Tuesday, January 31, 2017

[Crustacea • 2017] Pylopaguropsis mollymullerae • A New Species of Hermit Crab of the Genus Pylopaguropsis Alcock, 1905 (Anomura, Paguridae) from the Caribbean: “Den Commensal” or “Cleaner”?


Pylopaguropsis mollymullerae  Lemaitre, 2017

 In situ photographs of Pylopaguropsis mollymullerae sp. n. and its habitat at Bonaire diving site “Something Special”. holotype male 2.4 mm, Bonaire (USNM 1291987)  three individuals of Pmollymullerae sp. n. (foreground, not collected) in den with “broad banded moray” Channomuraena vittata

Abstract
A new secretive, yet brightly colored hermit crab species of the family Paguridae, Pylopaguropsis mollymullerae sp. n., is fully described based on specimens from the reefs of Bonaire, Lesser Antilles, southern Caribbean Sea. Populations of this new species were discovered and photographed in the Bonaire National Marine Park under a large coral ledge, at a depth of 13.7 m, living in crevices known by scuba divers to serve as den to a pair of “flaming reef lobsters” Enoplometopus antillensis, or a “broad banded moray” Channomuraena vittata. This new species is only the second species of Pylopaguropsis Alcock, 1905 known from the western Atlantic, the 20th named worldwide, and belongs in the teevana group of species of the genus. It is remarkably similar, and herein considered geminate, to the tropical eastern Pacific congener, P. teevana (Boone, 1932), the two being characterized and uniquely different from all other species of the genus, by the striking and deeply excavated, scoop-like ventral surface of the chela of the right cheliped. Minor differences separate this new species from P. teevana in the relative length of the antennal acicles (exceeding the corneas versus not exceeding the corneas in P. teevana); dorsal armature of the right chela (smooth or with scattered minute tubercles versus with numerous small tubercles in P. teevana); surface shape of the lateral face of the dactyl of right pereopod 3 (evenly convex versus flattened in P. teevana); and coloration (red bright red stripes versus brown stripes in P. teevana). The highly visible color pattern of bright red stripes on white background typical of decapods known to have cleaning symbioses with fish, dense setation on the flagella of the antennae, and preference for a crevicular habitat, combined with brief in situ nocturnal observations, suggests the possibility that P. mollymullerae sp. n. engages in “cleaner” activities or functions as a “den commensal” with moray eels. The morphology and possible meaning of the observed behavior is discussed. A tabular summary of the distribution, habitat, and published information on all species of Pylopaguropsis is presented. Supplemental photographs and a video of live P. mollymullerae sp. n. are included.

Keywords: Bonaire, Caribbean, “cleaner”, “den commensal”, hermit crab, new species, Paguridae, Pylopaguropsis


Systematic account 
Family Paguridae Latreille, 1802

Pylopaguropsis mollymullerae sp. n.

Figure 6. In situ photographs of Pylopaguropsis mollymullerae sp. n. and its habitat at Bonaire diving site “Something Special”. holotype male 2.4 mm, Bonaire (USNM 1291987) paratype male 1.8 mm, Bonaire (USNM 1291989) three individuals of Pmollymullerae sp. n. (foreground, not collected) in den with “broad banded moray” Channomuraena vittata coral ledge habitat, with arrow indicating entrance to crevice where five specimens of Pmollymullerae sp. n. were collected individual of P. mollymullerae sp. n. (expanded and enhanced in oval inset, not collected) on body surface of “broad banded moray” Cvittata, with frontal portion of brachyuran Achelous sebae visible on lower right.  
    

Figure 6. In situ photographs of Pylopaguropsis mollymullerae sp. n. and its habitat at Bonaire diving site “Something Special”. holotype male 2.4 mm, Bonaire (USNM 1291987) paratype male 1.8 mm, Bonaire (USNM 1291989) three individuals of Pmollymullerae sp. n. (foreground, not collected) in den with “broad banded moray” Channomuraena vittata coral ledge habitat, with arrow indicating entrance to crevice where five specimens of Pmollymullerae sp. n. were collected individual of P. mollymullerae sp. n. (expanded and enhanced in oval inset, not collected) on body surface of “broad banded moray” Cvittata, with frontal portion of brachyuran Achelous sebae visible on lower right.  

Distribution: So far known only from the island of Bonaire, Lesser Antilles, southern Caribbean Sea; depth: 11.6–13.7 m.

Etymology: The name of this new species is given to acknowledge the efforts of the collector, photographer and environmentalist, Ms Ellen Muller, who when informed of the intended honor, preferred that the name of her granddaughter, Ms Molly Muller, be used, in hopes to inspire her to continue the tradition of protecting the amazing and fragile diversity of marine life in Bonaire.

Common name: “Candy Striped Hermit Crab”, in reference to the bright white and red striped color pattern that is similar to that of traditional candy cane.


 Rafael Lemaitre. 2017. Discovery of A New Species of Hermit Crab of the Genus Pylopaguropsis Alcock, 1905 from the Caribbean: “Den Commensal” or “Cleaner”? (Crustacea, Anomura, Paguridae). ZooKeys. 646: 139-158. DOI:  10.3897/zookeys.646.11132


        

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