Revision of the West African species of Scyllarus Fabricius, 1775 (Decapoda: Achelata: Scyllaridae), with the description of three phyllosoma stages of S. caparti Holthuis, 1952 and an updated identification key

West African species of ScyllarusFabricius, 1775 (Achelata, Scyllaridae) are poorly known, mostly due to the difficulties of sampling Eastern Atlantic tropical waters. Recent expeditions carried out by the Universidad de Cádiz and the Instituto Español de Oceanografía collected phyllosoma larvae from Cape Verde Islands (CVI) and fresh Scyllarus adults from continental West Africa. Larval stages VII, IX, and X (final stage) of S. capartiHolthuis, 1952 are analyzed using DNA barcoding methods and described for the first time. A comprehensive identification key is provided, summarizing our current knowledge on the phyllosomas of Scyllarus. Together with a revision of museum collections, the new molecular and morphological data obtained here supports the polyphyletic origin of AcantharctusHolthuis, 2002. The West African A. posteli (Forest, 1963) is found to belong to Scyllarus and it is closest to another species from Atlantic shallow waters (i.e. S. paradoxusMiers 1881), whereas the Pacific Ocean A. delfini (Bouvier, 1909) would belong to CrenarctusHolthuis, 2002.

Morphological differences between phyllosoma larvae from the western–central and eastern Pacific populations of the pronghorn spiny lobster Panulirus penicillatus

The pronghorn spiny lobster Panulirus penicillatus is known to have the widest distribution among palinurid lobster species, occurring in tropical and sub-tropical areas of the Indo-Pacific Ocean. In the Pacific Ocean, mitochondrial DNA analyses have revealed that the western–central and eastern populations are genetically isolated. We performed morphological investigations on mid- to late-stage phyllosoma larvae collected in these two areas. The larvae of the western–central population had a significantly narrower cephalic shield, shorter abdomen, and longer eyestalk than those of the eastern population. Additionally, for larvae larger than about 25-mm body length, the widest position of the cephalic shield in the western–central population was located closer to the middle of the median line of the cephalic shield than that in the eastern population. The ratio of width to length of cephalic shield and the ratio of cephalic shield width to thorax width are key traits for distinguishing between the larvae of the two populations.