Rajella lintea Fries 1839, new combination
Creators: name: Stehmann, Matthias F. W.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Rajiformes
Rajidae
Rajella
Rajella lintea

description: Rajella lintea (Fries, 1839), new combination
Raja lintea Fries, 1839. Holotype: stuffed female NRM 206a, but probably lost. Synonyms: Raja ingolfiana Lütken, 1898; Raja (Dipturus) lintea of McEachran and Miyake (1990); Dipturus linteus (Fries, 1838) of McEachran and Dunn (1998).
Diagnosis. A medium-sized amphi-North Atlantic rajid species of genus Rajella growing to at least 125 cm TL. Tail length from mid-anus to tip nearly equal to body length; dorsal fins with bases mostly confluent; postdorsal tail section very short. Clasper postanus length of mature male less than 40% of tail length, with only terminal region exceeding tip of posterior pelvic lobes. Sides of tail very densely covered with a band of dermal denticles and sharply delimited from smooth back of tail along the course of median thorns. A regular median row of 39–44 close-set large thorns persisting from smallest young onward from directly behind shoulder girdle to first dorsal fin; a regular row of 50–60 strong, hooked thornlets along each lower edge of tail persisting from smallest young onward. Upper side uniformly, rather dark greyish-brown; underside largely creamy-white, but with constant brownish colour markings; sensory and mucus pores on both surfaces not marked black. Clasper lacking external pseudosiphon; inner dorsal lobe with components slit, “pseudorhipidion”, terminal bridge and cleft; inner ventral lobe with components slit, shield, dike, rhipidion, sentinel and spike. Terminal clasper skeleton with six dorsal terminal, three accessory terminal cartilages and ventral terminal, all of genus specific shape and configuration. Anterior cranial fontanelle with clear-cut contour all around and extending about one third into rostral shaft length. Scapulocoracoid subrectangular, with rear corner rounded and not sharply marked; large oval anterior fenestra without anterior bridge, one large subcircular postdorsal and one lower large oval postventral fenestra. Pelvis with thick, nearly straight ischiopubic bar and short, solid conical prepelvic processes inclined outward.
Description (Figs. 1–21). Detailed morphometrics and meristics given in Table 1.
External morphology (Figs. 1–9): disc evenly inverse heart-shaped, with anterior margins almost straight to slightly convex, moderately undulated in mature males, outer corners rounded, posterior margins convex and inner corners broadly rounded; disc width 1.2 times disc length, axis of maximum disc width at 32–38% of TL or 61– 67% of disc length at about level of, or shortly posterior to shoulder girdle. Dorsal head length about one fifth of TL. Snout tip not pronounced, narrowly rounded; snout pointed at about 90–100° angle, the narrower angle in larger specimens and mature males, and moderately elongated with preorbital length 2.7–3.3 times the interorbital width. Orbit horizontal diameter equal to interorbital width; spiracle depression/aperture proper lengths 36.2– 74.5% and 23.4–46.8% of orbit horizontal diameter, resp.; interspiracular space 1.5–1.7 times the interorbital width; 10–11 pseudobranchial folds in each spiracle. Tail solid, broadly trapezoid in cross-section and gradually tapering to tip; its length from mid-anus to tip nearly equal to body length from snout tip to mid-anus (0.9–1.1); relation tail width to height at level of pelvic tips 1.3–1.9, at level of first dorsal fin origin 1.4–1.8; both dorsal fins of nearly equal size and shape, almost twice as long as high and parallelogramm-shaped, with broadly rounded to horizontal upper margin; relation base length to height 1.6–2.3 (D1) and 1.4–2.0 (D2); their bases mostly confluent, sometimes with very short interspace; postdorsal tail section very short, just one fifth to one half of D2 base length; epichordal caudal lobe confluent with D2 base end and not overhanging tail tip, mostly distinct but very low with only 1/10–1/12 of D2 height; hypochordal caudal lobe lacking, at most occasionally a low ridge present (Fig. 2). Lateral tail folds moderately distinct, usually along posterior half or one third of tail only.
Ventral head length about one third of TL. Preoral snout length 1.7–2.3 times (mean 2.1 times) the mouth width, snout relatively shorter in large specimens; mouth width 25.2–36.0% (mean 28.7) of ventral head length and about equal (0.9–1.1 times) to internarial space; ventral head length 2.8–3.9 times (mean 3.6) the internarial width; distance between 5th gill slits 63.2–72.4% of distance between first gill slits, which latter nearly twice (1.8–1.9 times) the internarial space; anterior nasal flaps rather small and smooth-edged; outer edges of nasal curtain in general distinctly convex but with a weak indentation in proximal half, without a marked lateral lobelet; apices angular, straight to somewhat diagonal posterior margins set with coarse fringes, tips of which partly bifurcated; isthmus an even deep arc. Jaws straight in both sexes and at all sizes; 41–50 close-set parallel tooth rows in upper jaw; individual tooth with low subcircular to rhombic base and short, conically pointed cusp, which more elongated in mature specimens (Fig. 3). Pelvic fins outer margin deeply notched, separating short thumb-like anterior lobe with blunt tip from elongated posterior lobe with strongly convex outer margin and narrowly rounded tip, which pointed rather in mature male; posterior lobe 1.3–1.9 times the length of anterior lobe, the higher values in adolescent and mature males. Clasper postanus length of mature male 36.3% of tail length, with only terminal region exceeding tip of posterior pelvic lobes (Fig. 4).
