Pavoraja umbrosa, Last, Peter R. & Yearsley, Stephen Mallick And Gordon K., 2008

Last, Peter R. & Yearsley, Stephen Mallick And Gordon K., 2008, A review of the Australian skate genus Pavoraja Whitley (Rajiformes: Arhynchobatidae), Zootaxa 1812, pp. 1-45: 37-42

publication ID

http://doi.org/ 10.5281/zenodo.182801

persistent identifier

http://treatment.plazi.org/id/CC226640-DA5D-FFA3-FF78-79C2FA82BBB4

treatment provided by

Plazi

scientific name

Pavoraja umbrosa
status

sp. nov.

Pavoraja umbrosa  sp. nov.

( Figs 1View FIGURE 1 f, 2 f, 20 d –f, 21–23, Tables 3, 4)

Pavoraja  sp. F: Last and Stevens, 1994, Sharks and rays of Australia, pp 319, fig. 34.13, key fig. 42, pl. 46; Last and Compagno, 1999, Arhynchobatidae  , softnose skates. In: Carpenter and Niem (eds), 1999, FAO species identification guide for fisheries purposes. The marine living resources of the Western Central Pacific, pp 1461, figs.

Holotype. CSIRO T 1367, 351 mm TL, adult male, off Stradbroke Island, Queensland, 27 ° 40 ' S, 153 ° 56 ' E, 530 m, 22 Nov. 1982.

Paratypes. 28 specimens (83–369 mm TL): AMS I 19093View Materials –005 (5 specimens), 83 mm TL, juvenile male; 107 mm TL, female; 113 mm TL, female; 115 mm TL, female; 140 mm TL, female, off Wooli, New South Wales, 29 ° 52 ' S, 153 ° 43 ' E, 503 m, 10 Oct. 1975; AMS I 20301View Materials –023 (11 specimens), 90 mm TL, female; 94 mm TL, juvenile male; 99 mm TL, juvenile male; 128 mm TL, female; 233 mm TL, female; 241 mm TL, juvenile male; 270 mm TL, juvenile male; 302 mm TL, female; 306 mm TL, female; 306 mm TL, adolescent male; 334 mm TL, female, off Wooli, New South Wales, 29 ° 53 ' S, 153 ° 42 ' E, 502 m, 23 Aug. 1977; AMS I 21776View Materials –006, 250 mm TL, female, off Danger Point, Queensland, 28 °02' S, 153 ° 57 ' E, 410 m, 1 Jun. 1978; AMS I 21777View Materials –004 (3 specimens), 206 mm TL, juvenile male; 272 mm TL, juvenile male; 335 mm TL, female, off Danger Point, Queensland, 28 °06' S, 153 ° 58 ' E, 410 m, 1 Jun. 1978; AMS I 21789View Materials –003, 302 mm TL, juvenile male, off Danger Point, Queensland, 27 ° 55 ' S, 154 °03' E, 548 m, 6 Nov. 1978; AMS I 21795View Materials – 0 11, 329 mm TL, female, off Danger Point, Queensland, 28 °03' S, 154 °04' E, 731 m, 6 Nov. 1978; CSIRO H 157 –01, 349 mm TL, adult male, east of Wooli, New South Wales, 29 ° 50 ' S, 153 ° 41 ' E, 360 m, 18 Jul. 1982; CSIRO T 1363, 369 mm TL, adult male; CSIRO T 1364, 309 mm TL, female, east of Moreton Island, Queensland, 27 ° 12 ' S, 153 ° 52 ' E, 555 m, 10 May 1983; CSIRO T 1365, 300 mm TL, juvenile male, off North Stradbroke Island, Queensland, 27 ° 35 ' S, 153 ° 57 ' E, 545 m, 31 Mar. 1983; CSIRO T 1366, 319 mm TL, female, off North Stradbroke Island, Queensland, 27 ° 19 ' S, 153 ° 53 ' E, 600 m, 10 May 1983; CSIRO T 1368, 304 mm TL, adolescent male, off North Stradbroke Island, Queensland, 27 ° 35 ' S, 153 ° 57 ' E, 545 m, 31 Mar. 1983.

