Rajella Stehmann 1970, subgen. nov.
Creators: name: Weigmann, Simon
name: Stehmann, Matthias F. W.
name: Thiel, Ralf
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Rajiformes
Rajidae
Rajella

description: Genus Rajella Stehmann, 1970
Translation of the original diagnosis by Stehmann (1970). I. Genus Raja Linnaeus, 1758
5. subgenus Rajella subgen. nov.
Type species: Raja fyllae Lütken, 1888.
Diagnosis: a subgenus of the genus Raja Linnaeus, 1758 with the following characters: Clasper short and overall evenly slender; external pseudosiphon usually present; components slit, cleft, rhipidion, shield, sentinel and spike present; clasper skeleton with 4 dT-, 2 aT-cartilages and vT. Length of rostrum much shorter than that of neurocranium, nasal capsules remarkably large; regio orbito temporalis deeply concave. A small species with roundish disc; snout blunt, extremely short, snout angle 115°–156°. Anterior margin of disc strongly indented at level of spiracles in adult males. Tail length distinctly larger than disc length, distance between mid-vent and tail tip 1.3–1.6 times the distance between mid-vent and snout tip. Disc and tail dorsally set with spinules, thornlets and thorns; 1–3 pre-, 1–3 postorbital thorns, often an orbital ring of 5–9 thorns each side; 1–5 nuchal, 1–2 suprascapular, 1–3 scapular thorns, commonly a large triangle of thorns over these three regions; a median row of small thorns on back of trunk and tail in juveniles, along with several rows of irregularly set larger thorns from shoulder region to partly level of second dorsal fin; interdorsal thorns usually lacking; median row of thorns in semiadult and adult specimens with distinctly smaller thorns than those in parallel rows, or median thorns totally absent. Ventral side smooth. Dorsal ground color dark. Disc with pattern of irregular spots and dots. Ventral side predominantly white. Vtr: 25–29; Vprd: 64–77; pectoral radials: 63–68. Species in NE-Atlantic: fyllae. Presumably affiliated or closely related species outside the NE-Atlantic: lentiginosa, ocellata (W-Atlantic). Distribution: latitudinally amphi-North Atlantic.
Revised generic diagnosis of Rajella Stehmann, 1970 (based on 18 species known to date, including the new species described herein). A rajid skate genus whose members can be found almost worldwide on shelves and slopes in temperate and tropical latitudes. Species are small (total length (TL) to about 60 cm) to moderately large (TL up to about 130 cm). Disc shape roundish with short, obtusely angled snout to subrhombic with moderately long, pointed snout. Tail solid and gradually tapering to tip. Tail distinctly longer than distance from snout tip to mid-vent in small species with roundish discs, but equal to or shorter in larger species with subrhombic discs. Bases of dorsal fins mostly confluent, otherwise interdorsal space very short. Postdorsal tail section very short. Sensory and mucus pores not black-marked. Upper sides of disc and tail usually largely covered with dermal denticles. Most species with more or less pronounced thorn pattern including thorns on snout, half rings on orbital rims, a triangular patch on nape-shoulder region, a median row from trunk to first dorsal fin (reduced with advancing age in some species), and usually at least two parallel rows of large thorns. Some small species with additional thorns scattered on pectoral fins, while in some larger species the thorn patterns on snout, orbital rims, and nape-shoulder region are reduced and parallel thorn rows are absent or shorter and consisting of smaller thorns. Interdorsal thorns present or absent. Dorsal and ventral ground color varies, partly depending on growth stage, from dark to plain whitish, may be uniformly colored or with different patterning, few species with plain dark ventral and lighter dorsal disc. Claspers of adult males rather short, hardly reaching half-length of tail, slender to more massive, with terminal region usually somewhat widened. External pseudosiphon lacking; occasionally a pseudosiphon-like groove present in dorsal semi-terminal dilatator muscle, but outer border of groove not supported by edge of dorsal terminal 1 cartilage. Components cleft, rhipidion, sentinel, shield, spike, and terminal bridge present; partially also dike, eperon, flag, pent, sentina, slit, and spur present. Contrary to the generally similar genus Leucoraja, the components promontory and roll are lacking. Additionally to axial and dorsal and ventral marginal cartilages, terminal clasper skeleton with 2–3 accessory terminal cartilages, 4–5 dorsal terminals, a terminal bridge, and a ventral terminal; dorsal terminal 2 without long, solid distal process. However, clasper features of some species are still unknown. Length of rostrum variable, cranial orbit contour from deeply concave to shallower trapezoid-shaped. Scapulocoracoid with one anterior fenestra without anterior bridge, one large postdorsal, and one large postventral fenestra. Pelvic girdle straight, posterior contour weakly concave, prepelvic processes massive and short. Upper jaw tooth rows: 26–70; trunk vertebrae (Vtr): 23–36; predorsal tail vertebrae (Vprd): 52–77; pectoral radials: 55–87. Due to the large interspecific variation in external characters, clasper features presently appear to be the most reliable generic characters. A list of all 18 valid species of Rajella can be found under Discussion.
description: Published as part of Weigmann, Simon, Stehmann, Matthias F. W. & Thiel, Ralf, 2014, Rajella paucispinosa n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the western Indian Ocean off South Mozambique, and a revised generic diagnosis, pp. 359-387 in Zootaxa 3847 (3) on pages 360-361, DOI: 10.11646/zootaxa.3847.3.3, http://zenodo.org/record/251089