Decaphyllus de Saint Laurent, 1968

Komai, Tomoyuki & Rahayu, Dwi Listyo, 2013, Six New Species Of The Hermit Crab Genus Decaphyllus De Saint Laurent, 1968 (Crustacea: Decapoda: Anomura: Paguridae) From The Boholo Sea, The Philippines, And The Ryukyu Islands, Japan, Raffles Bulletin of Zoology 61 (2), pp. 589-620 : 590

Decaphyllus de Saint Laurent, 1968

Decaphyllus de Saint Laurent, 1968a: 925 ; 1968b: 1100; McLaughlin, 1997: 447; 2003: 121.

Remarks. — As discussed by de Saint Laurent (1968a, 1968b), Decaphyllus appears closest to Catapaguroides . Differentiating characters between the two genera are well presented by de Saint Laurent (1968a, 1968b), though McLaughlin (1997) proposed an emended generic diagnosis to accommodate the new species described by her. The six new species described in this study fall within the generic diagnosis of McLaughlin (1997, 2003). Practically, Decaphyllus can be distinguished from Catapaguroides by the setose ambulatory dactyli lacking any armature, the non-chelate fourth pereopods with the dactylus bearing thick setae covering terminal claw, and the characteristic shape of the telson. In addition to these characters mentioned by previous authors, we noticed that the following characters are supplemental in differentiating species of Decaphyllus from those of Catapaguroides : ocular peduncle having dorsal or dorsomesial row of tufts of long setae (such tufts of setae absent in Catapaguroides ); ultimate segment of antennular peduncle without one or two long feathered setae on dorsolateral distal angle (these long setae present in Catapaguroides ); meri of both chelipeds bearing a proximoventral protuberance or spine on mesial surface (no such protuberance or spine in Catapaguroides ); ischia of both chelipeds bearing two widely spaced small spine or spinules on ventromesial margin (such spines absent in Catapaguroides ).

During this study, we have found reduction or loss of the

arthrobranchs on the third maxilliped is rather widely seen in species of Decaphyllus (see Table 1), like in species of Catapaguroides (cf. Komai & Rahayu, 2013). The complete loss of those gills is seen in D. deliquus , new species, in addition to D. barunajaya . In D. litoralis , new species, there is only a single arthrobranch strongly reduced to a minute, simple bud. In the other species examined in this study, the arthrobranchs are very small in size, often reduced to non-lamellate, bud-like structure. Therefore, it is reasonable to consider that the loss of the arthrobranchs on the third maxilliped could not be diagnostic alone at genus level.