Pseudopontophilus, Komai, 2004

Komai, Tomoyuki, 2004, A new genus and new species of Crangonidae (Crustacea, Decapoda, Caridea) from the southwestern Pacific, Zoosystema 26 (1), pp. 73-85 : 74-76

Genus Pseudopontophilus n. gen.

TYPE SPECIES. — Pseudopontophilus serratus n. sp.

ETYMOLOGY. — From the Greek pseudes meaning false, and Pontophilus , a generic name proposed by Leach (1817), and referring the superficial similarity of this new genus to the genus Pontophilus .

DIAGNOSIS. — Rostrum armed with one pair of lateral teeth. Carapace with postorbital suture; midline with more than two spines in anterior 0.60, but no spine on posterior 0.40; one additional spine superior to antennal spine; postorbital carina low, blunt, bearing three epibranchial spines. Anterior five abdominal somites devoid of median carinae; sixth somite without submedian carinae. Eye with cornea well developed, darkly pigmented. Antennular stylocerite not expanded laterally, terminating distally in acute spine. Scaphocerite with well developed blade. Maxilla with posterior lobe of scaphognathite rounded, not greatly elongate. First pereopod without exopod. Second pereopod chelate, short, but reaching distal end of merus of first pereopod; ischium and basis partially fused. Podobranch on second maxilliped; one arthrobranch above third maxilliped; pleurobranchs on fourth to eighth thoracic somites, each with anteriorly directed dorsal apex. Appendix masculina shorter and broader than appendix interna.

REMARKS

The new genus, which at present contains only the type species, is placed closest to Pontophilus and Parapontophilus using the key provided by Holthuis (1993). The three genera share the rostrum armed with at least one pair of lateral teeth, shortened but chelate second pereopod, and the postorbital suture on the carapace. Pseudopontophilus n. gen. differs from both Pontophilus and Parapontophilus in the completely loss of an exopod on the first pereopod and the more well developed second pereopod which reaches to the distal margin of the merus of the forwardly direct- ed first pereopod. The presence of more than two median spines in the anterior 0.70 on the carapace also characterizes Pseudopontophilus n. gen. In some characters, the new genus appears intermediate between Pontophilus and Parapontophilus . In the general spination of the carapace (there are more than two median spines and more than one epibranchial spines), Pseudopontophilus n. gen. is similar to Pontophilus , although no middorsal spine is present in the posterior half on the carapace in the new genus. While, the smooth abdomen lacking median or submedian carinae and the short, robust appendix masculina relate Pseudopontophilus n. gen. to Parapontophilus .

Further, Pseudopontophilus n. gen. superficially resembles Philocheras Stebbing, 1900 in general appearance. The possession of the postorbital longitudinal suture on the carapace and the nontransversely oblong antennular stylocerite immediately distinguish the new genus from Philocheras . The presence of a pair of lateral teeth on the rostrum is useful to separate Pseudopontophilus serratus n. gen., n. sp. from all but two species of Philocheras , P. gorei ( Dardeau, 1980) and P. lapillus Wicksten, 1983 , both of which are known to have lateral rostral teeth ( Dardeau 1980; Wicksten 1983). It is recommended to reassess the phylogenetic position of the latter two Philocheras species.