Pagurapseudinae Lang, 1970, 1976

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2012, The Shallow-water Tanaidacea (Arthropoda: Malacostraca: Peracarida) of the Bass Strait, Victoria, Australia (other than the Tanaidae), Memoirs of Museum Victoria 69, pp. 1-235 : 63

Subfamily Pagurapseudinae Lang, 1970

The Pagurapseudinae incorporates species which are obligately adapted to living within gastropod shells, and show extreme morphological adaptations, often convergent with those of pagurid decapods. In particular, the pereon and pleon are twisted, the pleotelson consequently asymmetrical, the number of pleopods is usually reduced, the chelipeds are robust and often asymmetrical, the first pereopods are proportionately large (long), and the second to sixth pereopods bear rows of short, cylindrical spines or tubercles on the merus, carpus and propodus, used for gripping the inside of the empty snail-shell.

There are three genera described within this subfamily, Pagurapseudes Whitelegge 1901 , Pagurotanais Bouvier, 1918 , and Macrolabrum Băcescu, 1976 (b), but, as more species have been discovered over the years, there has been some confusion over the features which distinguish or characterize them (see Guţu, 1996b; Bamber, 2007; 2008). Pagurotanais is distinguished in having an exopodite present on the cheliped (absent in one species) but absent on pereopod 1 (these being respectively absent and present in the other two genera). Macrolabrum was distinguished by, and named for, an unusually long epistome exceeding the tip of the rostrum (anterior margin of the carapace) when viewed from above. In comparison with Pagurapseudes , this genus usually also has pronounced cheliped dimorphism in the male and robust distal setae or spines on the uropod endopod; other features which have been cited are the basis of pereopod 1 being conspicuously wider than subsequent articles, and the presence of large plumose setae on the maxilliped palp. However, some of these features are subjective, and some overlap these two genera as defined by the other characters. A further character, disregarded before but confirmed in the present material, which does serve to distinguish these genera consistently is the conformation of the pleopods. These are best developed in Pagurapseudes species, with two equal linguiform rami, each as long as the basis (protopod) and with a few setae on all margins (e.g. Fig. 44H), and present on at least 1 and up to 5 pereonites (juveniles have fewer pairs). In Macrolabrum species, the pleopods are present as only two pairs in adults, again well developed and biramous, but, while the exopod is similar to that of Pagurapseudes species, the endopod is characteristically shorter and almost circular (e.g. Fig. 50H). In Pagurotanais species, the pleopods are either absent entirely (including the generotype, see Bouvier, 1918), or present as a single pair, in the male only in one species, and of highly reduced form with the rami bearing 1 to 3 setae, and shorter than the basis. (e.g. McSweeney, 1982, figs 4G, 6C, unfortunately described as Pagurapseudes ). As the other features have not been found to be entirely consistent (e.g. the epistome of Macrolabrum distonyx Bamber, 2007 does not exceed the anterior margin of the carapace), this pleopod character is most stable in distinguishing the genera. As a result, Pagurapseudes abrucei Bãcescu 1981 , incidentally a species with a notably wide basis to pereopod 1 (less than twice as long as wide), is moved to Macrolabrum . The three genera may thus be keyed out as follows: 1. Pereopod 1 without exopodite; pleopods in the adult absent, or present as a single pair with reduced,

unequal rami shorter than basis and bearing 3 or fewer setae; epistome not exceeding anterior margin of carapace ... Pagurotanais

Pereopod 1 with conspicuous exopodite; pleopods present in the adult, with well-developed rami, at least one of which is linguiform and subequal in length to the basis ... 2 2. Rami of pleopods subequal in length, linguiform;

epistome not exceeding anterior margin of carapace

... Pagurapseudes

Endopod of pleopods circular and shorter than exopod; epistome usually (but not always) exceeding anterior margin of carapace ... Macrolabrum . The original material of the generotype Pagurapseudes spinipes , from New South Wales, probably included more than one species. The type-description clearly accords with a Pagurapseudes , and is good enough to recognize as a species. Those specimens which Whitelegge (1901) mentions as females having no pleopods may well have been Pagurotanais koonungai Bamber, 2008 (recorded from Brisbane), while his other specimens with less than three pleopods were possibly juveniles or other species. Five distinct species of the Pagurapseudinae were found in the Bass Strait material, all new, doubling the species complement for this subfamily in Australia.