Scyliorhinus stellaris (Linnaeus, 1758)

(Figs. 70–76, Tabs. 3, 9, 16)

Common names: Large spotted dogfish, Larger spotted dogfsh, Greater spotted dogfsh, Nurse hound, Bull huss, Spotted dogfsh (United Kingdom); Le squale rochier, Chat rochier, Rousette a grandes taches, Panthêre de mer, Cat rouquiera, Pinto reussou, Vache (France); Pantherhai, Hundshai, Grossgefleckter Katzenhai (Germany); Grote gevlekte hondshaai (Netherlands); Bounce (Belgium); Bruxa, Cacåo, Carraca, Cascarra, Gata, Bata roxa, Pata roxa denisa (Portugal); Alitán, Gat, Gatet, Gato, Gaton, Muxina, Pintarroja (Spain).

Squalus stellaris Linnaeus, 1758:235 (original description, type locality: Mediterranean Sea); Houttuin, 1764: 508 –509 (compilation); Linnaeus, 1766: 399 (compilation); Berkenhout, 1769: 36 (catalogue, Great Britain and Ireland); Heppe, 1787: 212 (compilation); Bonnaterre, 1788: 7 (compilation); Duperrey, 1830: 83 (catalogue, expedition ‘La Coquille’); Lacépède, 1830: 384–387 (compilation).

Scyllium stellaris: Risso, 1826:116 (catalogue, Southern Europe); Jenyns, 1835: 496 –497 (catalogue, United Kingdom).

Catulus saxatilis: Valmont, 1769: 51 (listed).

Scyllium catulus: Cuvier, 1817: 124 (compilation); Cuvier, 1829: 386 (compilation); Cuvier et al., 1834: 586 (brief account, classification); Partington, 1837: 651 (compilation); Parnell, 1838: 407 –409 (catalogue, North Sea); Müller & Henle, 1838 –41: 9–11 (brief description, systematics of Elasmobranchii); Gosse, 1851: 310 (compilation); Hamilton, 1854: 300 - 301 (compilation); Duméril, 1865: 316 –318 (compilation); Bocage & Capello, 1866: 11 (catalogue, Portugal); Moreau, 1881: 280 –284, fig. 36 (catalogue, France); Day, 1884: 312–314, fig. 2, pl. 159 (catalogue, Great Britain and Ireland); Gordon, 1902: 135 (catalogue, Great Britain); Coward, 1910: 161 (catalogue, Cheschire and Liverpool Bay); Leigh- Sharpe, 1920: 247–251, fig.1 (clasper description) [synonymy follows Springer 1973:19].

Scyllium stellare: Fleming, 1828:165 (catalogue, United Kingdom); Schinz, 1840: 461 (catalogue, Europe); Thompson, 1856: 247 (listed); Günther, 1870: 403 (catalogue, British Museum); Doderlein, 1880: 22–24 (catalogue, Mediterranean Sea); Balfour, 1881: 656 –671 (anatomy and development of paired fins); Faber, 1883: 181 –182 (catalogue, Adriatic Gulf); Jungersen, 1899: 34 –36, pl. II, figs. 16-18. VI, figs. 65, 66 (clasper description); Danois, 1913: 15, figs. 4, 8 (compilation).

Scylliorhinus stellaris: Blainville, 1830:71, pl. 17 (listed, classification).

Catulus stellaris: Hoffman & Jordan, 1892: 233 (catalogue, Greece); Garman, 1913: 75 –76 (brief account).

Scyliorhinus stellaris: Regan, 1908: 457 (brief account); Ford, 1921: 492 –493 (diet); Bigelow & Schroeder, 1948: 203 (catalogue, comparison with species of Northwestern Atlantic); Tortonese, 1956: 130, figs. 66–69 (catalogue, Italy); Wheeler, 1969: 44, fig. 15 (catalogue, British Islands); Springer, 1973: 19 (listed, Northeastern Atlantic and Mediterranean Sea); Springer, 1979: 143 –144, figs. 3, 94 (taxonomic review); Cadenat & Blache, 1981: 178 –181, figs. 121b, 122 (except part referring to specimens of S. cervigoni); Compagno 1984; 366–367 (FAO catalogue); Compagno, 1999: 480 (listed); Soldo et al., 2000: 355 –356 (tooth morphology); Compagno et al. 2005: 252, pl. 41 (compilation); Serena, 2005: 38, pl. IV, 31 (FAO catalogue, Mediterranean Sea); Capapé et al., 2006: 29 –36 (reproductive biology); Fricke et al., 2007: 13 (listed); George, 2009 (listed, North Sea): 35; Ebert et al. 2013a: 372, 383, pl. 51 (compilation); Ebert & Stehmann, 2013: 211 –2012, figs. 242, 243 (egg capsules); Sabata & Clò, 2013: 178 –179 (reproductive biology); Bilecenoglu et al., 2014: 904 (catalogue, Turkey); Gordon et al., 2016: 272 –273, fig. 8c (egg capsules); Weigmann, 2016: 44 (listed).

