Indopinnixa Manning & Morton, 1987

Lasley Jr, Robert M., Anker, Arthur & Naruse, Tohru, 2024, Two new species and a new record of infaunal crabs (Decapoda: Brachyura: Pinnotheridae and Varunidae) from Oman and Saudi Arabia, Zootaxa 5476 (1), pp. 207-229 : 208

Indopinnixa Manning & Morton, 1987

Indopinnixa Manning & Morton, 1987: 543 .

Type species. Indopinnixa sipunculana Manning & Morton, 1987 , by original designation.

Remarks. Manning & Morton (1987) erected the genus Indopinnixa to accommodate a new species from Hong Kong, Indopinnixa sipunculana Manning & Morton, 1987 . They differentiated Indopinnixa from Pinnixa White, 1846 based on the fusion of the male pleonites, with Indopinnixa having pleonites 5–6 fused (vs. not fused in Pinnixa ). However, Naruse & Maenosono (2012: table 1) reviewed Indopinnixa and noted varying degrees of fusion of pleonites, such as pleonites 3–6 functionally fused with sutures visible, pleonites 5–6 fused, etc. They also noted that several members of Pinnixa have varying degrees of pleonite fusion (Naruse & Maenosono 2017: table 1), thus contradicting Manning & Morton’s (1987) separation of the two genera based on this character. In fact, several authors stated the need to revise Indopinnixa and clarify its relationships with Pinnixa (e.g., Rahayu & Ng 2010; Ng 2014; Komai et al. 2022).

A recent systematic study of Pinnixa and several related genera, which included a molecular phylogeny based on three mitochondrial and nuclear genes ( Palacios Theil & Felder 2020), indicated that Indopinnixa is sister to a clade containing species in the genera Pinnixa , Glassella Campos & Wicksten, 1997 , and Laminapinnixa McDermott, 2014 . All species in this sister clade were assigned to Glassella , resulting in the synonymy of Laminapinnixa with Glassella . The molecular dataset of Palacios Theil & Felder (2020) only contained two species of Indopinnixa ( I. kumejima Naruse & Maenosono, 2012 and I. moosai Rahayu & Ng, 2010 ), and none of the six species of Pinnixa from the western Pacific ( P. balanoglossana Sakai, 1934 ; P. banzu Komai, Nishi, & Taru, 2009 ; P. lata Komatsu & Takeda, 2009 ; P. penultipedalis Stimpson, 1858 ; P. rathbuni Sakai, 1934 ; P. tumida Stimpson, 1858 ). With a redescription of Pinnixa haematosticta Sakai, 1934 and its transfer to the genus Indopinnixa, Komai et al. (2022) reviewed the morphology of Indopinnixa and Glassella , as presently defined, and concluded that the two genera can be separated from each other by the absence ( Indopinnixa ) or presence ( Glassella ) of a gonopodal plate on the inner side of the male pleon and the configuration of G1. The two genera were further differentiated by the length/height proportion of the P5 dactylus by Poore & Ahyong (2023). Therefore, in the present study, Indopinnixa is treated sensu Komai et al. (2022); however, Indopinnixa , Glassella and the western Pacific species presently assigned to Pinnixa clearly need more taxonomic efforts.