Scyliorhinus ugoi, Soares, Karla D. A., Gadig, Otto F. B. & Gomes, Ulisses L., 2015

Soares, Karla D. A., Gadig, Otto F. B. & Gomes, Ulisses L., 2015, Scyliorhinus ugoi, a new species of catshark from Brazil (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), Zootaxa 3937 (2), pp. 347-361 : 348-359

Scyliorhinus ugoi sp. nov.

( Figs. 1–9 )

Proposed common name: dark freckled catshark (English), cação-gato negrinho (Portuguese). Scyliohinus sp.: Gadig, 2001, pp. 149–150, coast of Espírito Santo state; Gomes et al. 2010, pp. 85–86, fig. 110, coast of Rio de Janeiro state.

Scyliorhinus hesperius: Gadig & Gomes, 2003 , p. 22, coasts of Espírito Santo and Rio de Janeiro states. Scyliorhinus sp. 1: Soares, 2014, pp. 80–84, figs. 17, 68.

Holotype. MNRJ 42619, adult female, 496 mm TL (southern Bahia, Central Brazilian coast).

Paratypes. MZUSP 110448, adult male, 465 mm TL (Alagoas, Northeastern Brazil, 9° S 34° 50’W); MZUSP 110449, adult male, 445 mm TL (Rio Grande do Norte, Northeastern Brazil, 6° 14’S 34° 51’W); UERJ 1725, adult male, 530 mm TL (Central Brazilian coast, between southern Bahia and northern Rio de Janeiro; cranium, jaws and claspers); UERJ 2179, immature male, 415 mm TL (southern Bahia, Central Brazilian coast).

Additional material examined. 5 specimens (see Appendix).

Diagnosis. A southwestern Atlantic Ocean Scyliorhinus distinguished by a considerably broad head (vs. slender in the S. haeckelii / besnardi group and S. hesperius ), and color pattern with brown saddles on a light brown background, predorsal saddles with anterior and posterior sharp median projections (vs. no projections in the S. haeckelii / besnardi group or S. hesperius ); and light and dark, spiracle-sized or slightly smaller spots, lacking large white spots (vs. large white spots in S. hesperius ). The following combination of characters also distinguishes these species: snout rounded and moderately short, preoral length 5% TL (vs. 4.5% TL in the S. haeckelii / besnardi group); preorbital length 6.4% TL and head length 20% TL (vs. 5% TL and 18% TL in S. hesperius ); mouth width corresponding to 9% TL (vs. 8% TL in the S. haeckelii / besnardi group and 7.2% TL in S. hesperius ); pectoral-pelvic space 1.5 times pelvic-anal space (vs. equal in the S. haeckelii / besnardi group), and interdorsal space 2.3 times dorsal-caudal space (vs. 1.6 times in S. haeckelii / besnardi group); anal-fin base 8% TL (vs. 6.7% TL in S. hesperius and 8.3% TL in the S. haeckelii / besnardi group); cranium with flat basal plate, without keels; cranial width larger in females (42.7% NL) (vs. 37.4% NL in the S. haeckelii / besnardi group); a terminal dermal cover present in hindmost portion of clasper, covering terminal cartilages (lacking in S. hesperius ); medium-sized, adult male at 445 mm TL and adult female 500 mm TL (vs. 353 mm and 410 mm, respectively, for the S. haeckelii / besnardi group).

Description. Morphometric measurements are given in Table 1 and cranial measurements in Table 2 . Modes of meristic counts are given as well their range in parentheses (if different).

Head ( Fig. 2 a–c) broad and depressed, greatest width 0.63 times of head length. Snout thick, somewhat flattened and relatively short, preoral length corresponding to 4.3–5.6% TL and 0.5 times the mouth width. Ampullae pores not greatly enlarged on snout. Preoral length 1.1–1.4 times in preorbital length (vs. 1.4–1.7 in the Scyliorhinus haeckelii / besnardi group) ( Tab. 1 ).

