Thursday, June 25, 2020

[Cnidaria • 2020] There are Three Species of Chrysaora (Scyphozoa: Discomedusae) in the Benguela Upwelling Ecosystem, not Two; Chrysaora fulgida, C. africana & C. agulhensis


 Chrysaora agulhensis
Ras, Neethling, Engelbrecht, Morandini, Bayha, Skrypzeck & Gibbons, 2020


Abstract
Chrysaora (Pèron & Lesueur 1810) is the most diverse genus within Discomedusae, and 15 valid species are currently recognised, with many others not formally described. Since Chrysaora fulgida (Reynaud 1830) was first recognised as occurring off the south west (SW) coast off South Africa, the species has been variously synonymised with Chrysaora hysoscella (Linnaeus 1767) and Chrysaora africana (Vanhöffen 1902). Using DNA evidence alongside multivariate tools to analyse quantitative morphometric and meristic data, as well as information from the cnidome, we unambiguously separate C. fulgida from C. hysoscella; we resurrect C. africana as a valid species and recognise a new species, Chrysaora agulhensis sp. nov. Full descriptions of C. fulgida, C. africana and C. agulhensis sp. nov. are provided. The species have different geographical patterns of distribution around the region, with restricted areas of overlap: C. agulhensis sp. nov. is found along the southern coast of South Africa and over the Agulhas Bank, C. fulgida extends from Cape Point in South Africa to southern Angola, and C. africana can be found from southern Namibia northwards to the Gulf of Guinea. The species can be readily separated in the field by a combination of tentacle/lappet number and shape, colour patterns and the form of the oral arms.

Keywords: Coelenterata, Agulhas Bank, Benguela upwelling region, Namibia, New species, Pelagiidae, Scyphozoa, Taxonomy

SYSTEMATICS
Subclass DISCOMEDUSAE Haeckel, 1880

Order SEMAEOSTOMEAE L. Agassiz, 1862
FAMILY Pelagiidae Gegenbaur, 1856

GENUS Chrysaora Péron and Lesueur, 1810

 Chrysaora agulhensis sp. nov. collected at Whale Rock during November 2012
side-view of a larger specimen in situ displaying deep purple colouration of the central apex, long trailing oral arms and ribbon-like tentacles. 

 Chrysaora agulhensis sp. nov.

 Diagnosis. Chrysaora of medium size; 32 rounded marginal lappets, four per octant; no more than 24 persistent tentacles; tentacles laterally flattened with pronounced bases, and ribbon-like; oral arms longer than bell, folded spirally at base; characteristic star shape pattern on exumbrella surface always visible, created by the radial pattern of deep maroon/purple triangles; white spots scattered across the surface of the exumbrella; mouth becomes substantially larger as organism grows. Lappets with network of gastrovascular canals. Oral arms spirally arranged basally.

Distribution. Range stretches from Table Bay along the west coast of South Africa towards Port Elizabeth along the south east coast of South Africa (Agulhas Bank): endemic.

Etymology. “agulhensis” referring to its distribution across the Agulhas Bank along the South coast of South Africa.

    


V. Ras, S. Neethling, A. Engelbrecht, A.C. Morandini, K.M. Bayha, H. Skrypzeck and M.J. Gibbons. 2020. There are Three Species of Chrysaora (Scyphozoa: Discomedusae) in the Benguela Upwelling Ecosystem, not Two. Zootaxa. 4778(3); 401-438. DOI: 10.11646/zootaxa.4778.3.1

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