Scyliorhinus meadi Springer, 1966

Soares, Karla D. A. & De, Marcelo R., 2019, The catshark genus Scyliorhinus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae): taxonomy, morphology and distribution, Zootaxa 4601 (1), pp. 1-147 : 78-87

Scyliorhinus meadi Springer, 1966

( Figs. 56–62 , Tabs. 3 , 13 , 14)

Common names: blotched catshark ( United States), roussette cloquée ( France), alitán pintarrojo ( Spain).

Scyliorhinus meadi Springer, 1966: 600 –601, figs. 7a, 14b (original description, type locality: Florida, United States); Springer, 1979: 139 –141, figs. 90, 91, 92 (taxonomic review); Compagno, 1984: 364 –365, pl. 10 (FAO catalogue); Compagno, 1999: 480 (listed); Compagno et al., 2005: 251, pl. 42 (compilation); Castro, 2011: 340 –341, figs. 88a–e (catalogue, North America); Kyne et al., 2012: 58 (catalogue, southeastern coast of United States); Ebert et al., 2013a: 374, 382, pl. 52 (compilation); Weigman, 2016: 44 (listed).

Scyliorhinus retifer meadi: Springer & Sadowsky, 1970: 92 (taxonomic review); Cadenat & Blache, 1981: 183 -184, fig. 124b (catalogue, Western Africa).

Holotype. USNM 188049 , immature male, 267 mm TL (M/ V Silver Bay station 3711, 28°21’N 79°51’W, 329 m depth off Cape Kennedy , Florida).

Additional material examined. 11 specimens (see Appendix).

Diagnosis. Scyliorhinus meadi differs from all congeners by presenting a color pattern without spots on body (vs. dark spots in S. boa , S. cabofriensis , S. canicula , S. cervigoni , S. duhamelii , S. garmani , S. haeckelii , S. stellaris , and S. ugoi ; light spots in S. capensis , S. comoroensis , S. hesperius , S. torazame , and S. torrei ; reticulated pattern in S. retifer ); saddles prominent and darker than the background (vs. inconspicuous in S. cabofriensis , S. cervigoni , S. duhamelii , S. garmani , and S. torrei ); anterior nasal flaps not reaching the upper lip (vs. flaps reaching the upper lip, and sometimes covering it in S. canicula , S. cervigoni , S. comoroensis , S. duhamelii , S. garmani , and S. stellaris ); counts of monospondylous vertebrae 46–48 (vs. lower values in other species, except in S. capensis , S. garmani and S. stellaris ). The following combination of characters, although less conspicuous, also helps distinguish this species: nasoral grooves absent and anterior nasal flaps situated on the posterior border of excurrent aperture (vs. grooves present and flaps situated laterally in S. canicula and S. duhamelii ); mesonarial ridge not exceeding the posterior border of anterior nasal flaps (vs. exceeding in S. stellaris ); oral canal of lateral line system with 8–10 pores (vs. 5–6 in S. hesperius ; 10–12 in S. duhamelii ; 9–13 in S. torrei ); commissural teeth with one or two cusplets and principal cusp laterally situated (vs. three or more in S. boa , S. canicula and S. hesperius ); interdorsal distance 1.0–1.5 times the anal base length (vs. smaller than the anal base in S. canicula , S. cervigoni , S. comoroensis , S. duhamelii , S. garmani , S. stellaris , and S. torazame ); pelvic apron extending to 2/3 length of pelvic inner margins (vs. extending through almost entire length of inner margins in S. canicula , S. capensis , S. duhamelii , S. torazame , and S. torrei ); clasper with cover rhipidion covered by denticles (vs. not covered in S. boa , S. cervigoni , S. hesperius , and S. retifer ); clasper terminal dermal cover smooth (vs. rough in S. canicula and S. capensis ); neurocranium with width across nasal capsules greater than nasobasal length (vs. smaller in other species); nasal capsule width 1.4 times greater than its length (vs. 0.9–1.2 in the other species); adult male and largest specimen examined 720 mm TL (vs. smaller sizes at sexual maturity in other species, except S. capensis , S. cervigoni and S. stellaris ).