Diagnosis. A species of Pavoraja  with: with a relatively long, narrow tail, length 56–60 % TL, width at midlength 1.3–1.8 % TL; large orbits, diameter 4.3–5.4 % TL; broad nasal curtain, total width 6.7–7.6 % TL; orbital thorns large, mostly 3 on posteromedial margin; interorbital usually absent; spiracular and scapular thorns absent; nuchal pore patch indistinct, not preceded by a nuchal thorn; thorns of tail series normally absent near first dorsal fin, lateral series often absent; dorsal fin placement variable, fins confluent to widely spaced; epichordal lobe of caudal fin not confluent with second dorsal fin, base of lobe equal to in length or shorter than dorsal-fin bases; tooth rows in lower jaw 36–42; predorsal caudal centra 74–83; interdorsal vertebrae 10–13; pectoral radials 68–71; greyish brown, often with darker dusky blotches, lacking pattern of white spots; dorsal fins uniformly greyish to blackish; epichordal lobe pale to dusky, not strongly demarcated from dorsal fins; ventral surface mostly dark.

Description. Disc 1.15 (1.07–1.19) times as broad as long; maximum angle in front of spiracles 103 ° (94– 101 °); anterior margin weakly convex to double concave in females and immature males, deeply concave opposite spiracles in males; posterior margin strongly convex; outer corners broadly rounded. Snout width at axis through anterior border of orbits 60 % (63–65 % in mature male, 71 % in female paratypes) of distance from tip of snout to axil of pectoral fins. Pelvic-fin anterior margin 72 % (74–88 %) of distance from origin of anterior lobe to posterior extremity of fin. Tail length 1.25 (1.10–1.37) times disc length; widths at midlength and at axils of pelvic fins 32 % (25–34 %) and 84 % (73–84 %) of orbit diameter respectively; skin fold very narrow anteriorly, extending along ventrolateral surface from near pelvic-fin tip to near origin of hypochordal lobe of caudal fin, much wider beneath dorsal fins (subequal or slightly exceeding height of epichordal lobe of caudal fin). Interdorsal distance variable, interdorsal membrane continuous or fins separated by as much as epichordal lobe length; epichordal caudal-fin lobe separated slightly from base of second dorsal fin (by a distance of up to base length of lobe), base shorter than bases of dorsal fins.

Preocular length 2.08 (2.09–2.53) times longer than orbit diameter; preoral length 2.40 (2.19–2.55) times internarial distance. Orbit diameter 1.57 (1.66–1.95) times interorbital distance; 2.12 (1.69–2.18) times length of spiracles. Internarial distance 0.44 (0.40–0.48) in distance between first gill slits; 0.78 (0.66–0.85) in distance between fifth gill slits. Length of first gill slit 1.41 (1.26–1.50) times length of fifth gill slit; 0.18 (0.17– 0.20) in mouth width.

Dorsal surfaces of disc, tail and posterior lobes of pelvic fins densely covered with granular denticles. Dorsal fins denticulate. Claspers, anterior lobes of pelvic fins, skin folds on tail, caudal lobes and entire ventral surface naked. Orbit with 2–4 thorns on anteromedial margin, 1–4 (mainly 3) on posteromedial margin (often damaged); one interorbital thorn rarely present; interspiracular and scapular thorns absent. Prenuchal and nuchal thorns 0–4 (holotype damaged, mainly 2 or 3 in paratypes), situated posterior to pale, pored prenuchal area; thorns well developed, prominent when undamaged. Tail with 1–3 (mainly 3) series of thorns; dorsolateral series short, variable (usually absent in specimens <240 mm TL), rarely extending onto disc, sparse or absent on posterior half of tail, thorns often staggered; median series more regular, never extending onto disc, rudimentary or absent before dorsal fins; interdorsal thorns never present. Adult males with 2–3 irregular rows of small non-retractable alar thorns; alar thorns sometimes paired, not forming a dense patch; malar thorns much smaller, situated anterolaterally to alar thorns, patch extending anteriorly well short of greatest concavity of anterior margin of disc, to about level of pectoral-fin apex. Smallest juvenile (AMS I 19093View Materials – 005): disc uniformly granular, no obvious orbital or nuchal thorns; tail thorns in a linear median row, equally Claspers slender ( Figs 20View FIGURE 20 d –f); pseudorhipidion continuing distally under sentinel as fold of integument, finally becoming fused to glans floor; spur well developed though proximal section poorly defined, distal tip slightly recurved, lying inside glans margin; rhipidion moderately well developed, extending from middle to distal one-third of glans, proximal section very thin, thicker distal section lying over base of sentinel; sentinel well developed, oval, covered by integument which is thicker and more fleshy over lateral region, extending from level of slit to past tip of glans; spike hidden within sentina; axial cartilage straight, slender; dorsal marginal not expanded distally; pseudorhipidion rod-shaped though thickened before thinning distally to a point; ventral marginal with an evenly convex distal margin; dorsal terminal 1 and ventral terminal cartilages narrowly joined on ventral aspect of glans or connected by tissue, together forming sheath-like covering over central half of glans; dorsal terminal 1 membranous; ventral terminal mostly membranous, with thickened area immediately distal to short proximal arm, penetrating glans and lying against dorsal margin of proximal extension of accessory terminal 1; dorsal terminal 2 with poorly defined cartilaginous projection joined to axial near level of accessory terminal 2 base by connective tissue (incomplete terminal bridge), lateral margin irregular; dorsal terminal 3 moderately large; accessory terminal 1 with a bow-shaped distal extension forming sentinel, extending slightly past distal margin of accessory terminal 2.