Measurements Scyliorhinus ugoi sp. nov. Scyliorhinus haeckelii / besnardi ......continued on the next page Measurements Scyliorhinus ugoi sp. nov. Scyliorhinus haeckelii / besnardi Eyes ( Fig. 3 ) large and spindle-shaped; eye length 5.2 times in head length and 2.5–4.2 times eye height. Eyes dorsolateral on head, with lower edges well medial to horizontal head rim in dorsal view; subocular ridges strong. Nictitating lower eyelids of rudimentary type (sensu Compagno, 1970), with shallow subocular pouches and secondary lower eyelids free from upper eyelids. Prespiracular length corresponding to 10.5% TL ( Tab. 1 ). Nostrils ( Fig. 4 ) with broad incurrent apertures, without nasoral grooves or nasal barbels, small oval excurrent apertures and short posterior nasal flaps. Anterior nasal flaps large, covering posterior nasal flaps and excurrent apertures somewhat anterior to mouth. Internarial space 2.4–4.6 times in interorbital space.Mouth ( Fig. 4 ) broadly arched, moderately wide and short, mouth width 2.2 times in head length; mouth length 0.5 times in mouth width. Teeth prominently exposed in ventral view. Lower labial furrows short, 0.2 times in mouth width; upper labial furrows absent. Tongue moderate-sized flat and rounded, occupying most of mouth floor. Dorsal labial cartilages 1.5 times the ventral one; anterior tip of dorsal cartilages reaching orbital processes of palatoquadrate.

First two gill openings about equally long; first gill opening twice as large as fifth ( Fig. 2 c). All gill openings slightly concave and not elevated on dorsolateral surface of head, gill filaments not visible externally.

Sexual heterodonty weak; adult males presenting teeth longer with undeveloped lateral cusps on central portion of lower jaw. Upper teeth slightly higher-crowned than lower teeth, with longer, stronger transverse ridges, otherwise very similar. Medial teeth (M) and anteroposterior teeth (AN) poorly differentiated; symphysial teeth (S) with higher-crown and smaller than anteroposteriors, with erect or semi-erect cusps and one weak cusplet on either side of the cusp. Anteroposteriors in both jaws larger than medials and symphysials, with semi oblique cusps, usually one strong high cusplet on either side, longitudinal ridges confined to the basal ledges, and low, flat roots. Gradient monognathic heterodonty well-developed in anteroposterior teeth; anteroposteriors smaller distally, with thicker and more oblique cusps, and lower cusplets.

Teeth in 52/49 (47–56/45–53) rows, 3/2 (2–3/2–3) functional series. Teeth not highly differentiated in upper and lower jaws or along jaws. Tooth formula:

Left AN16–19 M6–8 S1 S1 M6–8 AN16–19 Right

AN15–17 M6–9 M7–10 AN16–17

Lateral trunk denticles ( Fig. 5 ) with flat, elongated teardrop-shaped crowns 1.4–2.1 times as long as wide, anterior part covered with ectodermal pits (sensu Muñoz- Chápuli, 1985). Crown with a strong medial ridge that extends entire length of crown on the long medial cusp. Lateral cusps not well developed, 0.3 times in medial cusp; lateral ridges anterior to them very short or absent. Males with dermal denticles longer than females. Density of dermal denticles on posterior regions lower than on anterior regions.

Measurements Scyliorhinus ugoi sp. nov.

F % NL M % NL Distance between rostral base and anterior edge of anterior 21 39.5 19.5 36.7–38.8 fontanelle

Body ( Fig. 1 ) stout and depressed on head region, tapering considerably to caudal fin. Prepectoral length corresponding to 17.9% of total length (TL) and prepelvic length 41– 43.4% TL. Snout– vent length 0.8 times in vent-caudal length. Pectoral-pelvic space 1.5–1.6 times pelvic–anal space (vs. 0.8–1.4 in the Scyliorhinus haeckelii / besnardi group). Interdorsal space 2.1–2.5 times dorsal-caudal space ( Tab. 1 ).

Pectoral fins ( Figs. 1 and 2 ) large and rounded-triangular, not falcate, with narrowly rounded apexes and broad bases. Origin of pectorals under interspace between third and fourth gill openings. Pectoral base 0.3– 0.7 times mouth width (vs. 0.8 times in the Scyliorhinus haeckelii / besnardi group). Pectoral anterior margin 2–4.8 times its base (vs. 1.7– 2.3 in the Scyliorhinus haeckelii / besnardi group) and 1.6 times the posterior margin ( Tab. 1 ).