Description. Morphometric and meristic data are given in Table 14, and neurocranial measurements in Table 13 .

Body slender and cylindrical, tapering considerably posterior to cloaca ( Fig. 56 ). Prepectoral length 0.4 times the prepelvic length. Trunk shorter than tail; snout-vent length 0.8 times vent-caudal length. Pectoral-pelvic distance 1.8–2.2 (2.2) times the pelvic-anal space. Interdorsal distance 1.4–2.2 (2.1) times the dorsal-caudal space ( Tab. 14). No interdorsal, postdorsal or postanal ridges; lateral crest on caudal peduncle absent.

Head moderately broad and depressed; head length 1.4–1.5 (1.4) times head width ( Figs. 56 , 57 ). Snout relatively short, preoral length 0.5–0.6 (0.5) times mouth width and 1.5–1.7 (1.4) times smaller than preorbital length. Prenasal length 0.7–0.8 (0.5) times internarial space; preorbital length 1–1.1 (0.8) times interorbital space.

Eye large and slitlike, eye length 2.3–2.4 (2.1) times its height and 0.2 times smaller than head length ( Fig. 56 ). 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 4.3–6.2 (4.7) times in eye length and 9–13 (11.1) times in interorbital width.

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 extending just anterior to mouth, close to the upper lip but not touching it ( Figs. 58 A–B). Mesonarial ridge distinct but not exceeding 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 triangular and corresponding to 1/4 of anterior nasal flap. Internarial space 1.1–1.3 (1.4) times smaller than interorbital space.

Mouth arched, longer than wide, its length goes 1.6–1.9 (1.5) times in mouth width ( Figs. 58 A–B). Lower labial furrow short and narrow, 3.1–3.8 (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. 59 ). Sexual heterodonty not observed; only females examined. Tooth counts 23–26 23–26/ 21–24 1 21 –25 (27–27/24–25). Parasymphysial teeth with a principal cusp flanked by one cusplet on each side; cusplets 1/3 the height and half the width of the principal cusp. Protuberances on medial portion of the crown base and striae running from the crown base toward the apex of the principal cusp. Anterior teeth larger than the parasymphysial and principal cusp less stout. Anterior teeth with four cusplets; marginal cusplets poorly developed. Anterior lower teeth with marginal cusplets more developed and corresponding to half the height of principal cusp. Protuberances on the crown base and striae throughout the crown, more prominent in upper teeth. Lateral teeth with three cusplets; two cusplets at the mesial edge and one at the distal edge. Mesial proximal and distal cusplets corresponding to half the height of principal cusp and mesial marginal poorly developed. Principal cusp slightly oblique in both jaws. Protuberances on the crown base and striae throughout the crown. Commissural teeth with one or two cusplets; principal cusp stronger, slightly oblique and laterally situated. Cusplets corresponding to half or 2/3 the width and the height of the principal cusp. Protuberances present 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- or trident-shaped crowns, 1.4–2.1 times as long as wide ( Tab. 3 ); anterior part covered with ectodermal pits. Dermal denticles above the pectoral fin trident-shaped, with no median ridge and presenting one lateral ridge on each side. Denticles below the dorsal fins teardrop-shaped, with prominent medial ridge running throughout the principal cusp. Cusplets poorly developed, 0.3 times the principal cusp; lateral ridges reduced or absent. Males presenting larger denticles than females ( Fig. 60 ).

Pectoral base 0.7–1.1 (0.8) times mouth width. Pectoral anterior margin 1.4–1.9 (2.1) times its base and 1.4–1.9 (1.9) times the posterior margin. Pectoral fin skeleton aplesodic with radials mostly divided into three segments. Propterygium and mesopterygium trapezoids; the former smaller than the latter. Propterygium with one proximal segment; mesopterygium with 3–4 proximal segments fused proximally. Metapterygium with 9 segments. Metapterygial axis rectangular and corresponding to 1/5 of metapterygium.