Values given by Bigelow and Schroeder (1953) of an adult couple agree well with those given in Table 1, especially for the mature male.
Squamation (Figs. 1, 5–8): upper disc wholly and loosely set with coarse dermal denticles, also eyeballs prickly in specimens up to 50 cm TL, and pelvic fins smooth at all sizes; centre of disc and eyeballs becoming gradually smooth in larger specimens, with only a marginal band of dermal denticles around disc remaining, and in large specimens of both sexes a patch of thornlets and small thorns opposite eyes at outer margin (Fig. 5); claspers smooth dorsally; sides of tail very densely covered with a band of fine (finer than those on disc) dermal denticles and sharply delimited from smooth back of tail along the course of median thorns (Fig. 6), and both dorsal fins prickly in upper parts; underside of disc, pelvic fins, claspers and tail totally smooth, except for often a few coarse dermal denticles embedded medially near snout tip.
continued next page About 10 distinct thornlets in irregular double row on anterior half of rostrum in smaller specimens, increasing to about 40 thornlets as a band in large ones; orbital thorns separated at smaller size, with one big inner and one small outer preorbital thorn, a small one supraorbitally, a large one postorbitally, 1–2 small or large ones in supraspiracular and constantly a pair of conical thorns more inward in interspiracular position; large specimens show in addition a patch of thornlets pre- and postorbitally (Fig. 5); 2–4 large median nuchal thorns, first one smaller, followed by 1–2 large suprascapular thorns, and mostly three thorns on each shoulder, with inner one the biggest; a regular row of 39–44 (33 only in a neonate described below) close-set large thorns with sharp, recurved tip from directly behind shoulder girdle to first dorsal fin, of which 9–11 (mostly 10, but only 6 in a neonate) on back of trunk to level of pectoral axils; no thorn between dorsal fins, even if these separated by small interspace; basal cones of all thorns distinctly ribbed; median thorn row persisting from smallest young onward, but tips become abraded in fully grown specimens on trunk and in anterior half of tail, and the basal cones tend to split up by radiated cracks (Fig. 7). A regular row of 50–60 strong, hooked thornlets along each lower edge of tail persisting from smallest young onward (Figs. 4, 6). Mature males with an elongated field of strong alar thorns across wing tips consisting of three longitudinal and 29–31 transverse rows of sharp, claw-like thorns which erectile from individual dermal pockets; additionally with a band of thornlets at anterior disc margins from level of half snout length to the begin of the elongated alar thorn field (Fig. 8).
Distribution of squamation components, pattern and number of thorns well in agreement with the description by Bigelow and Schroeder (1953).
Colouration (Figs. 1, 9): upper side uniformly, rather dark greyish-brown, eyeballs dusky-bluish; edges of disc, pelvic fins and dorsal fins narrowly edged creamy-white. Underside largely creamy-white, but with constant brownish colour markings, namely with a broad more or less dark margin from wing tips to pectoral axils and on posterior pelvic lobes, a dark blotch on tip of anterior pelvic fin lobe, a pair of large, oval to bean-shaped blotches flanking cloaca, and a broad dark median stripe along entire tail, edges of which are creamy (Fig. 9); variation on underside of tail does occur, with instead of solid median dark stripe an irregular double row of brownish specks of varying sizes medially along anterior half or nearly entire tail. Claspers ventrally edged with brown encroaching from upper side at inner margin over whole length, except for terminal region, and also along outer margin, except for distal third of terminal region; broad median part white.