Pectoral fin skeleton aplesodic ( Fig. 6 ) with radials mostly divided into three segments, longest distal radial segment (DRA) 1.8 times length of its proximal radial segment (PRA). Pectoral skeleton tribasal, propterygium ( PRO) with a single radial, mesopterygium (MES) with 3 radials, and metapterygium (MET) with 8 (7–9) radials on basal segment and 1 (1–2) on metapterygial axis (MTS); total radial count 13 (12–15). Propterygium small, short and rectangular or trapezoidal. Mesopterygium short, diamond-shaped and slightly elongated and distally expanded in the axes of its radials. A fused plate formed by the proximal segment of the second, third and fourth mesopterygial radials. Metapterygium basal segment triangular, elongated slightly diagonal to the axes of its radials; metapterygial axis quadrangular, trisegmental, and with length about 0.4 times of metapterygial basal segment. This segment presents a projection directed anteriorly in its inner margin.

Pelvic fins ( Fig. 2 ) broadly triangular; pelvic anterior margins 0.5 times of pectoral anterior margins. Pelvic anterior margin 0.9–1.1 times posterior margin ( Tab.1 ). Total radial count 13 (12–15).

Claspers ( Fig. 7 ) moderately long and slender, cylindrical and blunt-tipped, extending free rear tips of pelvic fins, by a distance about 0.2 times pelvic inner margin. Most of clasper except dorsomedial and posteromedial surface of glans (including rhipidion) covered by large denticles with anteriorly directed cusps. An envelope (EN) delimits anteriorly an exorhipidion (ERH) not differentiated from lateral edge of glans, specialized clasper hooks absent. Rhipidion (RH) well developed medially covered by a poorly developed cover rhipidion (CRH).

Pseudosiphon poorly developed and visualized only internally; pseudopera absent. Apopyle (AP) and hypopyle (HP) connected by a long clasper groove, with its dorsal margins fused over the clasper groove. Clasper skeleton ( Fig. 7 b) relatively simple. The axial cartilage connected proximally by a single basal segment and a dorsal beta cartilage to the pelvic basipterygium. Clasper shaft slender and formed from the axial cartilage and tightly rolled dorsal and ventral marginal (RD and RV) cartilages. A poorly developed acessory dorsal marginal cartilage (RD2) present between the terminal portion of the dorsal marginal cartilage and anterior portion of the dorsal terminal (TD); this cartilage supports the rhipidion. The skeleton of the clasper glans comprises a large, curved, wedge-shaped dorsal terminal and a similarly shaped ventral terminal (TV), articulating with and separated by a terminal extension of the axial cartilage, the narrow end-style (G); ventral terminal longer than dorsal terminal cartilage. There is no accessory terminal cartilage or dorsal terminal 2 cartilage, but a slender ventral terminal cartilage (TV2) is positioned on the ventral terminal cartilage. A terminal dermal cover (TDC – new term) present in the hindmost portion of the clasper, covering the terminal cartilages and presenting no denticles.

First dorsal fin ( Figs. 1 , 2 ) triangular, apically narrow and not falcate, with nearly straight anterior margin, rounded apex and angular free rear tip. First dorsal origin above to insertions of pelvic fins. First dorsal base 1.6 times in interdorsal space, 3.4 times in dorsal caudal margin. First dorsal anterior margin 1.4 times its base; first dorsal height 0.8 times first dorsal base. Total radial count 13 (12–14).

Second dorsal fin ( Figs. 1 , 2 ) low, triangular, apically narrow and not falcate; second dorsal fin height 0.7 times first dorsal fin height, base 0.8 times first dorsal fin base. Second dorsal fin with nearly straight anterior margin, bluntly rounded apex, narrowly rounded free rear tip, and straight inner margin. Second dorsal fin origin slightly behind anal midbase. Second dorsal fin base 0.7 times in dorsocaudal space, second dorsal fin height 1.4 times in second dorsal fin base. Total radial count 10 (9–12).

Anal fin low ( Figs. 1 , 2 ), apically narrow, not falcate and somewhat larger than second dorsal fin, anal fin height 1.1 times second dorsal fin height and base 1.3 times 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 without preanal ridges, anal fin origin and anal fin base length behind pelvic fins insertions. Anal fin base 0.5 times interdorsal space (vs. 0.6–0.8 in the Scyliorhinus haeckelii / besnardi group) and 1.3–1.5 times dorsocaudal space. Anal anterior margin 1.5–1.7 times posterior one, anal fin height 1.8 times in anal fin base. Total radial count 20 (18–22).

