Squalus acutipinnis

REGAN, 1908

Bluntnose spiny dogfish
Classification: Elasmobranchii Squaliformes Squalidae

Reference of the original description
REGAN, C.T. (1908)
A collection of fishes from the coasts of Natal, Zululand, and Cape Colony. Annals of the Natal Museum, 1 (3): 241–255, pl. 37–42

Image of the original description

Squalus acutipinnis REGAN, 1908 (image of the first description)

Squalus acutipinnis
Lectotype: BMNH: 1905.6.8.8; Paralectotype: BMNH: 1900.11.6.14; BMNH: 1859.5.7.68; BMNH: 1881.3.11.2;

Description :

Citation: Squalus acutipinnis REGAN, 1908: In: Database of modern sharks, rays and chimaeras, www.shark-references.com, World Wide Web electronic publication, Version 06/2019

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Lateral view of Squalus acutipinnis, SAIAB 19863, female, 570 mm TL from Port Alfred, South Africa; © VIANA, S.T. & DE CARVALHO, M.R.
Common names
eng Bluntnose spiny dogfish, Stompneus-penhaai (Afrikaans)

Short Description
Original diagnosis after REGAN, 1908 [10390]: Snout pointed; nasal flaps bilobed; distance from nostrils to end of snout 2/3—3/4 that from mouth to nostrils. Base of second dorsal (without the spine) \ of its distance from the upper caudal lobe and h that of the first (without the spine), which is less than its height and about 2/9 of its distance from the second dorsal ; spines without ridges or grooves, that of the second dorsal not quite so high as the fin, in great part exposed. Pectoral extending well beyond the end of the base of first dorsal and at least 2/3 of the distance from last gill-opening to origin of ventral, with the free edge nearly straight, the posterior angle nearly a right angle and the anterior angle much more acute than in S. blainvillii; ventrals not nearly reaching the second dorsal. Lower caudal lobe without posterior notch, its lower edge continuous with the posterior edge of the upper lobe. (Grayish or brownish above, pale below).
Diagnosis of the Redescription after DE F. VIANA & DE CARVALHO, 2016 [24214]: A species of Squalus mostly from the Western Indian Ocean diagnosed by the following combination of characters: snout rounded and short (preorbital snout length 6.3% for lectotype, 6.5–7.1% TL for non-type material), prenarial snout length 0.8 (0.9–1.0) times inner nostril-labial furrow space; first dorsal fin upright, triangular in shape and low (8.2%, 8.0–9.3% TL); pectoral fins markedly broad with posterior margin conspicuously greater than trunk height when adpressed on body; and caudal fin with narrow dorsal lobe and continuous caudal fork between lobes. Squalus acutipinnis can be distinguished from all species of the S. megalops-cubensis group (except from S. megalops, S. brevirostris, and S. crassispinus) by fewer total (108, 107–111 [mode 109, n¼10] vs. 113–125), precaudal (81, 81–83 [mode 82, n ¼ 10] vs. 84–96), and monospondylous vertebrae (41, 37–42 [mode 40–41, n ¼ 10] vs. 41–49). Squalus acutipinnis differs from S. megalops from Southern Australia by having a rounded snout (vs. pointed snout), L-shaped free rear tips of pectoral fins and pectoral fins not lobe-like (vs. evidently rounded and lobe-like pectoral fins), triangular first dorsal fin (vs. rounded first dorsal fin at tip), pectoral fins transcending trunk height when adpressed on body (vs. pectoral fins, never reaching trunk height), shorter prespiracular length (11.6%, 7.7–12.1% TL vs. 13.5%, 11.6–13.4% TL), more elongated first dorsal spine (3.5–4.3% TL vs. 1.8–3.6% TL), dermal denticles broad at crown with length equal to width (vs. dermal denticles slender at crown with length much greater than width), and margins of pectoral and caudal fins white but not uniform (vs. evident uniform white margins). Squalus acutipinnis further differs from S. brevirostris from Japan by having pectoral fins with L-shaped free rear tips and not lobe-like, and with straight posterior margin (vs. pectoral fins triangular and with pointed free rear tips, lobe-like and with strongly concave posterior margin), length of pectoralfin anterior margin 1.8 (1.5–1.9) times greater than length of its inner margin (vs. length of pectoral-fin anterior margin 1.4, 1.2–1.5 times greater than its inner margin length), and length of first dorsal-fin posterior margin relatively greater 9.6%, 8.8–10.3% TL (vs. 7.7%, 8.3–8.8% TL). The Southern African species is also clearly distinct from S. crassispinus by narrower first and second dorsal spines (first dorsal spine base width 0.6%, 0.6–0.9% of TL vs. 1.3%, 1.2–1.3% of TL; second dorsal spine base width 0.6%, 0.7–1.0% of TL vs. 1.5%, 1.3– 1.4% of TL).

Western Indian Ocean, Kwazulu-Natal to Algoa Bay in the Eastern Cape (South Africa) and Mauritius, There are few records from the Atlantic side of South Africa but without occurrences to the north-northwest of Cape Town [24214]

Size / Weight / Age
310-695 mm TL [24214]

marine [24214]

Unicuspid teeth similar in both jaws, labial-lingually flattened and alternate, broad at crown; teeth broader in lower jaw than in upper jaw; cusp robust and slightly elongated, diagonal and upwardly directed; mesial cutting edge concave; distal heel markedly rounded; slender mesial heel; apron short in upper teeth and more elongated in lower teeth; lectotype with three series of functional teeth in upper jaw and two series in lower jaw; tooth row formula 13/11 [24214]

shark-references Species-ID=6689;

Parasites (arranged by Jürgen Pollerspöck)