- Reinstatement and Rediagnosis of Catapaguroides setosus and Description of a Second Hawaiian Species of the Genus (Decapoda: Anomura: Paguridea: Paguridae)1
A species of the hermit crab genus Catapaguroides recently discovered in a sand-dwelling Halimeda community on the island of Maui, Hawaiian Islands, prompted a reexamination of the holotype of Catapaguroides setosus (Edmondson, 1951), described from off the south coast of O'ahu. The latter species, currently considered a junior subjective synonym of Catapaguroides fragilis (Melin), is herein adjudged neither synonymous with C. fragilis nor conspecific with the second Hawaiian species. Catapaguroides setosus is reinstated with full specific rank, rediagnosed, and illustrated. The second species, Catapaguroides hooveri McLaughlin & Pittman, n. sp., is described and illustrated.
As part of the bycatch of a 1998-1999 survey of Hawaiian opisthobranch mollusks at a site 1.6 km north of Keka'a Point, on the island of Maui, Hawaiian Islands, the attention of one of the authors (C.P.) was drawn to a colorful, fast-moving, tiny hermit crab. Several very small hermit crab species are known from the shallow waters of the Hawaiian Islands (e.g., Edmondson 1951, McLaughlin and Haig 1984, McLaughlin 1986); however, this is the first species recognized exclusively from the sand-dwelling Halimeda community. This hermit crab has been found to represent an undescribed species of the genus Catapaguroides A. Milne-Edwards & Bouvier, 1892.
In her revision of the genera Catapaguroides and Cestopagurus, de Saint Laurent (1968) transferred the Hawaiian Cestopagurus setosus Edmondson, 1951, to the genus Catapaguroides, and placed it in synonymy with Catapaguroides fragilis (Melin, 1939). De Saint Laurent (1968) had compared Edmondson's (1951) male holotype with the "mutilated" male holotype of Melin's species and a small female collected from Mururoa. Although de Saint Laurent noted certain differences among the three, she provisionally considered all three to represent a single taxon. She illustrated only the right cheliped of the Mururoan specimen.
As noted by McLaughlin (2001), the holotype of Catapaguroides [as Eupagurus (Catapagurus)] fragilis is represented in the collections of the Museum of Evolutionary Zoology (MEZ), Uppsala, Sweden, by a series of 11 slides (MEZ 439 a-k) of the antennules, antennae, first through third maxillipeds, right second pereopod, and right fifth pereopod. The body and detached left cheliped, in the collection of the Swedish Museum of Natural History, Stockholm (SMNH), represent the "mutilated" specimen (SMNH Type-2291) examined by de Saint Laurent (1968). Neither Melin's (1939) specimen, nor the Mururoa specimen appear to be conspecific with Edmondson's (1951) taxon, the holotype of which is preserved in the collections of the Bernice P. Bishop Museum (BPBM), nor with the new species described here.
Materials and Methods
Opisthobranch sampling in the Halimeda beds consisted of two types. To sample the [End Page 41] alga itself, a glove with paintbrush bristles attached to the fingers was swept by a diver though the clumps and the "plankton" generated was scooped into a 0.25-mm mesh, tubular net. To sample the sand-dwelling species, the sand was either scooped or swept into a 1.0-mm mesh sieve by the diver and sieved in the field, with the retained residue bagged for later examination under a dissecting microscope. The sieved hermit crabs were initially preserved in 10% formalin and later transferred to 70% ethyl alcohol for storage.
Catapaguroides setosus is herein rediagnosed from its holotype (still the only known specimen) and compared with C. fragilis and C. hooveri, n. sp. The holotype of C. hooveri, n. sp., and the illustrated paratypes have been deposited in the collections of the National Museum of Natural History, Smithsonian Institution (USNM). Additional paratypes are deposited in the collection of the Bishop Museum. General terminology for the species diagnosis and/or description follows that of McLaughlin (1997). One measurement, shield length (sl), as measured from the midpoint of the rostral lobe to the midpoint of the posterior margin of the shield, provides an indication of animal size. The abbreviation ovig. indicates ovigerous females.
Catapaguroides setosus (Edmondson, 1951) Figure 1A-D
Cestopagurus setosus Edmondson, 1951:200, fig. 9.
Catapaguroides setosus: de Saint Laurent, 1968:941.
Holotype ♂ (sl = 1.6 mm...