Pelvic fin triangular ( Fig. 58F ); pelvic anterior margin 1–1.2 (1.1) times the posterior margins and 0.8–1 (1.1) times the pelvic base. Pelvic inner margins of males fused for 2/3 of their extension; claspers of juveniles evident without lifting the pelvic apron.

Clasper short and cylindrical ( Fig. 58F ), sometimes extending beyond free rear tips of pelvic fins; clasper inner length 0.6–0.9 (0.5) times the pelvic anterior margin, 1.6–2.4 (2.3) times the clasper outer length and 5.2 (5.0) times the clasper base. Most of clasper surface except dorsomedial surface of glans, envelope, medial border of cover rhipidion, rhipidion, and terminal dermal cover, covered by dermal denticles with anteriorly directed crowns ( Fig. 61 ). Clasper hooks absent. Rhipidion poorly developed, not expanded distally and 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 poorly developed, visible only internally. Terminal dermal cover extending for 1/3 of the clasper glans and covering the posterior tips of exorhipidion and cover rhipidion. Clasper skeleton not examined.

First dorsal fin triangular, never square-tipped, with nearly straight anterior margin, rounded apex and angular free rear tip ( Fig. 56 ). First dorsal fin origin opposite to the pelvic fin insertion. First dorsal fin insertion opposite to the anterior 2/5 of pelvic-anal distance. Anterior margin 1.5 times first dorsal fin base; first dorsal fin height 0.7–0.8 (0.8) times its base.

Second dorsal fin smaller than the first and triangular, sometimes subrectangular ( Fig. 56 ). Second dorsal fin origin opposite to half-length of anal base and to the posterior end of anal fin. Anterior margin 1.3–1.4 (1.4) times base of second dorsal fin; second dorsal base 1.6–1.9 (1.4) times its height and 0.9–1.7 (1.34) times the dorsalcaudal distance. First dorsal fin 1.4 (1.2) times larger than the second dorsal fin.

Anal fin triangular, apically narrow, not falcate and similar to second dorsal fin ( Fig. 56 ); anal fin base 1.5–1.6 (1.5) times the second dorsal fin base. Anal fin anterior margin nearly straight, apex narrowly rounded, free rear tip acutely pointed, and inner margin straight. Anal fin base 0.9–1.0 (0.9) times the interdorsal distance and 1.4–2.6 (1.9) times the dorsal-caudal distance. Anal anterior margin 1.7–2.3 (2.2) times the posterior margin; anal fin height 0.4 times its base.

Caudal fin narrow-lobed and asymmetrical ( Fig. 56 ). Dorsal caudal lobe 2–2.5 (2.0) times greater than preventral lobe; subterminal caudal margin 0.9–1.5 (1.0) times the terminal margin. Caudal crest of enlarged denticles absent on caudal fin margins.

Neurocranium broad and somewhat flattened, corresponding to 9.6% TL; only one specimen dissected. Rostrum length 1.1 times the distance between lateral rostral cartilages. Nasal capsule wider than long, oval-shaped and expanded laterally; width 1.4 times its length. Orbital region 2.2 times smaller than nasobasal length. Otic capsule short, its length 4.6 times smaller than nasobasal length and width 2.7 times otic capsule length. Width across postorbital processes similar to the preorbital processes width ( Tab. 13 ).

Coloration in alcohol. Body beige with seven eight saddles darker than the background color, interspaced by subsaddles on sides and forming a ‘chessboard’ pattern; interdorsal and precaudal saddles inconspicuous or absent ( Figs. 56 , 57 ). Subsaddles present to the first dorsal fin. Branchial region darker than the background color. Light or dark spots absent; when spots present always lighter than the background, smaller than spiracles and located within saddles. Belly and ventral surface of paired fins without spots, cream in color.

Distribution. This species is known to occur from the southeastern coast of United States, between Florida and the Bahamas (24°N, 79°W), north to Cape Fear, southern South Carolina (34°N, 75°W) ( Fig. 62 ).

