Solitariopagurus tuerkayi McLaughlin, 1997

Martin, Joel W., Moffitt, Robert B. & Mclaughlin, Patsy A., 2009, Additions to the decapod crustacean fauna of the Hawaiian Islands, II. First record of the unusual hermit crab genera Porcellanopagurus Filhol, 1885, and Solitariopagurus Türkay, 1986 (Decapoda, Anomura, Paguridae), Zootaxa 2057, pp. 53-62 : 60

Solitariopagurus tuerkayi McLaughlin, 1997

( Fig. 1 B, 4B)

Solitariopagurus tuerkayi McLaughlin, 1997: 461 , fig. 8; 2000: 408, fig. 8.

Material. One ♂ (SL 3.2 mm, SW 3.5 mm), Hawaii, Penguin Banks (off southwest coast of Moloka'i), National Marine Fisheries Service cruise OES 03-01, station 27, 16 February 2003, 20°59.458'N, 157°25.809'W, 12-foot shrimp trawl, 153 m, inhabiting (wearing) one valve of a small bivalve mollusk (family Lucinidae , Ctena bella (Conrad, 1837) , Lindsey Groves, LACM, personal communication) ( LACM CR 2003-046.1),.

Coloration. Based on photographs taken immediately after collecting and/or freezing the fresh specimens (photographs in the collection of RBM), the background color is light orange with blotches of red or reddishbrown ( Fig. 4 B). Pereopods 2 and 3 are reddish-orange, lightly banded with white or cream; the distal end of each article is translucent pale or white. Another photograph (that of a different specimen, the missing ovigerous female noted below) shows a background color of pale cream, with patches of reddish-brown restricted to the front and anterolateral regions of the shield and on the pereopods, especially on the dorsal borders of both chelae where the pigment occurs in a longitudinal dorsal stripe. The pleon is cream flecked with reddish-brown. Eggs, carried dorsally, are a yellowish-orange in one photograph. The eyestalks have a central longitudinal region of beige or ivory flanked on either side by reddish-brown. The four prominent rounded tubercles on the anterodorsal region of the shield are tipped with white. Four years after collecting and preservation, the carapace and legs are a pale or translucent white, and the eyes are a dusky orangeyellow. McLaughlin (1997) similarly noted a faint orange tint on the chelae and dactyls of the pereopods as well as faint banding on the legs of a specimen that had been preserved for four years in alcohol ( McLaughlin 1997, 2000).

Remarks. Solitariopagurus tuerkayi is readily separated from other species in the genus by a combination of characters. It differs from S. profundus in its possession of the four obvious dorsal bumps or protuberances just proximal to the front of the carapace ( Fig. 1 B), a character that S. tuerkayi shares with S. triprobolus and S. trullirostris . However, it differs from S. trullirostris in having a longer and slenderer rostrum and in lacking protuberances on the eyestalks, and it differs from S. triprobolus in lacking additional (lateral and posterior) dorsal protuberances on the shield and in the relative lengths of the eyestalks and antennular peduncle (see McLaughlin 2000).

Morphologically, the Hawaiian specimen ( Fig. 1 B, 4B) agrees well with previous descriptions of this species ( McLaughlin 1997, 2000). Slight differences exist in the spination of the articles of the chelipeds (our specimen has less prominent dorsal ridges on the carpus than described previously, and indeed these are not even depicted in Fig. 1 B) and in the relative size of the eyestalks compared to the carapace (eyestalks appear smaller in the Hawaiian specimen). The Hawaiian specimen is slightly larger (SL 3.2 mm) than either of the two specimens mentioned or illustrated by McLaughlin (2000) (SL 2.9 and 2.1 mm), and these differences may well be size-related. Because of the rarity of specimens of this species and in this genus, a full understanding of variability within species is not yet possible.

Our specimen is the first record of the genus for the Hawaiian Islands, and the second report of the genus from the northern hemisphere. The other report of the genus from the northern hemisphere is also of this same species, Solitariopagurus tuerkayi , and is based on McLaughlin's (2000) record of a specimen from Okinawa. Previous distributional records include the Kai and Tanimbar Islands, Indonesia, New Caledonia, and Okinawa ( Japan) (McLaughlin 2000: 408). This report is apparently the first record of this species inhabiting (wearing) half of a bivalve shell, a finding that is not surprising given that two of the three other members of the genus ( S. trullirostris and S. triprobolus ) have been reported to do likewise (McLaughlin 2000).

Additionally, a photograph taken on board the ship soon after collecting shows a different specimen of this same species, an ovigerous female photographed next to half of a bivalve shell. This additional female specimen (also from Penguin Banks, Pisces IV, Dive 0 66, 20° 58.414' N, 157° 22.211'W at 200 m depth) has not yet been located in our collections. The bivalve in this photograph is a mytilid, Septifer rudis Dall, Bartsch , and Rehder, 1938, a species known only from Hawaii in depths of 30 to 100 m (Lindsey Groves, personal communication).

Figures

FIGURE 1. A, Porcellanopagurus platei Lenz, 1902, ovigerous female, Hawaii (LACM CR 2006 - 013.1). B, Solitariopagurus tuerkayi McLaughlin, 1997, ovigerous female, Hawaii (LACM CR 2003 - 046.1) Scale bar applies to both figures.

FIGURE 4. A, Porcellanopagurus platei Lenz, 1902, color photograph of ovigerous female (LACM CR 2006 - 013.1) taken approximately 1 year after collection. B, Solitariopagurus tuerkayi McLaughlin, 1997, color photograph of male (LACM CR 2003 - 046.1) taken by RBM immediately after collecting.