Metapseudidae Lang, 1970

Stępień, Anna & Błażewicz-Paszkowycz, Magdalena, 2013, Four new species and two new genera of Metapseudidae (Crustacea: Tanaidacea: Apseudomorpha) from Australian coral reefs, Zootaxa 3717 (4), pp. 559-592 : 560-561

Family Metapseudidae Lang, 1970

Remarks. The Metapseudidae , currently represented by 86 species classified in four subfamilies and 20 genera (Anderson 2013; Appeltans et al. 2013), is one of the most diverse families associated with coral reefs. From 79 species of tanaidaceans recorded globally from coral reefs, 28 are members of the Metapseudidae .

The family was established by Lang (1970) to accommodate four genera: Apseudomorpha Miller, 1940 , Cyclopoapseudes Menzies, 1953 , Metapseudes Stephensen, 1927 and Synapseudes Miller 1940 , which in those days included around 21 species. Two years later, Gutu (1972) defined two subfamilies, the Metapseudinae Lang 1970 and the Synapseudinae Gutu, 1972 , based on the reduction (= fusion) of the pleonites with the pleotelson. Later on the family was supplemented by two other subfamilies: the Chondropodinae (Gutu 2008) and the Msangiinae (Gutu, 2006) .

Although the Metapseudidae currently includes four times as many species as when Lang (1970) established the family, its definition has never been updated. Most of the characters pinpointed by Lang are vague and allow only to distinguish the metapseudids from the members of the Kalliapseudidae (by having the dactylus not modified, without sensory setae) or some apseudids (by the character of the seta on the endite of the maxilliped). The metapseudids can be distinguished from the Sphyrapodidae by presence in the latter of six fully developed pereonites; from the Parapseudidae and most Apseudidae (except Frankapseudes and Atlantapseudes ) by a reduced antennal squama; from the Whiteleggiidae by the lateral attachment or absence of pleopods, from the Sphaeromapseudidae and the Tanzanapseudidae by their elongated body; and from the Pagurapseudidae and the Numbakullidae by having the first pair of pereopods fossorial.

Undoubtedly the Metapseudidae requires profound revision and new definition. The same is also true for some of metapseudid genera (e.g. Synapseudes ), as well as for the subfamilies. It is very probable that the Msangiinae Gutu, 2006 or the Chondropodinae Gutu, 2008 might not be closely-related to the Synapseudinae Gutu, 1972 or the Metapseudinae Lang, 1970 , and that they might need to be raised to family rank. A debate on the phyletic relationship within the Metapseudidae is beyond the scope of this paper, however a phylogenetical analysis based on morphological characters is demonstrating that all metapseudids, tanzanapseudids, pagurapseudids, whiteleggiids and sphaeromapseudids may constitute a monophyletic clade (studies in progress).

Metapseudids are tropical and temperate crustaceans, with the most northerly records of the family coming from the English Channel in the Atlantic (Guţu 1989a) and the East China Sea in the Pacific (Larsen & Shimomura 2006); in the southern hemisphere their most southern records are at Tierra del Fuego (Sieg 1986a), waters off Southern Africa (Barnard 1914), New Zealand (Chilton 1882; Gardiner 1973) and SE Australia (Błażewicz- Paszkowycz & Bamber 2012). The Metapsudidae are generally shallow water crustaceans, which rarely occur below 100 m (Gardiner 1973; Gutu 1989b). They are most often associated with coral rubble, but also with sponges (Shiino, 1951), algae (Menzies 1953), turf of Bryozoa (Menzies 1953, Bamber 2008) or occasionally with sand, mud or shell-sand (e.g. Gutu, 2006).

Subfamily Chondropodinae Gu t u, 2008

Definition (amended after Gutu 2008): Body dorsoventrally flattened. Pleon with five short pleonites; pleotelson short with small acute lateral process. Antennule peduncle with at least one apophysis on inner margin of first article (except Bamberus ); at least outer flagellum long, multiarticulated. Antenna second article long, with apophyses on inner margin (except Vestigiramus ); squama small. Maxilliped palp article 3 longer than broad. Pereopod 1 fossorial; exopodite terminal article with usually more than four setae; basis thick with plumose setae on dorsal margin and usually with spiniform denticles (except Bamberus ). Pereopods 2 to 6 slender, walking type; pereopods 3 to 6 with propodus longer than carpus, and usually subequal merus, slightly curved. Pleopods present, biramous, in five pairs. Uropod with multiarticulated rami. Dimorphism: usually well-developed, male with dimorphic chelipeds (except Calozodion ).

Genera included: Calozodion Gardiner, 1973 ; Chondropodus Gutu, 2006 ; Hoplomachus Gutu, 2002 ; Julmarichardia Gutu, 1989 b; Trichapseudes Barnard, 1920 ; Vestigiramus Guţu, 2009 ; Zaraza, Gutu, 2006 ; Bamberus n. gen.

Remarks. According to Gutu (2008) one of the major features of the Chondropodinae is the presence of at least one apophysis on the antennule peduncle (as in Calozodion bacescui Gutu, 1996 or Calozodion singularis Gutu, 2002 ) and the presence of an apophysis on the upper margin of the first pereopod basis. Both characters are highly variable. The number of antennular apophyses can range from one to six in Calozodion and up to seven in some members of Julmarichardia while the number of apophyses on the pereopod can vary ontogenetically (Gutu 1984).

The number of setae on the terminal article of the exopod of the first pereopod wasn’t considered to be valid diagnosic character. Nevertheless many of the chondropodinids (as well as many members of Parapseudidae Gutu, 1981 ) have four or more plumose setae in contrast to members of Apseudidae Leach, 1813 .