Haploblepharus stellaris: White, 1937: 121 (listed, systematics).

Scyllium (Betascyllium) catulus: Leigh-Sharpe, 1924: 325 (clasper description, classification).

Scyllium (Betascyllium) stellare: Leigh-Sharpe, 1924: 326 (clasper description, classification).

Neotype. NHMUK 1976.7.30.10, male, 476 mm TL ( Banyuls, Pyrenees, France) [designated herein].

Additional material examined. 98 specimens (see Appendix).

Diagnosis. Scyliorhinus stellaris differs from all congeners by presenting a mesonarial ridge extending posteriorly beyond the posterior border of anterior nasal flap (vs. not exceeding it in all other species); pelvic fins trapezoidal (vs. subtriangular in other species, except S. garmani and S. torazame); color pattern composed of dark spots with well-defined borders and predominantly greater than spiracles (vs. dark spots absent in S. capensis, S. comoroensis, S. hesperius, S. meadi, S. torazame, and S. torrei; reticulated pattern in S. retifer; dark spots predominantly smaller than spiracle in S. boa and S. cabofriensis; spots scattered, diffuse in S. duhamelii). The following combination of characters, although less conspicuous, also helps distinguish this species: spots scattered along the dorsolateral surface (vs. spots predominantly restricted to saddles in S. boa, S. cervigoni and S. haeckelii); anterior nasal flaps reaching the upper lip (vs. not exceeding in others, except in S. cervigoni, S. comoroensis, S. duhamelii, and S. garmani); distance between anterior nasal flaps two times smaller than width of anterior nasal flap (vs. 6–7.5 times in S. canicula; 3.5–5 times smaller in S. duhamelii); nasoral grooves absent and posterior nasal flaps situated on posterior border of excurrent apertures (vs. grooves present and flaps laterally situated in S. canicula and S. duhamelii); interdorsal distance 0.6–1.0 times the anal base (vs. greater than the anal base in S. boa, S. cabofriensis, S. haeckelii, S. hesperius, S. meadi, S. retifer, S. torrei, and S. ugoi); mandibular canal of lateral line system with 6 or 7 pores (vs. 4–5 in S. duhamelii; 3–4 in S. hesperius); oral canal of lateral line system with 7–10 pores (vs. 5–6 in S. hesperius; 10–12 in S. duhamelii; 9–13 in S. torrei); commissural teeth with two cusplets (vs. one in S. cervigoni, S. torazame and S. torrei; three or more in S. boa, S. canicula and S. hesperius); upper tooth rows 41–51 (vs. 33–42 in S. torrei); lower tooth rows 34–50 (vs. 48–85 in S. capensis); pelvic apron extending to 2/ 3 length of pelvic inner margins (vs. extending through almost pelvic entire length in S. canicula, S. capensis, S. duhamelii, S. torazame, and S. torrei); clasper with terminal dermal cover smooth (vs. rough in S. canicula and S. capensis); cover rhipidion covered by dermal denticles (vs. denticles absent in S. boa, S. cervigoni, S. hesperius, and S. retifer); terminal 3 cartilage absent (vs. present in S. boa, S. canicula, S. capensis, S. retifer, and S. torazame); dorsal terminal 2 cartilage elongated and corresponding to 1/4 of dorsal terminal cartilage (vs. reduced and subtriangular in S. cabofriensis, S. capensis, S. cervigoni, S. haeckelii, and, S. ugoi; 1/3 of dorsal terminal cartilage in S. boa and S. comoroensis; cartilages same length in S. torazame); counts of monospondylous vertebrae 43–47 (vs. lower counts in than S. boa, S. cabofriensis, S. canicula, S. comoroensis, S. duhamelii, S. haeckelii, S. hesperius, S. torazame, and S. torrei; 48 in S. garmani); adult males between 700–740 mm TL and adult females between 770–790 mm TL (vs. adult sizes smaller in other species, except S. capensis, S. cervigoni and S. meadi).

