 10.7%–12.2% TL), larger first dorsal fin, its base length 7.7%, 7.7%–8.7% TL and first dorsal-fin posterior margin length 9.2%, 9.0%–9.3% TL (vs. 6.7%, 6.6%–7.5% TL and 7.8%, 6.7%–8.6% TL for S. japonicus) and wider pectoral fin, its posterior margin length 10.0%, 10.0%–11.7% TL (vs. 8.6%, 7.8%–9.2% TL). It is separated from S. brevirostris by wider internarial space, its width 4.8%, 4.1%–4.8% TL (vs. 3.6%, 3.4%–3.8% TL for S. brevirostris), smaller second dorsal fin with inner margin length 3.6%, 3.2%–4.1% TL (vs. 5.0%, 4.8%–5.7% TL), shorter pectoral-fin inner margin, its length 7.3%, 7.3%–8.3% TL (vs. 10.3%, 9.8%–11.2% TL) and narrower caudal fin, its width at caudal fork 6.4%, 5.7%–6.4% TL (vs. 6.6%, 6.6%–7.3% TL). Squalus shiraii is distinguished from S. formosus regardless of maturity by having more elongate precaudal (78.3%, 78.6%–80.5% TL), pre-second (60.5%, 61.1%–63.4% TL) and pre-first (30.5%, 29.6%–31.2% TL) dorsal length (vs. 77.6%–78.3% TL, 59.4%–59.7% TL and 28.1%–29.0% in S. formosus).

Distribution
endemic, in the shallow waters of the upper continental slope off Southern Japan in the North-western Pacific Ocean [28564]

Size / Weight / Age
TL (max): 770 mm; TL (birth): ? [28564]

Habitat
marine, depth range: 310–390 m [28564]

Dentition
Teeth similar in both jaws; upper teeth smaller than lower teeth; teeth with cusp oblique, thick and small; mesial cutting edge slightly convex; distal heel rounded; mesial heel notched; apron short and heavy (Fig. 3A, B). Two and two to three series of functional teeth in the upper and lower jaws, respectively, 13–14 for holotype (13–14 for paratypes) teeth rows on upper jaw and 11–11 (11–12) teeth rows on lower jaw. [28564]

Remarks
shark-references Species-ID=15952;