Memoirs of the Museum of Victoria 54: 79-120 (1994) A PHYLOGENY OF THE FAMILIES OF THALASSINIDEA (CRUSTACEA: DECAPODA) WITH KEYS TO FAMILIES AND GENERA BY GARY C. B. POORE Department of Crustacea, Museum of Victoria, 71 Victoria Crescent, Abbotsford, Victoria 3067, Australia Abstract Poore, G.C.B., 1994. A phytogeny of the families of Thalassinidea (Crustacea: Decapo- da) with keys to families and genera. Memoirs of the Museum of Victoria 54: 79-120. The confused taxonomy of the Thalassinidea (73 genera recognised here) is briefly reviewed. States of 93 characters are discussed with reference to five outgroup genera of reptant decapods. The linea thalassinica is concluded to be homologous with the linea anomurica of Anomura. Its loss in Axioidea is thought secondarily derived. Burrowing behav­ iour in callianassoids is coincident with loss of the interaction between the posterior margin of the carapace and anterolateral lobes on abdominal somite 1, and with loss of abdominal pleura. Characters from gills, mouthparts and pereopods are discussed. Pereopodal spiniform setae are a unifying feature of some axioids. Auxiliary surfaces on the margins of pleopods of Callianidea and Michelea are not homologous. Setal-rows, once thought to unite several genera into the CalUanideidae are shown to be more widespread and this family, as previ­ ously conceived, to be polyphyletic. A computer-aided phylogenetic analysis of the families, represented by 22 genera, has confirmed the monophyly of the infraorder, based largely on the unique possession of a setose lower margin to pereopod 2, The Thalassinidea are divided into three superfamilies: Thalassinoidea and Callianassoidea, more closely related to each other than to Axioidea. The Thalassinoidea contains a single family and single genus, Thalassina. Callianassoidea are divided into six families: Laomediidae, Upogebiidae, CalUanideidae, Thomassiniidae, Ctenochelidae (paraphyletic), and Callianassidae. Axioidea contain four families; Calocari- didae, Axiidae, Strahlaxiidae fam. nov. and Micheleidae, The new classification differs from that of Borradaile (1903) only in the inclusion of many more taxa. The affinities between families suggested by Gurney (1938), de Saint Laurent (1973), Kensley and Heard (1991) and Sakai (1992a) are not supported. Diagnoses and keys are presented for the families and all the currently accepted genera, largely based on review of the literature and reference to museum collections. Contents Introduction 80 Methods 81 Outgroups 82 Taxa chosen 82 Character discussion 82 Results 88 The cladogram (ordered characters) 88 Character changes defining the clades and higher taxa 89 An alternate cladogram (unordered characters) 91 Ambivalent characters 91 A new classification of the Thalassinidea 92 Discussion 92 Thalassinidea 95 Axioidea 96 Axiidae 96 Calocarididae 98 Micheleidae 99 Tethisea gen. nov 99 Tethisea indica sp. nov 100 Strahlaxiidae fam. nov , 100 Author's corrections July 1994 On pp. 95 (twice), 96, 98 and 99 abdominal somite "3" should read abdominal somite "1". 80 GARY C. B. POORE Callianassoidea 101 Callianassidae 101 Callianideidae 103 Ctenochelidae 103 Laomediidae 103 Thomassiniidae 104 Upogebiidae 104 Thalassinoidea 105 Acknowledgements. 106 References 106 Introduction member of the Axiidae. Ortmann's taxonomic judgement was supported by Kensley (1989) but The decapod infraorder Thalassinidea is a was not followed by Sakai and de Saint Laurent group of families of reptant or "tailed decapods (1989). Kensley (1989) included in the Calo­ which recall the hermit-crabs in some respects carididae four genera previously included in the and the lobsters and crawfishes in others" (Bor- Axiidae. Scikai and de Saint Laurent (1989) sep­ radaile, 1903). A satisfactory diagnosis of the arated Coralaxius Kensley and Gore, 1981 into group has never been given in spite of the atten­ a new subfamily, Coralaxiinae. tion of numerous workers. While preparing a The Callianassidae and the smaller Callian­ contribution describing several new tha- lassinidean taxa it became clear that the Tha­ ideidae Kossmann, 1880 were first redefined in lassinidea had never been unambiguously a modern context by de Saint Laurent (1973) who defined and the relationships between all the fam­ erected a new subfamily of the former, ilies had not been thoroughly investigated. Thomassiniinae. This work was extended by Manning and Pelder (1991, 1992), Manning Several families have been assigned to the Tha­ (1992) and Rodrigues and Manning (1992) who lassinidea but the number, and the genera con­ erected four further callianassid subfamilies and tained therein, are somewhat contentious. Sev­ several new genera. Manning and Felder (1991) enty-three genera are recognised here but the