Elasmobranchii (sharks and rays) >
Rajiformes (Skates and rays) >
Arhynchobatidae (Softnose skates)
Etymology: heuresa: 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 (Ref. 89011).
More on authors: Last & Séret.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; bathydemersal; depth range 870 - 1350 m (Ref. 89011). Deep-water; 32°S - 36°S, 166°E - 170°E
Tasman Sea: 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 (Ref. 89011).
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 35.5 cm WD male/unsexed; (Ref. 89011); 36.4 cm WD (female)
Short description
Identification keys | Morphology | Morphometrics
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 (Ref. 89011).
Life cycle and mating behavior
Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae
Last, P.R. and B. Séret, 2012. Two new softnose skates of the genus Brochiraja (Rajoidei: Arhynchobatidae) from the deepwater slopes and banks of the Norfolk Ridge (South-West Pacific). Zootaxa 3155:47-64. (Ref. 89011)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
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Internet sources
Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5039 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00550 (0.00273 - 0.01106), b=3.10 (2.93 - 3.27), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.8 ±0.7 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref.
59153): Moderate vulnerability (42 of 100).
