Brochiraja heuresa Last & Séret, 2012, sp. nov.
Creators: name: Last, Peter R.
name: Séret, Bernard
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Rajiformes
Arhynchobatidae
Brochiraja
Brochiraja heuresa

description: Brochiraja heuresa sp. nov.
(Figs. 1–7, 14; Table 1)
Notoraja sp. C (NFZ): Last, in Williams et al., 2006, Appendix 5: pp. 19, 21, 22, 24, 28, 31, 32 (listed); Appendix 5: p. 5 (6 photos n° 37031806), p. 6: (4 photos n° 37031806); Appendix 6: p. 1 (listed).
Holotype. CSIRO H 6073–01, adult male 355 mm TL, Wanganella Bank, Norfolk Ridge, 32°36.23’S, 167°47.09’E, 969– 926 m depth, RV Tangaroa, NORFANZ TAN 0308/123, bottom trawl, 31 May 2003.
Paratypes. 17 specimens from the Tasman Sea: AMS I 42763 –001, female 329 mm TL, same data as holotype; 2 specimens CSIRO H 6056–07, female 318 mm TL, CSIRO H 6056–08, female 342 mm TL, West Norfolk Ridge, 33°37.10’S, 166°55.50’E, 1017–1042 m depth, RV Tangaroa, NORFANZ TAN 0308/96, bottom trawl, 28 May 2003; CSIRO H 6064–01, female damaged, predorsal length 267 mm TL, Wanganella Bank, Norfolk Ridge, 32°36.30’S, 167°47.44’E, 1008–1029 m depth, RV Tangaroa, NORFANZ TAN 0308/111, beam trawl, 29 May 2003; CSIRO H 6067–02, female 286 mm TL, Wanganella Bank, Norfolk Ridge, 32°35.22’S, 167°47.66’E, 1025– 1052 m depth, RV Tangaroa, NORFANZ TAN 0308/114, bottom trawl, 30 May 2003; 3 specimens CSIRO H 6083–02, immature male 262 mm TL, NMNZ P. 39535, female 362 mm TL, NMV A 25171 –001, female 358 mm TL, West Norfolk Ridge, 34°14.33’S, 168°21.18’E, 1200– 1195 m depth, RV Tangaroa, NORFANZ TAN 0308/ 146, bottom trawl, 3 June 2003; 2 specimens CSIRO H 6089–02, adolescent male 341 mm TL, NMNZ P. 39639, adult male 379 mm TL, West Norfolk Ridge, 34°34.26’S, 168°56.53’E, 1013–1350 m depth, RV Tangaroa, NOR- FANZ TAN 0308/156, bottom trawl, 4 June 2003; CSIRO H 6091–01, female 364 mm TL, West Norfolk Ridge, 35°08.12’S, 169°28.37’E, 870–871 m depth, RV Tangaroa, NORFANZ TAN 0308/159, bottom trawl, 4 June 2003; 6 specimens CSIRO H 6072–01, adolescent male 358 mm TL, CSIRO H 6072–02, female 346 mm TL, NMNZ P. 39365 (2), juvenile male 324 mm TL, female 298 mm TL, MNHN 2010-1073, juvenile male 295 mm TL, NMV A 25164–007, female 273 mm TL, Wanganella Bank, Norfolk Ridge, 32°36.39’S, 167°50.59’E, 1345– 1331 m depth, RV Tangaroa, NORFANZ TAN 0308/121, beam trawl, 30 May 2003.
Diagnosis. A small species of Brochiraja distinguished by the following combination of characters: long tail, 1.2–1.3 times disc length, 2.4–2.5 times ventral head length, 4.9–6.0 times snout length; orbit moderately large, 2.7–3.4 in preorbital snout length; tail slender but with relatively broad conical base, evenly tapering to mid-length of tail, its width at pelvic-fin insertions 2.1–3.0 times width at midlength; anterior lobe of pelvic fin fleshy, spatulate; dorsal disc deceptively granular in appearance, covered with minute spiny denticles; mid-dorsal surface of tail with small thorns, surrounded by fine denticles; dorsolateral surface of tail lacking thorns; snout length 2.4–3.0 times distance from snout tip to weak rostral thorn; calcified rostral shaft short; single reduced preorbital thorn, posterior thorn weak or absent; ventral disc naked; anteroventral lateral margin of tail covered in fine denticles; alar thorns of mature males united to form a broad patch over most of outer anterior part of pectoral fin; no obvious malar thorn patch; lateral skin fold weak, somewhat expanded at level of dorsal fins, but width less than tail width, originating well behind middle of tail; dorsal surface pale bluish pink, ventral surface darker than dorsal surface, reddish brown; well-defined series of pale-edged pores on ventral surface, forming a whitish line adjacent anterior margin (disc distinctly darker lateral to this line); nuchal pore band not obvious; total pectoral radials 58–63; predorsal vertebrae 88–100; 30–42 tooth rows in upper jaw.