Description. Morphometric and meristic data are given in Table 16, and neurocranial measurements in Table 9.

Body robust, tapering considerably posterior to cloaca (Figs. 70, 71). Prepectoral length 0.5 times the prepelvic length. Trunk shorter than tail; snout-vent length 0.8–0.9 (0.8) times vent-caudal length. Pectoral-pelvic space 1.9–3.1 (2.1) times the pelvic-anal space. Interdorsal space 1.8–2 (1.8) times the dorsal-caudal space (Tab. 16). No interdorsal, postdorsal or postanal ridges; lateral crest on caudal peduncle absent.

......continued on the next page

Head broad and depressed; head length 1.4–1.6 (1.8) times head width (Figs. 70, 71). Snout relatively short, preoral length 0.5–0.7 (0.6) times mouth width and 0.7–0.9 (0.7) times smaller than preorbital length. Prenasal length 0.4–0.6 (0.5) times internarial space; preorbital length 0.8–0.9 (0.8) times interorbital space.

Eye large and slitlike, eye length 2.1–4.5 (2.8) times its height and 0.2 times smaller than head length (Figs. 70, 71). Eye dorsolateral on head, with lower edge medial to horizontal head rim in dorsal view; subocular ridge strong. Nictitating lower eyelid of rudimentary type, with shallow subocular pouch and secondary lower eyelid free from upper eyelid. Spiracle close behind but well separated from eyes, dorsolaterally on head and somewhat lower than level of eye notch. Spiracle diameter goes 2.3–4.5 (3.4) times in eye length and 5.1–8.8 (7.5) times in interorbital distance.

First two gill openings about equally wide; first one twice as long as fifth. All gill openings slightly concave and not elevated on dorsolateral surface of head; gill filaments not visible externally.

Nostril with broad incurrent aperture, without nasoral groove or nasal barbel, and small and oval excurrent aperture. Anterior nasal flap large, triangular, covering posterior nasal flap and excurrent aperture, and touching the upper lip (Figs. 72 A–B). Mesonarial ridge distinct and extending posteriorly beyond the posterior border of the anterior nasal flap. Posterior nasal flap rectangular, situated on the posterior border of the excurrent aperture. Mesonarial superior and inferior flaps conical and corresponding to 1/3 of anterior nasal flap. Internarial space 0.7–0.8 (0.7) times the interorbital space.

Mouth arched, moderately wide and short, its length goes 1.4–1.9 (1.6) times in mouth width (Figs. 72 A–B). Lower labial furrow short and narrow, 2.8–4 (3.9) times smaller than mouth width. Dorsal labial cartilage 1.3 times the ventral cartilage; anterior tip of dorsal labial cartilage reaching the orbital process of the palatoquadrate. Tongue flat and rounded, light-colored, with oral papillae hardly detectable.

Monognathic heterodonty gradual well developed; anterior teeth abruptly larger than the parasymphysial ones and lateral teeth smaller distally, with smaller and thicker principal cusps (Fig. 73). Sexual heterodonty pronounced with females presenting shorter principal cusp and more developed cusplets than males. Tooth counts 20–26 16–25/16–25 0– 1 16–24. Parasymphysial teeth with a principal cusp flanked by one cusplet on each side; cusplets half the height and the width of the principal cusp. Protuberances on medial portion of the crown base and striae restricted to the crown base. Anterior teeth larger than the parasymphysial and principal cusp less stout. Anterior teeth with two to four cusplets; marginal cusplets poorly developed and 1/3 the height of proximal cusplets in upper teeth and poorly developed in lower teeth. Proximal cusplets 1/3 the height and the width of the principal cusp in teeth in both jaws. Protuberances on the crown base and striae extending to one half the height of crown. Lateral teeth with three cusplets; principal cusp slightly oblique, two cusplets at the mesial edge and one at the distal edge. Mesial proximal and distal cusplets one halt to 2/3 the height of the principal cusp; mesial marginal cusplet half the height of proximal one. Protuberances on the crown base and striae running from base toward the apex of the principal cusp. Commissural teeth with two cusplets; principal cusp stronger and laterally situated. Cusplets 2/3 the height and the width of the principal cusp. Protuberances on the crown base and striae throughout the crown. Ectodermal pits present in lateral and commissural teeth, restricted to the crown base.

