Arbaciella elegans Mortensen, 1910

Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), Zootaxa 4639 (1), pp. 1-231 : 171

Erroneous— Arbaciella elegans Mortensen, 1910

Reports for the Azores:

non Arbaciella elegans Mortensen 1910 — Marques 1983: 5 [misidentified juvenile of A. lixula ]; Pereira 1997: 334 [based on Marques 1983]; Haddad & Barreiros 2008: 9 [based on Marques 1983]; Micael & Costa 2010: 322 [based on Marques 1983]; Micael et al. 2012: 3. [based on Marques 1983].

Type locality: African west coast (Setté Cama, Gabon) .

See: Mortensen (1910, 1935); Koehler (1914b).

Occurrence: East Atlantic, Western tropical Africa from Cape Blanc to the Gulf of Guinea and Angola ( Koehler 1914b, Mortensen 1925).

Depth: shallow water ( Koehler 1914b).

Remarks: on erecting Arbaciella elegans, Mortensen (1910) observed the striking resemblance with young Arbacia species, particularly A. lixula and A. lixula africana , similar enough to cast doubts about the validity of this species (see also Mortensen 1935). Size at first sex maturity (presence of open gonopores), gross morphology, and colouration (which is strikingly colourful in comparison to that of juveniles of A. lixula ) were the main features used to differentiate this taxon. Revising Azorean material (Museu Bocage—Natural History Museum, Lot no. 20743, Ponta Delgada harbour, S„o Miguel Island) identified by Marques (1980) as Arbaciella elegans, Kroh et al. (2011) employed genetic tools and re-visited the ontogenic development of Arbacia lixula . They found that A. lixula juveniles (the identity of which was confirmed by DNA analysis) are identical in morphology to what previous authors (e.g., Gautier-Michaz 1955, 1958; Molinier & Picard 1956; Regis 1982) have considered as Arbaciella elegans in the Mediterranean and the northeastern Atlantic. Kroh et al. (2011) thus rejected the records of the Arbaciella elegans from these areas (including the Azores) as misidentifications of juveniles of A. lixula , reducing the distribution of Arbaciella elegans to its type area (tropical West African coasts). In addition, they cautioned that Arbaciella elegans as such may not be a distinct taxon and that it might turn out that all Arbaciella are juvenile Arbacia specimens (in the case of West Africa of A. lixula africana ) upon DNA-analysis of material from the type region.