Description. Disc broadly suboval to roundish, becoming weakly heart-shaped in adult males, 1.12 in adult male holotype (1.12–1.17 in two adolescents and one adult male paratype, 1.12–1.17 in seven female and juvenile paratypes) times as broad as long; maximum angle in front of spiracles 102° (94–108°); anterior margin moderately double concave in holotype, almost straight to weakly concave opposite spiracles in paratypes; apex and rear tip broadly rounded, posterior margin moderately convex; axis of greatest width about 55% (54–56%, 54–56%) of disc length. Head moderately elongate, dorsal length 17.9% (16.2–17.8%, 16.1–17.0%) TL; snout broad, preorbital snout length 3.36 (3.00–3.30, 2.66–2.96) times orbit diameter, 3.12 (3.00–3.32, 2.72–3.06) times interorbital distance; preoral snout length 2.06 (1.94–2.14, 1.90–2.27) times internarial distance. Snout tip of adult male with well-developed, subtriangular, fleshy process, very small to rudimentary in juveniles and females; process distinctly demarcated from anterior profile of disc. Orbit large, elevated slightly, diameter 0.93 (1.00–1.10, 0.97–1.09) times interorbital distance. Spiracle moderately large; main pore covering most of spiracular depression, its length 1.73 (1.71–1.91, 1.78–1.97) in orbit diameter; its anteriormost extension well forward of hind margin of eye. Nostril irregularly oval, small, often distorted, with about 22 lamellae (paratype CSIRO H 6056–07); anterior nasal flap expanded laterally, partly concealed by nasal curtain anteriorly, forming weak tubular lobe along its lateral margin, posterior margin concealed beneath nasal curtain. Nasal curtain well developed, broader than long; its lateral margin strongly concave anteriorly (wrapping around anterior lobe), weakly expanded medially, then broadly rounded posterolaterally; labial margin weakly fringed; internarial distance 2.02 (2.02–2.15, 2.23–2.52) in distance between first gill slits, 1.22 (1.08–1.22, 1.25–1.56) in distance between fifth gill slits. Upper and lower jaws arched slightly at symphysis, much less so in females and juveniles. Teeth of male holotype small, in distinct rows, with slightly elevated crowns; crowns plate-like, suboval to quadrangular, with short, blunt cusps; cusps longest adjacent symphysis, directed posteriorly or posterolaterally in upper jaw, more or less anteriorly in lower jaw; more quincuncial in females and juveniles with very weak cusps.
Pelvic fin deeply incised; anterior lobe fleshy, relatively elongate, spatulate, broad along its entire length with a broadly rounded apex, inner margin weakly incised distally, more so near base; posterior lobe relatively short, with strongly convex, incised, lateral margin, inner margin short, straight to weakly convex, free rear tip bluntly acute to narrowly rounded; length of anterior lobe 0.78 (0.80–0.94, 0.83–0.90) times length of posterior lobe. Tail slender at base, tapering strongly posteriorly, pointed at its tip; width at insertions of pelvic fins 2.43 (2.44–2.54, 2.12–2.95) times width at midlength of tail and 3.18 (2.66–3.02, 2.52–3.43) times width at first dorsal-fin origin respectively; length from rear of cloaca 1.42 (1.44–1.47, 1.43–1.51) times distance from tip of snout to rear of cloaca; in cross section anteriorly, dorsal surface strongly convex, ventral surface convex and becoming almost flat posteriorly; no obvious median groove along basal third of tail on ventral surface; width 1.59 (1.47–1.58, 1.54–1.68) times height at insertion of pelvic fin, 1.61 (1.57–1.90, 1.48–1.90) times height at first dorsal-fin origin. Lateral skin fold weak, originating well behind middle of tail (about equivalent to predorsal length in advance of first dorsal-fin origin), terminating abruptly near mid-base of epichordal caudal-fin lobe; mainly narrow but broadest distally, width on each side equivalent to or slightly less than height of epichordal lobe of caudal fin. Dorsal fins small, short-based, very low, located near tail tip; first dorsal fin similar in size or slightly smaller than second, strongly raked, its apex usually over or slightly behind its insertion, first dorsal-fin height 3.72 (2.01–3.80, 2.18–3.29) times in its base length; second dorsal fin also strongly raked, posterior margin subequal in length or shorter than inner margin; fins close together, tip of first usually slightly overlapping second, interdorsal distance 4.25 (3.99–7.38, 4.65–7.42) times in length of first dorsal-fin base. Epichordal caudal-fin lobe relatively well developed, usually more than half height of first dorsal fin; distance from second dorsal-fin base subequal to interdorsal distance; hypochordal caudal-fin lobe relatively well developed, sometimes more than half height of epichordal lobe, its base about threequarters length of base of hypochordal caudal-fin lobe.