Neurocranium of CSIRO T 1364 typical of genus; with very small accessory lateral cartilages; 2 foramina near apex of rostral node; rostral shaft relatively long, longer than length of basal fenestra and extending about halfway to rostral base; posterior fontanelle slightly longer than anterior fontanelle.

Scapulocoracoid expanded anteriorly, with 2 postventral foramina; extra condyle sometimes present on neopterygial ridge.

Meristics (n= 6). Tooth rows in upper jaw 41 (36–46), in lower jaw 42 (36–42). Vertebral counts: monospondylous centra 28 (27–30), predorsal caudal centra 80 (74–83), interdorsal centra 12 (1–13), diplospondylous centra 116 (106–117), total centra 144 (134–147). Pectoral-fin counts: propterygial radials 32 (31–33), mesopterygial radials 12 (11–14), metapterygial radials 26 (23–27), total radials 70 (68–71). Pelvic-fin counts: males 4 (3–4) + 19 (17–19) radials, females 3 + 19–20 radials.

Coloration. Preserved and live colours similar. Dorsal surface of disc, tail and posterior lobes of pelvic fins medium brown to dark brown, usually slightly mottled, with large, diffuse-edged dark brown blotches, no light-coloured spots but sometimes with indistinct paler blotches; membrane covering orbit semi-translucent to slightly pigmented; mid area of snout and outer part of disc only slightly paler than central part of disc; nuchal pore patch indistinct, not demarcated by a pale blotch; lateral skin fold dusky to almost black distally. Claspers brownish dorsally with blackish lateral margin, posterolateral extremity of glans white, dusky ventrally. Dorsal fins generally uniformly greyish to blackish; epichordal lobe of caudal fin dusky to pale, not usually strongly demarcated from dorsal fins. Ventral surface relatively dark, dark brownish to greyish; paler areas on snout, oronasal region, gill slits, cloaca and sometimes basal half of anterior pelvic-fin lobe; darkest areas between gills and around pectoral-fin corners; tail variably coloured with white and dark areas. Smallest juveniles (<100 mm TL) with fine black spots on disc (plain coloured in one paratype from AMS I 19093View Materials – 0 0 5,> 110 mm TL); predorsal tail with irregular spotting and indistinct bands; prominent dark band below dorsal fins; ventral surface translucent or white.

Size. At least 369 mm TL and about 191 mm disc width. Smallest mature male 349 mm TL. Smallest post-natal juvenile 83 mm TL.

Distribution. Upper continental slope off eastern Australia, between east of Wooli, New South Wales (29 ° 53 ' S, 153 ° 42 ' E) and east of Moreton Island, Queensland (27 ° 12 ' S, 153 ° 52 ' E), in depths of 360– 731 m.

Etymology. From the Latin umbrosus (shady) in allusion to the uniform greyish dorsal surface of the disc.

Comparisons. Pavoraja umbrosa  is similar morphometrically and meristically to its eastern Australian congener, P. pseudonitida  , but lacks interorbital thorns (sometimes present in P. pseudonitida  ), the dorsal surface is greyish without small white spots (otherwise spotted), the ventral surface is dusky (rather than pale), and the epichordal lobe of caudal fin is mainly dusky and is not usually strongly demarcated from the dorsal fins (in P. pseudonitida  the dorsal fins are strongly contrasted against a pale epichordal lobe). Pavoraja umbrosa  differs from other members of the genus by combinations of characters given in the key and diagnoses.

Remarks. Pavoraja umbrosa  belongs to the Central Eastern marine biogeographic province of Australia where it is found primarily in the upper slope and mid –upper slope biomes ( Last et al., 2005).

P. pseudonitida  sp. nov. P. umbrosa  sp. nov.

Holotype Paratypes Holotype Paratypes

Min. Max. Mean Min. Max. Mean

Total length (mm) 372 250 370 351 300 369

CSIRO

Australian National Fish Collection