Caudal fin ( Figs. 1 , 2 ) narrow-lobed and asymmetrical, with large and hardly developed terminal lobe. Caudal fin short, dorsal margin 3.2 times in precaudal length; subterminal margin 0.9–1 time in terminal margin. Dorsal caudal fin margin slightly convex, without lateral undulations. No crests of denticles on the caudal fin margins.

Total vertebral counts 127 (119–135), monospondylous precaudal centra (MP) 39 (38–39). Transition between monospondylous and diplospondylous (DP) centra behind pelvic fin bases and over clasper shafts. Last MP centra before MP–DP transition smaller than the anterior and larger than the first DP, not forming a 'stutter- zone' of alternating long and short centra.

Intestinal valve of conicospiral type, with 6 (6–8) turns.

Cranium ( Fig. 8 ) broad and flattened, corresponding to 10% TL ( Tab. 2 ). Rostral cartilages short and slender; rostrum length 20.8–29.3% of nasobasal length (NL). Medial rostral cartilage (MR) originates from anteroventral tip of internasal septum and extends anterodorsally. Distance between lateral rostral cartilages (LR) proportionately larger on females (13.8–14.5% NL) than males (12.2–13% NL). Nasal capsules (NC) large, transversely oval, its width larger than length. Width across capsules 76– 85.4% NL. Nasal apertures (NA) broadly circular and laterally positioned on capsules; two thirds of its area covered by nasal fontanelle (NF). Males with nasal apertures proportionately larger (26.5– 27.7% NL) than females (25– 25.8% NL). Internasal septum (IS) high and compressed, not hypercalcified in adults. Distance between rostral base and anterior edge of anterior fontanelle (AF) proportionately larger in females (39.5% NL) than males (36.7– 38.8% NL). Cranial roof (CRF) broadly arched between supraorbital crests (SC) in frontal view, with a definite saddle-like medial depression in lateral view. Anterior fontanelle broad and subquadrate on males and heart-shaped on females, length 1.3 times width, width 4 times in nasobasal length. Basal plate flat, without keels; width larger in females (39.6–45.8% NL) (vs. 33.3–40.8% NL in the Scyliorhinus haeckelii / besnardi group). Orbits oval-subquadrate in shape; its length 2.2 times in nasobasal length. Supraorbital crests low, strong and deeply arched. Postorbital processes (PTP) angular, situated on anterior ends of optic capsules; width across postorbital processes 1.2 times preorbital processes (PEP). Optic capsules short, length 4.7 times in nasobasal length; its width 2.5–2.7 times optic capsules length. Hyomandibular facets (HF) large, extending across the entire lateral face of each optic capsule, with slightly exserted ends.

Color pattern with brown saddles on a light brown background, predorsal saddles with anterior and posterior sharp median projections; light and dark spots spiracle-sized or slightly smaller, no large white spots. Light brown on ventral region; some specimens with dark points on body and fins. Remarkably darker than the Scyliorhinus haeckelii / besnardi group and S. hesperius .

Distribution and biological data. This species ( Fig. 9 ) is recorded from the coast of the states of Rio Grande do Norte, Pernambuco, Alagoas, Bahia (northeastern Brazil), Espírito Santo, and northern Rio de Janeiro (southeastern Brazil). Accurate occurrence records are known only for a few specimens, but this species has been collected for several years between Rio Grande do Norte and Rio de Janeiro states. Most specimens recorded are demersal, about 400–500 m deep, associated with coral formations, where it possibly lays its egg-cases. Stomach contents include small invertebrates (cephalopods), small bony fishes, and one hagfish (Class Myxini) egg-case was found in the stomach of an adult specimen. Maximum total length about 630 mm. Size of the first maturity not well defined, but 450 mm TL males and 470 mm TL females are adults. Males ranging in size from 419–534 mm and females from 431–630 mm. Reproduction is by oviparity, producing at least two amber colored egg capsules, one for each uterus, which are smooth, lacking longitudinal grooves and measuring about 152 mm long and 58 mm wide ( Gadig, 2001; Gomes et al, 2010).

Etymology. The specific name ugoi is dedicated to Ugo de Luna Gomes, son of Ulisses L. Gomes.