Biological data. Immature specimens measure between 180–490 mm TL; adult male and largest specimen examined 720 mm TL and largest female 419 mm TL. Certainly oviparous, but nothing is known about reproduction. Diet consists of cephalopods, euphausiids, shrimps and bony fishes ( Burgess et al. 1979; Parsons 1985). This species is a benthic dweller in depths of 146– 548 m. Conservation status ‘Data Deficient’ ( Sherrill-Mix & Burgess 2006).

Etymology. The specific name ‘meadi’ was dedicated to Giles W. Mead, who first mentioned to Stewart Springer the distinctiveness of this species.

Remarks. Scyliorhinus meadi was described by Springer (1966) and distinguished from S. hesperius on the basis of the differences in color pattern. Posteriorly, S. meadi was considered a subspecies of S. retifer by Springer & Sadowsky (1970), although, some doubt persisted about its validity because only six juveniles and post juvenile specimens (183 to 270 mm long) were known. Springer (1979) erected it to species rank, but no further explanations were given, and mature specimens were not examined. However, a 490 mm TL specimen from Cape Fear and with small claspers was examined which increased the knowledge of this species, which was then considered the larger catshark species of the Western Central Atlantic. In this study, a 720 mm TL mature male (UF 166596) with well-developed claspers was examined, adding to our knowledge about the external morphology of claspers and size at maturity.

The record of this species in Mexican waters by Espinoza Pérez & Huidobro Campos (1995) is a misidentification. In the brief account and illustration provided by the authors (p. 2, fig. 1), we noted that the specimen belongs to the genus Galeus (freckled color pattern and dorsal fins similar in size). Besides these features, maturity sizes given by the authors (247–322 mm TL) contradict other specimens of S. meadi ( Springer 1979; present study). The two other occurrence records for this species, from the western Dry Tortugas (83.5°W; Kiraly et al. 2003) and northern Jamaica ( McLaughlin & Morrissey 2004), are not considered here to be S. meadi . The first one corresponds to a misidentification of S. retifer , whereas the second is, probably, a specimen of Cephaloscyllium . The specimen illustrated by McLaughlin & Morrissey (2004) presents ten saddles darker than the background (vs. eight saddles in S. meadi ), and the first dorsal fin is opposite to the half-length of the pelvic base (vs. dorsal fin posteriorly situated in S. meadi ).

Figures

FIGURE 56. Holotype of Scyliorhinus meadi Springer, 1966, USNM 188049, male, 267 mm TL (Florida, United States, 28°21’N 79°51’W). A, dorsal view; B, lateral view. Scale bar = 20 mm.

FIGURE 57. Scyliorhinus meadi; dorsal view. A, MCZ 42986, female, 185 mm TL (Florida, United States, 28°21’N, 79°51’W); B, UF 107118, female, 252 mm TL (Florida, United States, 28°36’N, 79°51’W); C, USNM 188051, male, 190 mm TL (Florida, United States, 29°44’N, 80°12’W). Scale bar = 20 mm.

FIGURE 58. Scyliorhinus meadi. A, UF 29835, female, 390 mm TL (North Carolina, United States, 34°12.7’N, 75°51.5’W); B, UF 42186, female, 419 mm TL (Florida, United States, 28°59.51’N, 79°55.29’W); C–E, USNM 188051, male, 190 mm TL (Florida, United States, 29°44’N, 80°12’W); F, UF 166596, male, 720 mm TL (North Carolina, United States). A, B, ventral view of head; C, detail of pectoral fins; D, lateral view of head; E, dorsal view of head; F, detail of pelvic fins and claspers. Scale bar = 20 mm.

FIGURE 59. Teeth of Scyliorhinus meadi; labial view, USNM 221594, male, 271 mm TL (Bahamas, 24°48’N, 79°17’W). a, anterior tooth; c, commissural; l, lateral. Scale bar = 100 µm.

FIGURE 60. Dermal denticles of Scyliorhinus meadi. A–B, UF 29835, female, 390 mm TL (North Carolina, United States, 34°12.7’N, 75°51.5’W); D–F, USNM 221594, male, 271 mm TL (Bahamas, 24°48’N, 79°17’W). A, D, region above pectoral fin base; B, E, region below first dorsal fin origin; C, F, region below second dorsal fin insertion. Scale bar = 250 µm.

