Chimaera opalescens n. sp., a new chimaeroid (Chondrichthyes: Holocephali) from the north-eastern Atlantic Ocean

Abstract

A new species of chimaeroid, Chimaera opalescens n. sp., was described from 31 type specimens caught in the north-eastern Atlantic Ocean at 950-1400 m depth. This species differed from all its congeners by the combination of the following characters: body uniformly pale brown to bronze, iridescent on fresh specimens; unpaired fins brown to purple, uniformly coloured or with pale or whitish edges; iris black; claspers tripartite and divided for a third of their length, not extending beyond the pelvic fins in adults; dorsal spine equal to or shorter than first dorsal fin; ventral caudal lobe equal to or deeper than dorsal caudal lobe. Comparison of DNA sequences of the CO1 gene with those of related species supported C. opalescens n. sp. as a distinct species. Specimens of C. opalescens n. sp. were previously misidentified as Chimaera monstrosa, a species sharing a similar geographical distribution. Chimaera opalescens n. sp. lives in deeper water and is a larger-bodied species than C. monstrosa. The two species were newly exploited by deep-sea fisheries and confused under a single landing name.

First records of Chimaera opalescens (Holocephali: Chimaeriformes: Chimaeridae) from Madeira and north-west African Coast

“…The genus Chimaera includes 16 species (Weigmann 2016) two of which, Chimaera monstrosa Linnaeus, 1758 and Chimaera opalescens Luchetti, Iglésias et Sellos, 2011, are known from the northeast Atlantic Ocean (Luchetti et al 2011, Weigmann 2016, Eschmeyer et al 2017.…”

“…Chimaera opalescens can be distinguished from its congener by the following combination of characters: body colour beige to tan in adults and bronzy in juveniles, unpaired fins brown to purple, uniformly coloured or with pale or whitish edges, iris black, claspers tripartite divided for one third of their length, not extending beyond pelvic fins in adults, dorsal spine equal or shorter than first dorsal fin, ventral caudal lobe equal or deeper than dorsal caudal lobe and pectoral fins just reaching origin of pelvic-fin when laid backwards, in freshly caught adult specimens (Luchetti et al 2011). Despite the distinct morphological differences, mainly in the claspers, dorsal spine and fins, it is still commonly misidentified as Chimaera monstrosa (see Luchetti et al 2011, Vieira andCunha 2014).…”

“…Its geographic distribution extends from Greenland to the western slope of the British Isles and France, at latitudes between 48° and 59°N (Møller et al 2004, Luchetti et al 2011, Holt et al 2013, the Galicia Bank (Bañon et al 2016), and south to the Gorringe Bank (36º37.95′N, 11º02.25′W) (Vieira and Cunha 2014).…”

“…All specimens were measured following Didier and Séret (2002) and Luchetti et al (2011). Abbreviations: TL = total length, PCL = pre-caudal length, PD2 = pre-second dorsal fin length, PD1 = pre-first dorsal fin length, HDL = head length, DSA = dorsal spine length along anterior margin, D1B = first dorsal fin base length, IDS = inter-dorsal space, D2B = second dorsal fin base length, CFI = caudal-filament length, P1A = pectoral-fin anterior margin length, P2A = pelvic-fin anterior margin length, EYL = eye length, EYH = height, CLT = total length of clasper.…”

Review of the Diversity, Ecology, and Conservation of Elasmobranchs in the Azores Region, Mid-North Atlantic

“…Chimaera opalescens * (Luchetti et al, 2011) A recently described Holocephalan that is known only since 2011 (Luchetti et al, 2011). It is suspected that records of Chimaera monstrosa from the region might be misidentified C. opalescens (Diana Catarino IMAR/Azores, pers.…”