Comparisons with other species of Scyliorhinus . Seven species of Scyliorhinus are readily distinguished from Scyliorhinus ugoi by color pattern. Scyliorhinus retifer ( Garman, 1881) has a unique reticulated pattern of dark lines; S. boa Goode & Bean, 1896 , S. canicula Linnaeus, 1758 , S. cervigoni Maurin & Bonnet, 1970 , S. garmani (Fowler, 1934) , and S. stellaris Linnaeus, 1758 have conspicuous, small to medium-sized, rounded dark spots and indistinct saddle blotches ( Springer, 1979; Compagno, 1984; Compagno et al., 2005). In the Scyliorhinus haeckelii / besnardi group, when contrasting saddles are present, specimens lack pre-dorsal saddles with anterior and posterior sharp median projections ( Soares, 2014). Scyliorhinus meadi Springer, 1966 has a color pattern of dark saddles on a light background, without light or dark spots ( Springer, 1979; Compagno, 1984).

Scyliorhinus ugoi , S comoroensis Compagno, 1988 , S. capensis (Müller & Henle, 1838) , S. torrei Howell- Rivero, 1936, S. hesperius Springer, 1966 , S. tokubee Shirai, Hagiwara & Nakaya, 1992 , and S. torazame (Tanaka, 1908) are similar in having a color pattern of light spots on a darker background, combined with dark saddles, but only Scyliorhinus ugoi presents small dark spots and pre-dorsal saddles with anterior and posterior sharp median projections ( Springer, 1979; Compagno, 1988; Shirai et al., 1992; Compagno et al., 2005; Soares, 2014).

Scyliorhinus canicula has relatively larger, broader anterior nasal flaps that reach the mouth, covering the shallow nasoral grooves that are lacking in S. ugoi and in all other species of the genus ( Springer, 1979; Compagno, 1984; Compagno et al., 2005; Soares, 2014).

Scyliorhinus haeckelii / besnardi from the Southwestern Atlantic Ocean differs from S. ugoi in its smaller size, with adult males known at about 350–370 mm, while in S. ugoi males at about 420 mm are still immature. Its snout is more slender, usually more pointed and longer than that of S. ugoi , with preoral length 1.4–1.7 times in preorbital length vs. 1.1– 1. 4 times in S. ugoi ( Soares, 2014) . The wider and stout head of S. ugoi is easily observable in all specimens and, together with its characteristic color pattern, permits a precise distinction.

The abdomen of S. ugoi is relatively longer than in S. haeckelii / besnardi , with pectoral–pelvic space 1.5–1.6 times pelvic–anal space vs 0.8–1.4. Interdorsal space 2.1–2.5 times dorsal–caudal space vs. 1.2–2 in the Scyliorhinus haeckelii / besnardi group ( Soares, 2014).

Monospondylous vertebral counts of S. ugoi (38–39) differ from counts for S. meadi (43–49), S. torrei (30–34), S. comoroensis (45) and S. capensis (48), but do not differ appreciably from counts for S. retifer , S. boa , S. hesperius and S. haeckelii / besnardi (Springer & Sadowsky, 1970; Springer, 1979; Compagno, 1988b; Soares, 2014).

The occurrence of S. hesperius in the uppermost slope (274–457 m in depth) of the Atlantic from Central America to Brazil ( Gadig & Gomes, 2003) is an error of identification and refers, in fact, to S. ugoi ( Soares, 2014) . Beyond the differences in color pattern, S. ugoi has a larger head, with preorbital length 6.4% TL and head length 19.5–20.3% TL vs. 4.9–5.3% TL and 18.9% TL in S. hesperius , respectively. The mouth is also larger in S. ugoi , its width 9.0–9.7% TL vs. 7.0– 7.5 in S. hesperius , as is its anal base length at 7.7–8.2% TL vs. 5.7–7.7% TL in S. hesperius ( Springer, 1979; Soares, 2014).

It is apparent from the comparisons presented above that S. ugoi is not particularly close to its geographically nearest congener, S. haeckelii / besnardi of the southwestern Atlantic Ocean, and is differentiated from S. hesperius of Central America by color pattern and body proportions.

Figures

FIGURE 1. Scyliorhinus ugoi sp. nov., holotype, MNRJ 42619, female, 500 mm TL. A) Dorsal view. B) Lateral view; paratype, UERJ 2179, male, 419 mm TL. C) Dorsal view. D) Lateral view. Scale bar: 5 cm.