FIGURE 61. Clasper of Scyliorhinus meadi; dorsal view, UF 166596, 720 mm TL (North Carolina, United States). ap, apopyle; crh, cover rhipidion; erh, exorhipidion; hp, hipopyle; rh, rhipidion; tdc, terminal dermal cover. Scale bar = 20 mm.

FIGURE 62. Map showing the geographic distribution of Scyliorhinus meadi based on material examined in this study. Black star indicates the type locality.

Tables

TABLE 14. Morphometric and meristic data of Scyliorhinus meadi. SD, standard deviation; n, number of examined specimens. Total length (TL) in mm, other measurements as percentages of TL.

Characters	Holotype	n	Range	Mean	SD
Total length (TL)	266.9	13	174.7—720.0	290.9	109.4
Precaudal length	74.2	13	70.6–75.0	72.6	1.6
Eye-spiracle length	0.9	13	0.8–1.4	1.1	0.2
Prenasal length	3.2	13	2.5–4.5	3.4	0.6
Preoral length	4.9	13	4.3–5.9	5.1	0.4
Preorbital length	6.7	13	6.7–9.8	7.6	0.9
Prespiracular length	10.0	13	10.0–12.8	11.5	0.9
Prebranchial length	13.	13	13.8–17.4	16.3	1.1
Head length	17.6	13	17.6–22.1	20.4	1.2
Prepectoral length	15.6	13	15.6–20.8	18.7	1.2
Prepelvic length	37.2	13	37.2–46.1	40.8	2.4
Snout-vent length	40.4	13	40.4–50.6	43.9	2.9
Vent-caudal length	50.6	13	47.8–59.5	55.2	3.2
Pre-first dorsal length	42.8	13	42.8–51.1	46.4	2.1
Interdorsal distance	8.9	13	8.9–11.9	10.4	0.9
Dorsal-caudal distance	4.3	13	3.2–8.5	5.1	1.3
Pectoral-pelvic distance	17.4	13	14.2–23.9	18.0	2.8
Pelvic-anal distance	7.9	13	7.9–10.9	9.3	1.0
Anal-caudal distance	4.7	13	4.7–8.1	8.2	0.7
Interorbital distance	7.8	13	6.5–9.0	6.2	0.4
Internarial distance	5.8	13	5.8–7.1	5.5	0.5
Mouth length	4.3	13	4.3–6.2	9.2	0.6
Mouth width	8.7	13	8.3–10.1	2.7	0.3
Lower labial furrow length	2.2	13	2.2–3.2	3.7	0.4
Eye length	3.3	13	3.1–4.3	1.6	0.2
Eye height	1.6	13	1.3–1.9	0.8	0.2
Spiracle length	0.7	13	0.5–1.0	2.6	0.3
First gill slit height	2.7	13	2.1–2.9	1.4	0.2
Fifth gill slit height	1.5	13	0.9–1.8	12.7	1.0
Pectoral length	12.1	13	10.4–13.9	14.0	1.0
Pectoral anterior margin	14.1	11	12.1–15.7	6.9	1.4
Pectoral base	6.7	13	6.2–11.1	8.3	1.5
Pectoral posterior margin	7.4	13	6.2–11.3	5.6	0.8
Pectoral inner margin	6.1	13	4.5–7.0	6.6	0.7
Pelvic length	10.0	13	8.3–12.1	6.2	1.1
Pelvic anterior margin	6.3	13	5.2–7.6	7.5	1.2
Pelvic posterior margin	5.8	13	4.3–7.9	3.5	0.9
Pelvic base	5.9	13	5.3–9.9	1.9	1.1
Pelvic inner length	4.0	13	2.6–5.7	4.2	1.4
Clasper outer length	1.5	7	1.3–4.4	0.8	0.3
Clasper inner length	3.5	7	3.1–7.2	9.0	0.6

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