Squalus probatovi

MYAGKOV & KONDYURIN, 1986



Classification: Elasmobranchii Squaliformes Squalidae

Reference of the original description
MYAGKOV, N.A. & KONDYURIN, V.V. (1986)
Dogfishes Squalus (Squalidae), of the Atlantic Ocean and comparative notes on the species of this genus from other regions. Journal of Ichthyology, 27 (1): 1–18

Types
Squalus probatovi
Holotype: ZMMU: P-15991;


Description :


Citation: Squalus probatovi MYAGKOV & KONDYURIN, 1986: In: Database of modern sharks, rays and chimaeras, www.shark-references.com, World Wide Web electronic publication, Version 03/2021

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Common names
eng Southern dogfish

Short Description
Diagnosis after VIANA & DE CARVALHO, 2018 [26765]: A medium size African species of Squalus that differs from its regional congeners by having origin of first dorsal fin located over vertical traced at origin of pectoral fins (vs. posterior to origin of pectoral fins), and dorsal fins upright and slender at fin web (vs. prone and broad at fin web, except for S. mahia). Squalus probatovi is clearly separated from S. acanthias, S. acutipinnis, S. mahia, S. margaretsmithae, and S. blainvillei by having body bluish dark grey dorsally (vs. light grey with white spots in S. acanthias vs. grey in S. mahia vs. brown in S. acutipinnis and S. margaretsmithae vs. reddish brown in S. blainvillei), prenarial length greater than inner nostril-labial furrow space (vs. prenarial length smaller than inner nostril-labial furrow space, except for S. acanthias), and dermal denticles tricuspid and rhomboid (vs. denticles unicuspid and lanceolate). It is distinct from S. acutipinnis S. mahia and S. margaretsmithae by having pectoral free-rear tips rounded (vs. pointed and triangular in S. mahia vs. pointed and L-shaped in S. acutipinnis and S. margaretsmithae), and from S. acutipinnis and S. margaretsmithae by bearing narrow pectoral fins, never reaching the trunk height when adpressed on body (vs. pectoral fins wide, conspicuously transcending the trunk height). Squalus probatovi differs from S. mahia by pectoral-fin posterior margin straight, lower caudal lobe dark grey and absence of black caudal blotch (vs. pectoral-fin posterior margin concave, lower caudal lobe whitish and black caudal blotch present near lower caudal origin in S. mahia). Squalus probatovi is distinct from S. bassi by showing origin of second dorsal fin located behind vertical traced at pelvic- fin free rear tips in adults (vs. over vertical traced at pelvic-fin free rear tips in adults), and caudal with post-ventral caudal margins uniformly white, ventral caudal tip conspicuously white and preventral caudal margin white (vs. post-ventral caudal margins not uniformly white, ventral caudal tip slightly white, preventral caudal margin dark brown). It is further separated from S. acanthias by having nostrils bilobed and segmented processes of scapulae absent (vs. nostrils unilobed, segmented process of scapulae present). Squalus probatovi has more monospondylous vertebrae (45–48) than S. mahia (39–42), S. acutipinnis (37– 42), and S. margaretsmithae (38–43), and more precaudal vertebrae (87–96) than S. lalannei (67–69), S. mahia (80–84), S. acutipinnis (81–83), S. margaretsmithae (80–85), and S. acanthias (75–78). It is further distinguished from all regional congeners (except S. bassi) by total vertebrae (118–124) (vs. 93–95 for S. lalannei vs. 107–112 for S. mahia vs. 107–111 for S. acutipinnis vs. 107–115 for S. margaretsmithae vs. 104–107 for S. acanthias). Adult specimens of S. probatovi are separated from those of the Mediterranean S. blainvillei by smaller second dorsal-fin spine, never transcending second dorsal-fin apex, its length 4.5–5.6% TL (vs. 6.3–7.3% TL in S. blainvillei, always transcending dorsal-fin apex), broader internarial space 4.2–5.2% TL (vs. 3.3–3.8% TL in S. blainvillei), larger spiracle, its length 1.4–1.9% TL (vs. 1.2–1.3% TL in S. blainvillei), more elongate first dorsal fin, its length 13.9– 15.9% TL (vs. 13.5%–13.8% TL in S. blainvillei), wider head, its width at nostrils 7.2–8.3% TL in S. probatovi (vs. 6.6–7.1% TL in S. blainvillei), and body much more deep, its heights at head 9.9–11.3% TL and at trunk 9.8–12.9% TL in S. probatovi (vs. 9.0– 9.8% TL, 9.4–9.7% TL in S. blainvillei, respectively)

Distribution
North and South Eastern Atlantic Oceans from Ghana to Angola, Western Indian Ocean in waters surrounding South Africa, Mozambique and Madagascar [26765]

Biology
Two to four pups per litter are usually recorded [26765]

Size / Weight / Age
TL (max) females: 790 mm, males: 677 mm. [26765]

Habitat
demersal; marine; depth range 56 - 503 m [26765]

Dentition
Teeth unicuspid with cusp thick, oblique and short; teeth similar and equal in length in both jaws; mesial cutting edge straight; mesial heel notched; distal heel rounded; apron markedly thin and short, placed more medially at crown. Two to three series of functional teeth on upper and lower jaws. Upper jaw with 13–14 teeth rows; lower jaw with 11–12 teeth rows. [26765]

Remarks
shark-references Species-ID=7991;