Dorsal surface of disc and posterior lobe of pelvic fins somewhat granular, denticles more or less evenly spaced, skin velvety to touch; extending along entire dorsal surface of tail; ventral surface of disc and pelvic fins entirely naked; denticles extending in a narrow band along anterior ventral margin of tail. Denticles unicuspid, with embedded, stellate bases (usually with 4 or 5 roots); cusps elongated, slender, pungent, mostly strongly recurved distally. Denticles on tail slightly larger and more robust than those on disc, more or less evenly spaced, no obvious naked patch beside median thorns (occasionally weakly formed on anterior part of tail), strongly recurved posteriorly; height of largest denticles almost equivalent to shortest median tail thorns; denticles irregular, not in defined rows; denticles on disc spindle-like, slender, with recurved tips. Dorsal and caudal fins uniformly covered with short, spiny denticles; isolated denticles present on lateral skin fold; anterior pelvic-fin lobe largely naked.
Thorns weak, confined to mid-snout, orbits, and midline of tail; alar patch present on anterior outer pectoral fin of mature males. Rostral thorn small (anterior length ca 0.5 mm in holotype, ca 1.2 mm in female paratype CSIRO H 6091–01), broad based (often embedded), with weak oblique, bifurcated crown (see Fig. 14); rudimentary to barely detectable externally in some paratypes; located forward on snout, its distance from snout tip about 2.43 (2.86–3.02, 2.47–2.97) in preorbital snout length. Preorbital thorn single, rudimentary, short, subconical, tips mainly upright, often obscure; postorbital thorns absent in holotype, weak, short in some paratypes; orbital thorns barely taller than longest denticles adjacent, anterior thorn aligned with anterior orbital margins. Thorns on dorsal midline not forming an obvious series; usually similar in height but with longer bases than largest adjacent denticles; not in an obvious regular row; bases of thorns compressed and subtriangular when viewed laterally. Alar thorn patch broad; non-retractable, posteromedially directed thorns in a few longitudinal rows on mid-outer pectoral fin; thorns grading into a patch of similar, more posteriorly directed thorns of variable size; malar thorns not obvious.
Rostral cartilage (based on radiographs) poorly developed, narrow basally, calcified component short, extending anteriorly to about rostral thorn; rostral appendices and rostral shaft not visible; dorsal surface of shaft not greatly elevated above appendices; anterior fontanelle broadly flask shaped, extending onto rostral cartilage well anterior to leading edge of nasal capsules; propterygium of pectoral girdle reaching to base of rostral node; lateral prepelvic processes of pelvic girdle prominent. Claspers long, slender, postcloacal length 19.8% (20.1%) TL when mature; glans little expanded, bluntly pointed distally, distal aperture moderately large; configuration similar to other members of the genus as in Last & McEachran (2006); tip of ventral marginal cartilage claw-like, pungent.
continued next page Brochiraja heuresa Brochiraja vittacauda
Holotype Paratypes Holotype Paratype
Male Males (n=3) Females (n=6) Male Male (immature)
MIN MAX MIN MAX
Tail at midlength (height) 1.2 1.2 1.2 1.2 1.4 1.0 1.0 Tail at D1 origin (width) 1.4 1.3 1.5 1.3 1.6 1.5 1.1 Tail at D1 origin (height) 0.9 0.8 0.8 0.8 1.0 0.8 0.8 D1 base length 4.5 3.0 3.9 3.4 3.8 3.2 2.9 D1 height 1.2 1.0 1.5 1.2 1.7 1.5 1.2 D1 orig to caudal-fin tip 13.9 12.4 14.9 13.8 14.5 11.9 13.7 D2 orig to caudal-fin tip 8.9 8.5 10.0 9.3 10.2 7.1 8.7 Caudal-fin length 4.7 3.8 5.3 4.5 5.6 2.0 4.0 Interdorsal distance 1.1 0.5 1.0 0.5 0.8 1.4 1.7 Distance - rostral thorns to snout tip 4.9 3.6 4.0 3.5 4.2 4.7 2.9
Tooth rows in upper jaw 33 (30–42, n=14); lower jaw 32 (28–39). Pectoral-fin propterygial radials 30 (27–32, n=17); mesopterygial radials 9 (8–11); metapterygial radials 22 (19–23); total radials 61 (58–63). Monospondylous centra 22 (22–26, n=17); predorsal caudal centra 73 (65–76); predorsal centra 95 (88–100, mainly 93–98); total centra 135 (134–145, n=3).
