Brent P. Thoma

A new species of Parapinnixa (Decapoda: Brachyura: Pinnotheridae) from Isla del Coco, Costa Rica

ABSTRACT A single ovigerous female of Parapinnixa cortesi, a new species, was collected from the calcareous tube of an unidentified serpulid polychaete on Isla del Coco, Costa Rica. The new species most closely resembles P. glasselli Garth, 1939, P. hendersoni Rathbun, 1918, and P. nitida (Lockington, 1876), but it can be distinguished from these and all other members of the genus by the morphology of the chelae and the proportions of the carapace.

Phylogeny of eriphioid crabs (Brachyura, Eriphioidea) inferred from molecular and morphological studies

The evolutionary relationships of the brachyuran crab superfamily Eriphioidea, commonly known as stone or rubble crabs, are examined. Analysis of three mitochondrial (12S, 16S and COI) and two nuclear loci (18S and Histone 3) was carried out for 51 taxa representing the Carpilioidea, Dairoidea, Eriphioidea, Goneplacoidea, Parthenopoidea, Pilumnoidea, Portunoidea, Pseudozioidea and Xanthoidea. Phylogenetic analyses of molecular data used three methods of inference that recovered similar topologies with minor differences. Maximum parsimony analysis of 20 morphological characters taken from first zoeas of 11 species yielded two equally parsimonious trees and generally supported the molecular analyses. None of the analyses recovered Eriphioidea as monophyletic, and each of the eriphioid families represented by two or more taxa was shown to be polyphyletic in both molecular and larval analyses. This study indicates that the present classification based on adult morphology is incongruent with phylogenetic relationships and that the diagnostic characters the result of convergence (particularly in feeding morphology) rather than shared ancestry.

A new genus for Chlorodiella longimana (H. Milne Edwards) supported by morphology and molecular data, with a preliminary phylogeny of the Chlorodiellinae (Crustacea:Decapoda:Xanthidae)

Abstract. Chlorodiella longimana is the only chlorodielline species presently known from the western Atlantic Ocean. Although C. longimana superficially resembles other species of the genus in general appearance of the carapace, morphological analyses revealed a suite of characters that separate it from all other known species of Chlorodiella – in particular, ambulatory legs having dactyli with a single tip and a basal antennal segment with a lateral flange that extends halfway into the orbital hiatus, excluding the antennal flagellum. In addition, a phylogenetic analysis of the Chlorodiellinae inferred from three mitochondrial markers (12S, 16S, COXI) and a nuclear marker (histone H3), confirms that C. longimana is genetically distinct from its congeners. A new genus, Ratha, is proposed to accommodate C. longimana. In addition, a phylogenetic analysis of six chlorodielline genera indicates that the subfamily is polyphyletic as presently defined.

Redescription of Pinnixa Arenicola Rathbun, 1922 (Decapoda: Brachyura: Pinnotheridae), With New Observations on Its Range and Host

Abstract Pinnixa arenicola is redescribed and illustrated on the basis of new collections and reexamined type material. Its occurrence in the burrows of Upogebia vasquezi Ngoc-Ho is reported, along with range extensions that include Florida, Puerto Rico, Aruba, and the Cayman Islands. New collections represent the first reports of P. arenicola since original discoveries in Curaçao and suggest a potentially wide distribution of the species in the tropical western Atlantic. Following publication of the unillustrated original description for the holotype male, females were also noted to occur in Curaçao, but illustrations with limited detail were provided by Rathbun for only the male holotype specimen. Prior to our work, no illustrations have depicted female morphology, unique male gonopods, or some pereopod features of potential value in defining phylogenetic relationships.

Redescription of Hexapanopeus lobipes and Its Reassignment to Milnepanopeus n. gen. (Decapoda: Brachyura: Panopeidae)

ABSTRACT Milnepanopeus n. gen. is proposed to accommodate the western Atlantic brachyuran crab, Hexapanopeus lobipes. Characters of the carapace, sternal groove, carpus of the ambulatory pereiopods, and male first gonopod define this presently monospecific genus. Recent molecular analyses support removal of H. lobipes from Hexapanopeus, and segregate this genus as a distinct lineage of Panopeidae Ortmann, 1893. The species is redescribed as Milnepanopeus lobipes, n. comb., on the basis of the holotype and supplementary material from deep banks in the Gulf of Mexico. Variations in morphology are addressed along with morphological comparisons to related genera of the family.