FIGURE 2. Scyliorhinus ugoi sp. nov. A) Dorsal view of the head of a female, MNRJ 42619, female, 500 mm TL. B) Dorsal view of the head of a male, UERJ 2179, 419 mm TL. C) Lateral view of head, UERJ 2179 male, 419 mm TL. D) First dorsal fin. E) Second dorsal fin. F) Anal fin. G) Caudal fin. H) Ventral view of trunk, MNRJ 42619, female, 500 mm TL. Scale bars: 2 cm.

FIGURE 3. Eye of Scyliorhinus ugoi sp. nov., MNRJ 42619, female, 500 mm TL. Scale bar: 2 cm.

FIGURE 4. Nostrils and mouth of Scyliorhinus ugoi sp. nov., MNRJ 42619, female, 500 mm TL. Scale bar: 2 cm.

FIGURE 5. Lateral trunk denticles of Scyliorhinus ugoi sp. nov. A – C) UERJ 1726, female, 602 mm TL. D – F) UERJ 1725, adult male, 534 mm TL. A, D) Region above pectoral fin. B, E) Region below first dorsal fin. C, F) Region below second dorsal fin.

FIGURE 6. Pectoral fin skeleton of Scyliorhinus ugoi sp. nov., UERJ 1722, female, 600 mm TL. Scale bar: 2 cm. DRA, distal segment; MES, mesopterygium; MET, metapterygium; MTS, metapterygial axis; PRA, proximal segment; PRO, propterygium.

FIGURE 7. Clasper of Scyliorhinus ugoi sp. nov., UERJ 1725, male, 530 mm TL. A) Clasper gland. B) Skeleton. Scale bar = 5 mm. AP, apopyle; CRH, cover rhipidion; G, end-style; EN, envelope; ERH, exorhipidion; HP, hypopyle; RD, marginal dorsal cartilage; RD 2, accessory marginal dorsal cartilage; RH, rhipidion; RV, marginal ventral cartilage; TD, terminal dorsal cartilage; TDC, terminal dermal cover; TV, terminal ventral cartilage; TV 2, terminal ventral cartilage 2.

FIGURE 8. Cranium of Scyliorhinus ugoi sp. nov., UERJ 1725, male, 530 mm TL. A) Dorsal view. B) Ventral view; UERJ 1726, female, 597 mm TL. C) Dorsal view. D) Ventral view. Scale bar = 1 cm. AF, anterior fontanelle; ASC, anterior semicircular canal; CRF, cranial roof; FOE, external foramen of preorbital canal; FPE, external profundus foramen; HF, hyomandibular facet; ICF, internal carotid foramen; IS, internasal septum; LR, lateral rostral cartilage; MR, medial rostral cartilage; NA, nasal aperture; NC, nasal capsule; NF, nasal fontanelle; OC, optic capsule; PEP, preorbital process; PRF, parietal fossa; PSC, posterior semicircular canal; PT, pterotic process; PTP, postorbital process; SC, supraorbital crest; SF, stapedial foramen; SG, supraorbital groove; SS, suborbital shelf.

FIGURE 9. Distribution of Scyliorhinus ugoi sp. nov. Yellow diamonds represent records of type series, and white star locality of the holotype.

Tables

TABLE 1. Measurements in millimeters and proportions as percentage of total length for Scyliorhinus ugoi sp. nov. Mean (x), standard deviation (SD) and range of proportions (%).