Coloration. In holotype (when fresh), dorsal surface of disc, posterior lobe of pelvic fin and tail pale bluish pink; anterior lobe darker reddish brown, contrasted strongly with posterior lobe; eyes blackish; clasper whitish with dusky posterolateral margin. Ventral surface of disc reddish brown; mouth whitish; sensory pores pale, well developed, particularly on snout; prominent line of almost continuous pores adjacent anterior margin of disc, part of disc lateral to this line distinctly darker than inner part; similar dark patches around branchial region, almost completely encircled by line of small, pale pores; four pores at edges of abdomen; anterior pelvic-fin lobe greyish brown, darker than posterior lobe; cloaca pale; tail piebald, variable brownish and white.
In preservative, dorsal disc usually bluish grey with yellowish areas, and peppered with clusters of melanophores at bases of denticles; dorsal tail mostly yellowish; anterior lobe of pelvic fin, margins of posterior lobe, disc, lateral skin fold, and dorsal and caudal fins blackish. Ventral surface dark greyish brown, much darker than dorsal surface; pores strongly defined, whitish; mouth and gills whitish. Some paratypes (i.e. NMNZ P. 39639) are darker bluish pink dorsally in preservative.
Size. Small skate with adult males reaching at least 379 mm TL, two males adolescent were 341, 358 mm TL; largest female 364 mm TL.
Distribution. Known from deep banks and ridges of the northern Tasman Sea, including the western Norfolk Ridge and the Wanganella Bank (ca 32°35’– 35°08’ S, 166°56’– 169°29’ E), at 870–1350 m depth (see Fig. 15).
Etymology. During the NORFANZ voyage, an attempt was made to collect additional specimens of the then ‘soon to be described’ Enigma Skate (Brochiraja aenigma). The unique type specimen of B. aenigma Last & McEachran, 2006, which was collected some 22 years before from the Wanganella Bank, was in poor condition. Seven demersal trawl stations at depths of about 870–1350 m yielded several small skates that were initially thought to be additional specimens of the Enigma Skate. However, on closer inspection they turned out to be another undescribed species. The epithet is derived from the Greek heuresis (that which is found, discovered), based the Ancient Greek word Heureka (meaning ‘I have found it’) or in modern English, simply ‘eureka’! Vernacular name: Eureka Skate.
Comparisons. Superficially similar to Brochiraja aenigma, which also occurs on the Wanganella Bank and is known only from the holotype. However, despite their superficial similarity, these species differ in many aspects. For example, Brochiraja heuresa has a less rounded disc than B. aenigma, shorter tail (its length 1.2–1.3 vs. 1.5 times disc length, 2.4–2.5 vs. 2.9 times ventral head length, 4.9–6.0 vs. 6.8 times snout length), smaller eye (orbit length 2.7–3.4 vs. 2.4 in preorbital snout length), relatively longer dermal denticles on upper disc and tail, weak orbital thorns (vs. thorns absent), more obvious pale pores on the ventral surface, a darker dorsal and ventral surface, fewer pectoral radials (58–63 vs. 73–74), and fewer vertebrae (predorsal centra 88–100 vs. 115).
Of other members of the genus, only B. spinifera and B. microspinifera have the dorsal disc largely covered in small denticles. However, Brochiraja microspinifera and B. heuresa are much smaller skates (adult males 27–33 cm TL and 36–38 cm TL respectively) than B. spinifera (61–71 mm TL, Last & McEachran, 2006). Brochiraja heuresa has a relatively smaller eye than B. microspinifera (2.7–3.4 vs. 2.1–2.8 in preorbital snout length), shorter interdorsal distance (0.5–1.1% vs. 1.2–3.1% TL), rostral thorns positioned further forward on the snout (snout length 2.4–3.0 vs. 1.8–2.1 times their distance from snout tip), dorsal surface of disc and tail with a much denser coverage of denticles (those on disc also relatively longer), postorbital thorn sometimes present (vs. absent), dorsal disc bluish (rather than dark brownish), more obvious whitish pores on the ventral surface, more vertebrae (predorsal centra 88–100, mainly 93–98 vs. 81–88). Brochiraja heuresa differs from B. spinifera in size and morphometrics, as well as having less obvious nuchal pore patches and many more vertebrae (predorsal centra 71–82).
description: Published as part of Last, Peter R. & Séret, Bernard, 2012, Two new softnose skates of the genus Brochiraja (Rajoidei: Arhynchobatidae) from the deepwater slopes and banks of the Norfolk Ridge (South-West Pacific), pp. 47-64 in Zootaxa 3155 on pages 48-56, DOI: 10.5281/zenodo.279614