Infraorder ANOMURA H. Milne Edwards, 1832

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Infraorder ANOMURA H. Milne Edwards, 1832

Compiler and date details

April 2012 - Peter Davie, Queensland Museum

Anomoures H. Milne Edwards, 1832.

Taxonomic Decision for Synonymy

Poore, G.C.B. 2016. The Names of the Higher Taxa of Crustacea Decapoda. Journal of Crustacean Biology 36(2): 248–255 [250]

Introduction

The infraorder Anomura now is considered to include 19 families arranged in seven superfamilies (see McLaughlin et al. 2010; Ahyong et al. 2011): Lomisoidea (hairy stone-crabs—Lomisidae); Lithodoidea (stone or king crabs, Hapalogastridae, Lithodidae); Paguroidea (hermit-crabs— Coenobitidae, Diogenidae, Paguridae, Parapaguridae, Pylochelidae, Pylojacquesidae); Aegloidea (Aeglidae); Galatheoidea (squat lobsters, porcellain-crabs and allies— Galatheidae, Munididae, Munidopsidae Porcellanidae); Chirostyloidea (Chirostylidae, Eumunididae); and Hippoidea (mole-crabs—Albuneidae, Blepharipodidae, Hippidae). Only the Aeglidae, Hapalogastridae and Blepharipodidae are not represented in Australian waters. Borradaile (1903) included the Thalassinoidea within the Anomura, and this view held sway for many years, even into recent literature (Glaessner 1969; McLaughlin 1980; Williams 1984). Burkenroad (1963) excluded thalassinids, a move supported by de Saint Laurent (1979), and having wide acceptance since Bowman & Abele's (1982) 'Classification of Recent Crustacea'.

Within the Paguroidea the traditional concept of evolution held that the lithodid crab-like body form evolved from a typical shell-dwelling hermit crab—a view given modern credence by Cunningham et al. (1992) on the basis of DNA data. However, in two recent papers, McLaughlin & Lemaitre (1997, 2000) have presented convincing evidence from adult and larval morphology that points to the reverse having occurred, the hermit-crabs having arisen from a lithodid-like ancestor through calcium loss, habitat change, and consequential morphological adaptations.

Williamson (1992) and Spears et al. (1992) posited the controversial view that the Dromioidea brachyurans are actually anomurans, although this was disputed by Scholtz & Richter (1995), and is not accepted here.

Often the alternative name 'Anomala' has been used for this group. McLaughlin & Holthuis (1985) discussed thoroughly the nomenclatural history of both names, and recommended use of Anomura on the basis of widest usage, and in the interests of stability of nomenclature.

Diagnosis

Carapace variable in shape; not fused to epistome. Eyes stalked, compound; generally well developed. Antennules with peduncle 3-segmented; flagella usually paired. Antennal peduncles sometimes with 5, possibly 6, or fewer segments; exopod usually reduced to acicle; flagellum variable in length. Mandibles with or without palp; molar and incisor processes usually not distinct. Maxillulae with endopodal palp. Maxillae biramous; usually with bilobed endites. Maxillipeds with flagella usually present; sometimes absent from first; often with crista dentata; usually not operculate. First pereiopod usually chelate, second sometimes chelate; fourth and fifth usually chelate or subchelate, one or both frequently reduced. Abdomen with pleopods rarely well developed; often reduced or present only on one side; both sexes sometimes with copulatory structures; uropods often reduced or modified, occasionally absent; telson occasionally reduced or absent; sometimes together with uropods forming tailfan. Segmentation: head with 5 + 3 thoracic (maxillipeds); thorax with 5; abdomen with 6, excluding telson, although segmentation frequently obscured. Sexes separate; gonopores on coxae of third pereiopods of female, on fifth of male; first and/or second pleopods often modified as gonopods in both sexes; female sometimes with abdominal brood pouch; male sometimes with sexual tube(s). (After McLaughlin 1980).