Leucosiidae, Samouelle, 1819

GUINOT, DANIÈLE, TAVARES, MARCOS & CASTRO, PETER, 2013, Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea, Decapoda, Brachyura), with new nomina for higher-ranked podotreme taxa, Zootaxa 3665 (1), pp. 1-414 : 127

Families Leucosiidae and Iphiculidae

The male gonopore is coxal, and the penis varies from moderately long to long. The emergence of the penis, which perforates the extremity of the coxo-sternal condyle (see Modalities of penis protection: Condylar protection), is a synapomorphy of Leucosioidea ( Leucosiidae and Iphiculidae Alcock, 1896 ). The condyle, generally slightly elongated, is encircled between extensions of sternites 7 and 8 and enters the sternal gynglyme with a ventral articular point that is not dorsally visible ( Fig. 30 ). The Leucosioidea shows a transformation series from coxal to coxo-sternal condition, with many intermediate stages that are difficult to categorise. The coxal gonopore is variously enclosed by extensions of sternites 7 and 8 ( Iphiculus Adams & White, 1849 , Pariphiculus Alcock, 1896 , Lithadia Bell, 1855 ) or surrounded by the expanded sternite 7 and a weak extension of sternite 8 ( Fig. 30A, B, D, E : Ebalia Leach, 1817 , Ilia Leach, 1817 , Myra Leach, 1817 , Pseudomyra Capart, 1951 ). Ultimately, the gonopore is completely covered by the entirely joined episternites 7 and 8 ( Fig. 30C, F ; Cryptocnemus Stimpson, 1858 , Euclosia Galil, 2003 , Leucosia Weber, 1795 , Philyra Leach, 1817 ). The configuration of the genital area has unfortunately not been studied in the different leucosioid genera. Additional protection is provided to the penis when the junction of sternites 7 and 8 over the coxa and its condyle is complete (see Modalities of penis protection: Condylar protection; Monophyletic Heterotremata: Superfamily Leucosioidea ).

Figures

FIGURE 30. Coxal to coxo-sternal condition in Leucosiidae, penis enclosed inside P5 coxo-sternal condyle (abdomen removed). A, Ebalia nux A. Milne-Edwards, 1883, male, Bay of Biscay (MNHN-B20067); B, Pseudomyra mbizi Capart, 1951, male 25.0 × 20.0 mm, Congo (R.O.C.) (MNHN-B17570); C, Philyra pisum De Haan, 1841, male 21.0 × 20.5 mm, Japan (MNHN-B16982). D–F, schematic representation of A–C, portion of P5 coxa covered by episternites 7 and 8 (dotted line in C and F). a8, p8, anterior and posterior expansions of sternite 8; c, P5 coxo-sternal condyle; cx4, cx5, P4, P5 coxae; e7, e8, episternites 7, 8; g, gonopore; 7, 8, thoracic sternites 7, 8; 6/7, 7/8, thoracic sternal sutures 6/7, 7/8.