Pylochelidae Spence Bate 1888

Family Pylochelidae Spence Bate, 1888

Remarks. The subfamily and family level classification of the Pylochelidae has been subject to debate. In his monumental revision of the family, Forest (1987a) recognized six subfamilies within the Pylochelidae, viz., Pylochelinae, Pomatochelinae, Parapylochelinae, Cancellochelinae, Trizochelinae and Mixtopagurinae. On the basis of phylogenetic relationship inferred from morphological data (Lemaitre et al. 2009), McLaughlin & Lemaitre (2009) proposed a new classification of the Pylochelidae, recognizing three subfamilies (Pylochelinae, Pomatochelinae and Trizochelinae) with Parapylochelinae and Cancellochellinae relegated to tribes under Trizochelinae (viz., Trizochelini, Cancellochelini and Parapylochelini). Subsequently, molecular phylogenetic analysis using five nuclear protein-coding genes by Tsang et al. (2011) indicated that Pylochelidae is polyphyletic, consisting of two, major, distantly related clades (Pylocheles + Xylocheles is the sister group of Galatheidae s.l. + Porcellanidae; Trizocheles is the sister group of Parapaguridae + Lomisidae + Aeglidae + Kiwaidae + Chirostylidae), though no formal change in classification was proposed. On the other hand, the Bayesian analysis from the combined molecular + morphological dataset performed by Bracken-Grissom et al. (2013) recovered the monophyletic Pylochelidae. Recently Fraaije et al. (2012) proposed a new family Parapylochelidae to accommodate Parapylocheles and their new fossil genus Mesoparapylocheles Fraaije, Klompmaker & Artal, 2012. In this present study, we follow McLaughlin & Lemaitre’s (2009) classification, because it is based on extensive morphological analysis covering all species known at the time. Fraaije et al. (2012) emphasized the uniqueness of the Parapylochelidae, but unique characters do not contribute to finding the sister group to Parapylocheles. In addition, the erection of the new family under their own authorship (Fraaje et al. 2012; also see Fraaje 2014) is not justified according to the Article 36 of ICZN (1999). The authorship of Parapylochelidae should be attributed to Forest (1987a) who formally proposed a subfamily rank (i.e., Parapylochelinae) for this group. In fact, Fraaje et al. (2014) corrected back the authorship of the Parapylochelidae to Forest (1987a), though they did comment on the change.