RHYNCHOCINETIDAE SENSU YALDWYN (1960) IS NOT A

Baeza, J. Antonio, Bauer, Raymond T., Okuno, Junji & Thiel, Martin, 2014, Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny, Zoological Journal of the Linnean Society 172 (2), pp. 426-450 : 444

THE FAMILY RHYNCHOCINETIDAE SENSU YALDWYN (1960) IS NOT A NATURAL ENTITY

Yaldwyn (1960) proposed that the species of Rhynchocinetes , Lipkius , and Eugonatonotus comprised the family Rhynchocinetidae . Bowman & Abele (1982) then established the superfamily Rhynchocinetoidea , comprising three families, Bresiliidae Calman, 1896 , Eugonatonotidae , and Rhynchocinetidae . These authors provided no explanation for the estab- lishment of the Rhynchocinetoidea and their proposal has been rejected by most taxonomists in recent decades. Later, Christoffersen (1990) transferred the genus Lipkius to the family Nematocarcinidae (see above). Most recently, Holthuis (1995) and Okuno (1997) suggested that only the species of Rhynchocinetes (and Cinetorhynchus ) should be placed in the Rhynchocinetidae , separately from the genus Lipkius . This latter genus was included, amongst others, in the family Nematocarcinidae . In turn, the genus Eugonatonotus was placed in its own family, the Eugonatonotidae . Traits that define the Rhynchocinetidae sensu Holthuis (1995) and Okuno (1997) include, amongst others, a rostrum that is usually incompletely fused with the remainder of the carapace that has two or three teeth on the median carina, no supraorbital spine, and one spine at the posterolateral margin of the fifth abdominal somite (Okuno, 1997).

The various analyses used in this study do not support either Yaldwyn’s (1960) grouping of the genera Rhynchocinetes , Lipkius , and Eugonatonotus in a single clade, or monophyly of his Rhynchocinetidae . Notably, the genera Rhynchocinetes and Cinetorhynchus clustered together, forming a single, well-supported monophyletic clade. Altogether, the above information implies that the Rhynchocinetidae represent a natural clade, as suggested by Okuno (1997). Our results are also in line with those of Li et al. (2011), who found no support for the monophyly of Rhynchocinetidae sensu Yaldwyn (1960) using five different nuclear gene fragments but a smaller number of representatives from this family than in the present study.

THE GENERA RHYNCHOCINETES AND CINETORHYNCHUS ARE NATURAL ENTITIES: THE