implicitly raised Thomassininae to family rank. number of available names is larger. Three fam­ They added a new family Ctenochelidae (with ilies, each well defined but themselves not appar­ ently closely related, are: three subfamilies) for four atypical genera. Thalassinidae Dana, 1852 with two to four very Seven callianideid- and thomassiniid-like gen­ similar species in one genus (fig. la; Poore and era were grouped into the Callianideidae by Griffin, 1979; Dworschak, 1992; Sakai, 1992a). Kensley and Heard (1991). Sakai (1992a) added Laomediidae Borradaile, 1903 with 15 species another genus (here treated as a junior synonym in five diverse genera (fig. lb; Kensley and of Callianidea) and divided the family into four Heard, 1990); and subfamilies. Another is added in this work. Upogebiidae Borradaile, 1903 with over 100 Numerous new species are being described in species world-wide in seven quite similar genera work in progress. The genera of interest are: Cal­ (fig. Ic; Sakai, 1982; Ngoc-Ho, 1989; Williams lianidea Milne Edwards, 1837 (fig. 2a), Cros- and Ngoc-Ho, 1990; Sakai, 1993); niera Kensley and Heard, 1991, Marcusiaxius The monophyly of each of these three families Rodrigues and Carvalho, 1972 (fig. 3c), Meti- is not disputed and each can be defined by numer­ conaxius De Man, 1905, Michelea Kensley and ous autapomorphies. Heard, 1991 (fig. 3b), Mictaxius Kensley and The remaining genera have been assigned to Heard, 1991, Tethisea gen. nov. and Thomassinia at least two and as many as 14 family-level taxa de Saint Laurent, 1979a (fig. 2b). and their classification has been more unstable. The Thalassinidea have also included from The largest of these families are Axiidae Hux­ time to time the genera Enoplometopus Milne ley, 1879 (fig. 3a) and Callianassidae Dana, 1852 Edwards, 1862 and Hoplometopus Holthuis, (fig. 2c). Both have from time to time included 1983 in the Axiidae (Balss, 1957; Holthuis, 1983) some forms which could not be clearly assigned. but these are now removed to their own family One genus, Calocaris Bell, 1853, was moved to and superfamily (de Saint Laurent, 1988). its own family, Calocarididae Ortmann, 1891, The definition of the Thalassinidea and the but for most of this century has been treated as a relationships between families, subfamilies and A PHYLOGENY OF THE FAMILIES OF THALASSINIDEA 81 genera are now uncertain. There are competing shown by the modern axiids, upogebiids, definitions of Callianideidae, Thomassiniidae laomediids or thalassinids rather than by and their subfamilies. Examination of species of callianassids. In the axiids, for example, the Axiidae, Calocarididae, Ctenochelidae and Cal- cephalothorax is compact, little shorter than the lianassidae revealed that some of the characters abdomen, soUd, with a prominent rostrum from used to define the callianideid and thomassiniid which originate dorsolateral carinae running on groups are more widespread than hitherto appre­ to the carapace. The abdomen is firmly attached ciated and that neither the schemes of Kensley to the cephalothorax, has well developed pleura and Heard (1991) nor of Sakai (1992a) seem to on all somites, and is strongly reflexed. In addi­ reflect the phylogeny of the infraorder. tion, the second abdominal pleuron overlaps the It is the objective of this paper to attempt to first anteriorly and the two abdominal somites define the Thalassinidea and to present a new articulate by means of a lateral condyle (cf. hypothesis explaining family relationships. The Burkenroad, 1981: 259-260). Thepleopods 2-5 work does not resolve generic definitions or rela­ are similar and sexually unspecialised, and the tionships in the Axiidae and Calocarididae [dealt pereopods 2-4 are typically cylindrical and lin­ with by Sakai and de SaintLaurent (1989), Kens- ear rather than flattened for digging in soft sedi­ ley (1989, work in progress)], and Callianassi- ments. dae and Ctenochelidae [dealt with by Manning As far as is known axiids live in short burrows and Felder (1991, 1992), Manning (1992) and in hard or soft sediment, in crevices between Rodrigues and Manning (1992)] although many rocks, or in cavities in sponges or corals. Kens- taxa in these families have been examined in the ley and Simmons (1988) described the straight course of this study. This need arose from the 150-mm-long burrows of their new spsci&sAxio- realisation that these families are not as homo­ rygma nethertoni. Pemberton et al. (1976) report­ geneous as current usage suggests. ed that Axius serratus builds burrows up to 3 A new classification and diagnoses of the metres deep. Calocaris macandrae (Calocaridi­ superfamilies and families reflecting these rela­ dae) has also been reported to construct burrows tionships are offered. Keys, based mostly