	x SD	%	x SD	%
Total length (TL)	516 ±68.1	100	354.4 ±78.7	100
Precaudal length	393.7± 55.7	74.7–76.8	275.6 ±63.5	76.5–77.9
Eye-spiracle length	6.1 ± 1.3	0.9–1.3	3.3 ±1.2	0.6–1.3
Preoral length	23.8 ±4.7	4.3–5.6	16.9 ±3.2	4.3–4.7
Preorbital length	32.6 ±3.8	6.4	23.2 ±4.5	6.2–8.0
Prespiracular length	53.1 ±5.9	10.4–10.7	37.6 ±7.7	10.6–10.7
Prebranchial length	76.6 ±11.4	14.5–15.2	54.2±11.9	14.8–15.4
Head length	103.2 ±14.3	19.5–20.3	71 ±16.1	18.7–19.2
Prepectoral length	94.0 ±12.1	17.9	66 ±15.3	16.1–18.2
Prepelvic length	217.5±33.8	41.0–43.4	148 ±33.5	38.2–43.7
Snout-vent length	232.2±34.9	43.6–45.4	152 ±33.9	40.9–42.3
Vent-caudal length	262.5 ±43.4	53.7–55.3	189.6 ±40.9	51.3–58.3
Preanal length	314.1 ±50.3	59.1–64.4	213.2 ±51.4	55–62.7
Pre-first dorsal length	257.5 ±38.2	48.4–51.2	177 ±41.3	44.9–51.3
Interdorsal space	57.2 ±9.5	10.9–11.0	40.4 ±13.5	7.0–10.7
Dorsal-caudal space	22.3 ±4.7	4.2– 5.1	18.2 ±3.9	5.8–6.7
Pectoral-pelvic space	96.3 ±16.4	17.6–20.1	63.5 ±15.9	10–20.3
Pelvic-anal space	59.7 ±13.3	10.5–12.8	44.1 ±12.3	12.7–14.6
Anal-caudal space	39.2 ±5.6	7.4–7.6	28.5 ±6.5	8.7–8.9
Eye length	19.8 ±2.8	3.8–4.0	13.6 ±3.4	3.3–4.3
Eye height	3.8 ±0.3	0.9–1.4	4.7 ±1.1	1.3–1.5
Internarial space	10.1 ±3.6	1.4–2.4	9 ±3.4	2.0–4.0
Interorbital space	31.1 ±3.1	6.1–6.6	24.3 ±4.8	6.4–7.3
Spiracle length	4.3 ±1.1	0.4–0.9	2.6 ±1.1	0.6–1.3
Mouth length	23.5 ±5.0	3.7–5. 1	14.9 ±4.8	4.7–5.6
Mouth width	46.6 ±7.4	9.0–9.7	27.8 ±6.4	8.0
Lower labial furrow length	10.6 ±1.9	1.9–2.1	6.6 ±1.8	1.3–2.0
First gill slit height	15.2 ±2.7	2.8–3.1	9 ±2.3	2.0–2.8
Fifth gill slit height	8.6 ±2.3	0.9–1.8	4.7 ±1.3	1.3–1.9
Pectoral length	68.5 ±7.4	12.8–13.6	41 ±11.4	10.7–13.8
Pectoral anterior margin	74.6 ±9.0	14.5–15.0	47.5 ±11.9	12.7–15.6
Pectoral base	34.1 ±10.3	3.1–7.2	24.3 ±7.1	6.7–9.7
Pectoral posterior margin	45.6 ±6.3	8.7–9.0	30 ±8.8	5.3–8.9
Pectoral inner margin	32.2 ±2.3	5.9–7.1	21.9 ±5.8	5.3–7.6
Pelvic length	54.3 ±10.1	9.0–10.5	37.58 ±11.4	8.7–12.5
Pelvic inner margin	18.0 ±3.1	3.1–3.8	16.3 ±6.7	4–6.8
Pelvic base	38.0 ±11.0	6.4–8.9	24.4 ±6.6	4.7–8.0
Pelvic anterior margin	36.0 ±5.8	6.6–7.4	23 ±6.1	5.3–7.0
Pelvic posterior margin	33.6 ±4.8	6.4–6.6	22.7 ±7.2	3.2–7.4
Clasper outer length	20.3 ±4.5	3.8–4.1	16.8 ±8.1	2.0–6.2

TABLE 2. Measurements in millimeters and proportions as percentage of nasobasal length for Scyliorhinus ugoi sp. nov. Female (F), male (M), and range of proportions (% NL).

Nasobasal length (NL) Rostral length	54.3 14.6	100 20.8–29.3	51.5 12	100 22.4–24
Width across lateral rostral cartilages Width across nasal capsules Nasal capsule width	7.6 43.6 21.6	13.8–14.5 77.5– 85.4 37.9–43.7	6.5 40 21	12.2–13 76–79.6 40.8
Nasal capsule length Nasal aperture width Distance between nasal apertures	20.6 13.5 6.6	37.5–39.6 25–25.8 10.4–13.8	19 14 6.5	35.1–38.7 26.5–27.7 12.2–13