Common names
Smith’s dogfish shark

Short Description
Original Diagnosis of VIANA, LISHER & DE CARVALHO, 2017 [25216]: A short-snouted species of Squalus from the eastern Atlantic Ocean distinct from its regional congeners (except S. acutipinnis) by having broad pectoral fins that transcend trunk height when adpressed on body (length of pectoral fin anterior margin 16.5%, 15.9–17.9% TL). Squalus margaretsmithae sp. nov. can be separated from S. chloroculus, S. edmundsi, S. lalannei, S. mitsukurii, S. montalbani, and S. nasutus by a smaller snout with prenarial length shorter than distance from nostril to upper labial furrow, and unicuspid and lanceolate dermal denticles (vs. prenarial length greater than distance from nostril to upper labial furrow, and tricuspid and rhomboid dermal denticles). Squalus margaretsmithae sp. nov. is differentiated from S. megalops and S. brevirostris by having postventral caudal margins not uniformly white (vs. postventral caudal margins uniformly white in S. megalops and S. brevirostris). It is separated from S. megalops and S. mahia by having dermal denticles wide at the crown (vs. dermal denticles slender at crown in S. megalops and S. mahia). Squalus margaretsmithae sp. nov. is separated from S. brevirostris and S. crassispinus by shorter dorsal-caudal space (11.2%, 10.8–12.2% TL vs. 10.1– 10.6% for S. brevirostris and vs. 9.9–10.0% TL for S. crassispinus), and from S. mahia and S. crassispinus by prespiracular length (11.5%, 11.7–12.3% of TL vs. 12.4%, 12.4–13.9% TL for S. mahia and vs. 12.5–12.7% TL for S. crassispinus). Squalus margaretsmithae sp. nov. is further differentiated from S. crassispinus by its shorter preorbital length (6.5%, 6.4–7.0% TL vs. 7.3–7.4% TL for S. crassispinus), larger pectoral fins (pectoral fin inner margin length 9.7%, 9.2–10.6% TL vs. 8.6% TL for S. crassispinus; pectoral fin posterior margin length 11.3%, 11.8–14.5% TL vs. 9.0–9.4% TL for S. crassispinus), greater pre-first dorsal fin length (28.2%, 28.1–32.2% TL vs. 26.7–27.4% TL for S. crassispinus), wider mouth (mouth width 7.6%, 7.8–9.0% TL vs. 7.4% TL for S. crassispinus), and shorter pelvic-caudal distance (25.1%, 24.9–27.2% TL vs. 27.9–28.1% TL for S. crassispinus). Squalus margaretsmithae sp. nov. is distinguished from S. acutipinnis by the following: first dorsal fin somewhat upright and rounded at apex, its posterior margin concave at its midline (vs. first dorsal fin prone and pointed at apex, its posterior margin straight throughout in S. acutipinnis); caudal fork between lobes discontinuous (vs. continuous in S. acutipinnis); dermal denticles with length greater than width and symmetrical lateral expansions (vs. dermal denticles somewhat equal in length and width, and asymmetrical lateral expansions in S. acutipinnis); upper teeth narrow, lower teeth depressed, cusp very short and somewhat oblique, straight mesial cutting edge, rounded mesial heel, and apron very short in both jaws (vs. upper teeth broad, lower teeth tall, cusp elongate and directed upward, concave mesial cutting edge, constricted mesial heel, and apron shorter only in upper teeth in S. acutipinnis).

Distribution
eastern Atlantic Ocean from Portugal and Morocco to South Africa [25216]

Size / Weight / Age
312.0–475.0 mm TL [25216]

Habitat
marine; depth range 55-460 [25216]

Dentition
Teeth similar in both jaws, labial-lingually flattened, unicuspid; upper teeth smaller than lower teeth; cusp very short and somewhat oblique; mesial cutting edge straight; mesial and distal heels rounded; apron very small and thick. Two series of functional teeth on both upper and lower jaws in holotype; tooth rows 13–13 in upper jaw and 11–11 rows in lower jaw in holotype [25216]

Remarks
shark-references Species-ID=14876;