Clasper external morphology (Figs. 4, 10): massive and relatively short with about 40% of tail length only; the terminal region only exceeding posterior pelvic fin tips and little wider than clasper stem; clasper tip narrowing abruptly distally to form a spatulate, bluntly rounded end; ventral glans lobe broader than dorsal lobe and visible in dorsal view, as marked by dark colour edge along outer margin of the largely white ventral lobe. Pseudosiphon lacking along outer external surface of dorsal lobe, but outer surface with a depression at proximal half of terminal region, marked by prominent longitudinal integumental folds (Fig. 4). Inner dorsal lobe with transverse proximal slit (sl) spanned between longitudinal plate-like pseudorhipidion-like cartilage (pseudo-pr) and outer lobe margin; a deep longitudinal cleft (cf) along distal half of lobe bordered by inner terminal bridge (tb) and outer lobe wall supported by dorsal terminal cartilages. Inner ventral lobe with a proximal slit (sl), out of which the prominent but narrow shield (sh), with sharp cutting outer edge of free cartilage, runs along entire outer margin of lobe; shield in distal half trough-like and covered with lamellated tissue along the central groove, its inner nearly vertical wall forming component dike (dk); proximal inner end of shield forms a subtriangular large protuberance covered by thin integument; a distinct fan-shaped rhipidion (rh) with deeply porous surface along inner proximal third of lobe, parallel to the dorsal lobe pseudorhipidion-like structure; in median third of ventral lobe, distal of rhipidion, two finger-like components covered by thick fleshy tissue, the sentinel (st) and underneath of it the spike (sk); component ‘pent’ lacking (Fig. 10).
Clasper skeleton (Figs. 11–17): beta-cartilage (β) on head of axial cartilage (ax) very large, its length more than one third of dorsal marginal cartilage (dm) length, its proximal half subovally widening. Narrowly strapshaped dorsal marginal (dm) extending along proximal two thirds of clasper, with somewhat narrowing, bluntly pointed proximal end level with head of axial, and a slight widening, after deeply concave marginal indentation, to trapezoid distal end (Fig. 11 a). Dorsal terminal 1 cartilage (dt1) rather narrowly strap-shaped, running diagonally across proximal two thirds of terminal skeleton, widening toward axial and curving around axial onto ventral side, where flexibly connected by tissue with narrow distal extension of ventral terminal cartilage (vt) (Figs. 12 b, 13). Underneath solid, rectangular dorsal terminal 2 (dt2), fused with entire dorsal marginal’s distal edge, a thin strapshaped free dorsal terminal cartilage (free dt) linked with the dorsal marginal medially and appearing externally as a pseudorhipidion-like structure (pseudo-pr) (Figs. 10, 12 a). Dorsal terminal 3 cartilage seemingly bifurcated and fused with outer half of dorsal terminal 2 distal edge; short and solid, distally bifurcated inner dt3 “branch” connecting as terminal bridge (tb) cartilage with the axial, the outer “branch” is the thin, plate-like, distally pointed dt3 which is about twice as long as the tb-cartilage (Figs 14 a–c, combining dt2, dt3, tb). The long, convex plate-like dorsal terminal 4 cartilage is attached over the proximal end of the dt3-cartilage, totally overlies the latter and is distally linked laterally with the spatulate tip of the axial cartilage (Fig. 12 a). Ventral marginal cartilage (vm) platelike solid, proximally shorter than dorsal marginal, its proximal end pointed, the distal third widening, twisting to horizontal level and curving with distal inner margin a little around the axial (Fig. 11 b). Ventral terminal cartilage (vt) (Fig. 15) narrow and very elongated, extending from level of distal vm-third longitudinally over proximal two thirds of terminal region as the latter’s outer margin; distally turning a bit inward with pointed short ‘funnel-like’ process not showing externally as this component, toward the broadly rounded ventral side edge of dorsal terminal 1 (Figs. 11 b, 12b); ventral terminal’s distal half shows in ventral view an outer cartilaginous lamella narrowing proximally and forming externally the razorblade-like sharp cutting edge of the shield; distal third of vt in dorsal view with broad lateral extension of groove-like shape, with the almost vertical inner wall of the groove forming external component dike (dk); in ventral view, distal third of vt appearing elevated as a prominent convex ridge terminating proximally as a massive, prominent, conical process linking vt with the ventral surface of at1 cartilage; median third of vt abruptly narrowing, but continuing in dorsal view the distal deep groove by becoming shallower proximally, and in ventral view its median third appears as a shallow ridge running out on the flat proximal third of vt; proximal third of vt in dorsal view curving somewhat outward as a narrow pointed tip, with a subtriangular massive inner plate-like extension laterally, also prominent as an external structure just proximal to the rhipidion (Fig. 10). Accessory terminal 1 cartilage (at1) (Fig. 16) typically asymmetrically Y-shaped, with its much longer fingerlike outer branch fused around distal and lateral edge of ventral marginal, and overlying the proximal half of the ventral terminal; distal part of at1 a long extension narrowing rapidly underneath distal end of vt toward outward and downward curving and hook-like twisted tip, appearing externally as fleshy-mantled component sentinel (st) (Fig. 10). The accessory terminal 2 cartilage (Fig. 17) is fused with the very inner distal edge of ventral marginal cartilage, shows in ventral view an oval, deeply concave surface underneath the at1, into which the inner edge of at1 fits; distally, the at2 is bifurcated and twisted, curving outward as a pointed tip appearing externally as fleshymantled component spike (sk), whereas the lower, shorter branch is plate-like trapezoid and not forming an external component (Fig. 10) but linked with an elongated, bean-shaped at3 cartilage along the inner margin of the axial’s spatulate tip (Fig. 12). In total, the terminal clasper skeleton consists, besides the central axial and both marginal cartilages, of six dorsal terminal (including free dt-cartilage linked with the dorsal marginal, and the tb-cartilage) and three accessory terminal cartilages, plus the ventral terminal.