Lateral trunk denticles with flat, elongated teardrop-shaped crowns, 1.6–1.8 times as long as wide (Tab. 3); anterior part covered with ectodermal pits. Dermal denticles above the pectoral fin presenting five ridges, median ridge less prominent than in denticles of other regions and not extending to the intersection between principal cusp and cusplets. Denticles below dorsal fins longer and with prominent median and lateral ridges, extending to the distal tip of cusplets (Fig. 74).

Pectoral base 0.7–0.8 (0.8) times mouth width (Fig. 72D). Pectoral anterior margin 2.1–2.2 (2.3) times its base and 1.4–1.7 (1.5) times the posterior margin. Pectoral fin skeleton aplesodic with radials mostly divided into three segments. Propterygium and mesopterygium trapezoidal; the former smaller than the latter. Propterygium with one proximal segment; mesopterygium with 3–4 proximal segments fused proximally. Metapterygium with 8–9 segments. Metapterygial axis rectangular and corresponding to 1/4 of metapterygium.

Pelvic fin subrectangular in females and trapezoid in males (Figs. 72 E–F); pelvic anterior margin 1–1.3 (1.1) times the posterior margins and 0.9–1 time the pelvic base. Pelvic inner margins of males fused by 2/3 of their extension; claspers of juveniles evident without lifting the pelvic apron.

Clasper short and cylindrical (Fig. 72F), sometimes extending beyond free rear tips of pelvic fins; clasper inner length 1.4–1.7 (1.3) times the pelvic anterior margin, 1.7–3 (2.4) times the clasper outer length and 3.7–4.8 (4.4) times the clasper base. Most of clasper surface except ventrolateral and dorsomedial surface of glans, rhipidion, and terminal dermal cover, covered by dermal denticles with anteriorly directed crowns (Fig. 75A). Clasper hooks absent. Rhipidion well-developed, partly covered medially by a prominent exorhipidion and anteriorly by the cover rhipidion; insertion of rhipidion at posterior portion of dorsal terminal 2 cartilage and extending to the end of glans. Cover rhipidion expanded medially reaching the exorhipidion, and sometimes covered by this anteriorly; both cover rhipidion and exorhipidion covering the clasper groove. Envelope absent; pseudosiphon distinct and robust. Terminal dermal cover extending for 1/3 of the ventral terminal cartilage, covering the posterior edges of exorhipidion and cover rhipidion.

Clasper skeleton relatively simple (Fig. 75B). Ventral terminal cartilage beginning anteriorly, but ending together with the dorsal terminal. Terminal 3 cartilage absent. Dorsal terminal 2 cartilage elongated and rod-like, medially positioned on the dorsal terminal cartilage; this cartilage supports the rhipidion and corresponds to 1/4 the length of dorsal terminal cartilage. Ventral terminal 2 cartilage slender, above the ventral terminal cartilage, and corresponding to 2/3 of this; ventral terminal 2 cartilage beginning at the same level that dorsal terminal 2.

First dorsal fin subrectangular or triangular, with nearly straight anterior margin, rounded apex and angular free rear tip (Figs. 70, 71). First dorsal fin origin slightly anterior to the pelvic fin insertion. First dorsal fin insertion opposite to the anterior 1/3 of pelvic-anal distance. Anterior margin 1.5 (1.3) times first dorsal fin base; first dorsal fin height 0.8 times its base.

Second dorsal fin triangular and smaller than the first (Figs. 70, 71). Second dorsal fin origin slightly posterior to the anal midbase and insertion opposite to the posterior end of the anal fin. Anterior margin 1.3 times base of second dorsal fin; second dorsal base 1.6–1.8 (1.6) times its height and 0.4–0.6 (0.6) times the dorsal-caudal distance. First dorsal fin 1.3–1.4 (1.4) times larger than the second dorsal fin.

Anal fin rounded, apically narrow and not falcate (Figs. 70, 71); anal fin base 1.6–1.8 (1.6) times the second dorsal fin base. Anal fin anterior margin nearly straight, apex rounded, free rear tip acutely pointed, and inner margin nearly straight. Anal fin base 1.4–2.1 (1.4) times the interdorsal distance and 2–2.2 (2.2) times the dorsalcaudal distance. Anal fin anterior margin 1.8–2.1 (1.8) times the posterior margin; anal fin height 0.3–0.4 (0.4) times its base.

