Squalus
Creators: name: De, Sarah T.
name: De, Marcelo R.
name: Gomes, Ulisses L.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Squaliformes
Squalidae
Squalus

description: Key to species of Squalus from the Southwestern Atlantic Ocean
1a. First dorsal spine placed well behind vertical line traced at adpressed pectoral free rear tips; white spots dorsally on body; unilobed anterior margin of nostrils; pectoral girdle with anterolateral segmented processes................... S. acanthias.
1b. First dorsal spine placed over or before vertical line traced at adpressed pectoral rear tips; body uniformly colored dorsally; bilobed anterior margin of nostrils; pectoral girdle without any segmented processes............................... 2.
2a. Prenarial length smaller than distance between nostril and upper labial furrow; upper caudal lobe very narrow; pectoral fins very narrow with pectoral free rear tips pointed and angular; caudal fin mostly white; dermal denticles unicuspid and lanceolate; dorsal terminal cartilage (claw) short, thick and straight at tip; accessory terminal cartilage (spur) broad and small.............................................................................................. S. albicaudus.
2b. Prenarial length greater than distance between nostril and upper labial furrow; upper caudal lobe broad and rectangular; pectoral fins broad with pectoral free rear tips rounded and lobe-like; caudal fin grayish; dermal denticles tricuspid and rhomboid; dorsal terminal cartilage (claw) very elongate, slender and hook-like at tip; accessory terminal cartilage (spur) thin and large.................................................................................................... 3.
3a. Body robust and markedly humped dorsally; first dorsal fin conspicuously slender only from its midline to apex; second dorsal fin upright and markedly tall (height 4.0%–5.3% TL); dermal denticles markedly imbricate and broad at crown...................................................................................................... S. quasimodo.
3b. Body very slender throughout, without a dorsal hump; first dorsal fin uniformly slender; second dorsal fin raked and low (height 3.7%–4.4% TL); dermal denticles not imbricate and very narrow.......................................... 4
4a. First and second dorsal fins very broad; caudal fin dark gray with dorsal caudal margin light gray and ventral caudal lobe uniformly dark gray; interdorsal space 21.9%–24.1% TL; dorsal caudal space 10.4%–10.9% TL; pectoral-caudal space 20.3%– 24.4% TL in adults; pectoral inner margin 9.2%–10.6% TL........................................... S. lobularis.
4b. First and second dorsal fins narrow; caudal fin light gray with dorsal caudal margin white and ventral caudal lobe mostly white; interdorsal space (24.4%–26.8% TL); dorsal-caudal space 11.0%–12.2% TL; pectoral-caudal space 19.5%–20.3% TL; pectoral inner margin 8.4%–8.9% TL........................................................... S. bahiensis.
description: Published as part of De, Sarah T., De, Marcelo R. & Gomes, Ulisses L., 2016, Taxonomy and morphology of species of the genus Squalus Linnaeus, 1758 from the Southwestern Atlantic Ocean (Chondrichthyes: Squaliformes: Squalidae), pp. 1-89 in Zootaxa 4133 (1) on page 83, DOI: 10.11646/zootaxa.4133.1.1, http://zenodo.org/record/400024