Cranium (Fig. 18): Stehmann (1970: pl. 26) had already published drawings of a dissected R. lintea cranium in dorsal, ventral and lateral views (ZMH 101203) showing a rostral node with short and relatively wide rostral appendices (vs. narrow, elongated appendices in Dipturus); an all around clear-cut anterior fontanelle of elongated oval shape with pointed tip and somewhat narrowing quadrate posterior end, extending about one third of rostrum length into rostral shaft (vs. very elongated anterior fontanelle without defined anterior end, but instead running out as a shallow groove on rostral shaft at more than half rostral length in Dipturus); posterior cranial fontanelle much narrower than anterior one, with pointed anterior end, two slight constrictions over its length, which is somewhat less than half the length of anterior fontanelle (vs. bluntly rounded anterior end, a median constriction and overall length of much less than half the length of anterior fontanelle within its section with defined lateral edges in Dipturus); neurocranium length about 40% of rostral shaft length (vs. neurocranium length much less than half rostral length in Dipturus). Figure 18 shows the radiograph of the R. lintea mature male head (ZMH 113180), and Table 2 provides cranial morphometrics measured from the radiograph of the latter mature male and on dissected cranium of a juvenile male (ZMH 101203).
Pelvic girdle (Fig. 19): ischiopubic bar massive, with nearly straight, only very weakly concave anterior contour; iliac regions moderately enlarged and with two iliac foramina on each side; prepelvic processes short, solid, conical, somewhat inclined outward and with bluntly rounded tip, their length only 1.6 times the median thickness of ischiopubic bar; posterior contour a shallow, broad trapezoid, and not a deeply concave arc as in adult males of many rajid species. Table 4 provides pelvis morphometrics measured from the radiograph. Maximum width of shoulder girdle, measured between outermost edges of metacondyles, of the mature male (ZMH 113180) is 203 mm, and the relation with maximum width of its pelvis is 1.5 times.
Scapulocoracoid (Fig. 20): element relatively short, subrectangular in lateral view, with maximum length 1.4 times the maximum height; height at not sharply marked rear corner (rc) 62% of maximum height; premesocondyle length with 1.1 times only a little longer than postmesocondyle length; postdorsal margin from rounded rear corner sloping slightly concavely to metacondyle; anterior bridge absent, broadly oval large anterior fenestra (af) oriented somewhat diagonally, only little higher than long and with 89% of its height above the horizontal line of maximum scapulocoracoid length; large postdorsal fenestra (pdf) subcircular and nearly as long as high; moderately large, horizontally oval postventral fenestra (pvf) 2.3 times longer than high, located level with postdorsal fenestra. Table 3 presents morphometrics of the dissected left element of an adolescent male of 894 mm TL (ZMH 25728).
element.
Skeletal meristics (from radiographs of mature male ZMH 113180): Vtr 36, Vprd 66, P-radials left/right 87/86, V-radials left/right 1+23/1+23. Stehmann (1970, Tables 3 to 5) stated for R. lintea: Vtr 34–35 (n = 6, Table 3), Vprd 68–72 (n = 6, Table 4) and P-radials 82–84 (n = 4, Table 5). Considering a moderate natural variation, the mature male falls well into these ranges.
ZMH 25728 juv. male 894 mm TL % max. length max. length, 57.0 mm 100.0
max. height 83.3
height at rc 51.8
pre-msc-length 51.8
post-msc-length 49.5
af-height 25.8
af-length 21.4
pdf-height 18.4
pdf-length 20.0
pvf-height 10.5
pvf-length 21.1
ZMH 113180 ZMUO J3139 mat. male juv. male 1239 mm TL 645 mm TL Maximum width, 139, 68 mm, resp. 100.0 100.0 Median transverse thickness 9.4 13.2
Prepelvic processes length 16.5 22.1
Iliac processes length 18.0 14.4
Depth posterior arc 15.1 13.3
description: Published as part of Stehmann, Matthias F. W., 2012, Complementary redescription of Raja lintea Fries, 1839 (Elasmobranchii, Rajidae) and its revised generic assignment, pp. 44-68 in Zootaxa 3331 on pages 46-64, DOI: 10.5281/zenodo.281245