Caudal fin narrow-lobed and asymmetrical (Figs. 70, 71). Dorsal caudal lobe 1.2–1.4 (1.5) times larger than preventral lobe; subterminal caudal margin 0.7–0.8 (0.7) times the terminal margin. Caudal crest of enlarged denticles absent on caudal fin margins.

Neurocranium broad and somewhat flattened, corresponding to 8.9–9.5% TL. Rostrum length 1.4–1.7 times the distance between lateral rostral cartilages. Nasal capsule wider than long, oval-shaped and expanded laterally; width 1.1–1.2 times its length. Basal plate flat with narrow borders, its width 2–2.1 times smaller than nasobasal length. Orbital region 2.5–2.6 times smaller than nasobasal length. Otic capsule short, its length 4.4–4.6 times smaller than nasobasal length and width 2.7–2.8 times otic capsule length. Width across postorbital processes 1.1–1.2 times the preorbital processes width (Tab. 9).

Coloration in alcohol. Body beige with dark brown spots greater than spiracles and distributed along the dorsolateral surface; spots smaller in dorsal regions than in lateral regions (Figs. 70, 71). Lunate and clear center spots present. Longitudinal dorsal stripe extending from level of spiracle to caudal peduncle in some specimens; seven to eight saddles present or absent. Subsaddles between saddles anterior to the first dorsal fin. Juveniles with numerous dark and small spots, usually with light spots, and sometimes saddles distinct in relation to the background. Belly and ventral surface of paired fins with or without dark spots.

Distribution. This species is distributed along the Balearic and Tyrrhenian Seas, in the continental shelves of Italy, Tunisia, France and Spain, with two records in the Adriatic Sea close to Venice, Italy, and Rovinj, Croatia. Also found along the Northeastern Atlantic in the continental shelves of Portugal, France and the United Kingdom, as well as one record for the North Sea (55°N, 3°E). No records exist from northwestern Africa (Fig. 76).

Biological data. Adult males between 700–740 mm TL; largest male examined 956 mm. Adult females between 770–790 mm TL; largest female examined 971 mm TL. Maximum size recorded 1900 mm (Fischer et al. 1987); sizes larger in the northern part of its distribution (up to 1500 mm TL) than in the Mediterranean Sea (750 mm TL) (Tortonese 1956). Egg deposition occurs all year, except in December and January. Embryo development ~9 to 12 months; size of newly born 105–110 mm TL (Ebert & Stehmann 2013; Gordon et al. 2016). Copulatory behavior influenced by the number of males in the environment (Capapé et al. 2006).

Egg capsules dark brown to nut brown. Anterior edge wider and slightly concave; tendrils turned outwards. Posterior edge smaller and more concave; tendrils inward facing and crossed. Longitudinal striae throughout egg length; lateral portion reinforced with transverse striae. Mean values of egg capsule dimensions: 84.4 mm length, 33.6 mm width, and 15.7 mm width. Egg capsules usually incrusted with macroalgae in shallow waters and sessile vertebrates in deeper waters, including Eunicella verrucosa and Cystoseira tamariscifolia (Gordon et al. 2016) .

Stomach contents presenting small fishes, crustaceans and squids; three specimens examined contained S. canicula (Ford 1921; Azouz & Capapé 1971) and a wide variety of bony fishes, including mackerel, herring and codfish (Ebert & Stehmann 2013). This species is a benthic dweller in depths down to 125 m, and is usually found on rock bottoms or substrates with an algae canopy. Conservation status ‘Near Threatened’ (Ellis et al. 2009), with some evidence of population decline in some regions of the Mediterranean Sea (Ebert & Stehmann 2013).

Remarks. The designation of a neotype for S. stellaris, proposed by Fricke (1999), was invalidated as it contradicted articles 75.2 and 75.3 of the International Code for Zoological Nomenclature (Motomura 2001). Fricke (1999) justified the need of a neotype for the species aiming to stabilize its status and distinguish it unequivocally from S. canicula . However, the author did not review the taxonomy of S. canicula nor provide a diagnosis or any description for it. Here, we provide a diagnosis and redescription of this species and designate a 476 mm TL juvenile male collected in the Mediterranean Sea as the neotype. We believe that this act will reduce misidentifications among specimens of S. stellaris, S. canicula and S. cervigoni .

The geographic distribution of S. stellaris is updated here; specimens from northwestern Africa were reidentified as S. cervigoni . Records for this species are more frequent around the western coast of Italy and in the English Channel.