Pusillopagurus, Lemaitre & Felder & Poupin, 2017

Lemaitre, Rafael, Felder, Darryl L. & Poupin, Joseph, 2017, Discovery of a new micro-pagurid fauna (Crustacea: Decapoda: Paguridae) in the Lesser Antilles, Caribbean Sea, Zoosystema 39 (2), pp. 151-195 : 187

Genus Pusillopagurus n. gen.

TYPE SPECIES. — Pusillopagurus polulus n. gen., n. sp., by present designation. Gender: masculine.

ETYMOLOGY. — The generic name is a combination of the genus name Pagurus with the Latin pusillus , which refers to something very small, and used in reference to the minuscule size of specimens in the single species of this new genus.

DISTRIBUTION. — Known based on the type species found in Curaçao, at a depth of 15.2-115.8 m.

DIAGNOSIS. — Eight pairs of biserial phyllobranch gills, only 1 pleurobranch on somite XII (thoracomere 7, above pereopod 4). Rostrum triangular. Ischium edge of crista dentata projected medially, lacking accessory tooth. Chelipeds subequal in length, somewhat slender. Sternite of somite XI (thoracomere 6, pereopod 3) with anterior lobe subrectangular, bilobed. Pereopod 4 with single row of scales on propodal rasp, dactyl lacking preungual process. Pereopod 5 semi-chelate. Male with coxae of pereopods 5 symmetrical, with paired, unequal sexual tubes, right tube much longer than left, distally coiled and filamentous, left tube not coiled or filamentous; with unpaired, left pleopods 3-5. Female with paired gonopores, and unpaired, left pleopods 2-5. Telson nearly symmetrical, longer than broad, with lateral indentations dividing anterior and posterior lobes; terminal margins of posterior lobes weakly oblique, armed with distinct spines.

REMARKS

There are no clear morphological similarities between this new genus and other known pagurid genera in which the male has sexual tubes, despite some having similar sexual tubes. As in Pusillopagurus n. gen. and at least 18 other pagurid genera in which the male has paired sexual tubes, the right is longer than the left. In general morphology, the tubes of Pusillopagurus n. gen. are most similar to those of Trichopagurus de Saint Laurent, 1968 (described in more detail in de Saint Laurent [1970b]), and to a lesser extent those of Alainopaguroides McLaughlin, 1997 and Icelopagurus McLaughlin, 1997 . However, in most other important morphological features, such as the cephalic shield and appendages, third maxilliped crista dentata, chelipeds, ambulatory legs, and telson, Pusillopagurus n. gen. differs markedly from these three genera. Furthermore, the number of gills in this new genus is eight, whereas it is 11 in those other three.