Naushonia Kingsley, 1897

Komai, Tomoyuki & Anker, Arthur, 2015, Additional records of the laomediid mud-shrimp genus Naushonia Kingsley, 1897 (Crustacea: Decapoda: Gebiidea), with a revised identification key, Zootaxa 3974 (3), pp. 341-360 : 342-343

Genus Naushonia Kingsley, 1897

Emended diagnosis. Laomediid mud shrimps with firm, well-calcified integument. Carapace with well-marked linea thalassinica, running entire or almost entire length of carapace; rostrum well developed, rounded or pointed distally, with variable armature; postorbital spine simple; branchiostegal spine usually strong; carapace armature extremely variable, ranging from low carinae with small granules to prominent crests and rows of strong spines. Pleon with first somite short, second to sixth somites subequal in length; dorsolateral surface of pleomeres typically smooth or with faint carinae, sometimes with stronger armature consisting of crests, spines and tubercles; pleural margins entire or variously toothed. Telson with posterior margin convex, with or without spines on lateral margin; dorsal surface usually armed with spines or tubercles. Eye relatively small, cornea with normal or reduced pigmentation. Antennular peduncle with second and third segments not particularly elongate. Antennal peduncle with well-developed, laterally toothed scaphocerite. Mandible with sharp teeth along entire distal edge of incisor process; palp with three articles. First maxilliped with large endopod and well-developed epipod. Second maxilliped with scaphognathite furnished with long posterior setae. Third maxilliped pediform, with welldeveloped crista dentata on ischium; exopod well developed. First pereopods subchelate, symmetrical, carried with dactylus in distolateral position relative to dorsoventrally flattened palm; occlusal (= cutting) margin of palm more or less denticulate, often with strong teeth. Second pereopod non-chelate; dactylus with dense setal brush on dorsal to lateral surfaces. Dactyli of third to fifth pereopods each with thin, comb-like, toothed lamina on flexor margin. First pleopods absent in male, uniramous in female; second to fifth pleopods biramous, without appendices internae, male second pleopod without appendix masculina. Uropods with complete, finely toothed diaeresis on both exopod and endopod. For branchial formula, see Table 1 and “Remarks” below.

Thoracic somites 1 2 3 4 5 6 7 8 Appendages Maxillipeds Pereopods

1 2 3 1 2 3 4 5 Pleurobranch 0 0 0 0 0 0 0 0 Arthrobranchs 1 2 2 2 2 2 2 0 Podobranchs 0 1 1 1 1 1 0/r 0 Epipods 1 1 1 1 1 1 1 0 Mastigobranchs 0 0 1 1 1 1 1 0 Exopod 1 1 1 0 0 0 0 0 Setobranchs 0 0 1 1 1 1 1/0* 0 Remarks. As noted by Anker (2014), the branchial formula of Naushonia remains incompletely known, due partly to the rarity of specimens, particularly in species formerly assigned to Espeleonaushonia . In fact, the complete branchial formula remains unknown in N. augudrea , N. macginitiei , N. manningi , N. palauensis , N. panamensis , and N. perrieri , and was also unknown, until now, in N. draconis and N. japonica (see below). The presence/absence of an arthrobranch on the first maxilliped and of a podobranch on the fourth pereopod appear to be intragenerically variable characters in Naushonia ( Anker 2014) . Considering the difficulties to observe the basal area of the anterior maxillipeds, we tried to verify the presence or absence of an arthrobranch at the base of the first maxilliped in the six species treated in this study, through a careful dissection of the upper-lying appendages. We here confirm that one arthrobranch is constantly present on the first maxilliped in all six species, although this gill was previously reported as absent in N. carinata ( Dworschak et al. 2006) , which was confirmed by a reexamination of the two paratypes of this species by Peter C. Dworschak (see “Remarks” under N. carinata ). The podobranch on the fourth pereopod is absent or greatly reduced to a rudimentary bud in all six species reported in this study.

Martin & Abele (1982: 482, key) were the first to use the shape of the postorbital spines of the carapace as one of the key characters differentiating species of Naushonia , i.e., “simple” in N. panamensis , versus “bifid or trifid” in N. crangonoides , N. portoricensis and N. macginitiei . This distinction originates from the somewhat diagrammatic figures of the carapace in Goy & Provenzano (1978: fig. 6A–D), in which the postorbital spines were illustrated as simple in N. perrieri , and as bifid or multifid in N. crangonoides , N. macginitiei and N. portoricensis . Martin & Abele’s (1982) key has been followed by all successive workers expanding their keys to include additional species, i.e., Berggren (1992), Alvarez et al. (2000), Komai & Anker (2010), and Anker (2014). However, during this study, we examined a specimen of Naushonia from St. Martin, French Antilles, which agrees well with N. portoricensis , except for the presence of a simple, acuminate, postorbital spine. This observation raised the question whether the postorbital spine is bifid or multifid in the three above-listed American species of Naushonia . Original descriptions of N. crangonoides , N. macginitiei and N. portoricensis do not specifically describe the structure of the postorbital spine, however, all published figures actually appear to show simple postorbital spines ( Kingsley 1897; Rathbun 1901; Thompson 1903; Glassell 1938; Chace 1939). In order to clarify this problem, we asked Dr. Rafael Lemaitre ( USNM) to re-examine material of Naushonia studied by Goy & Provenzano (1979: pp. 348–351), viz. N. crangonoides ( USNM 34143, 102277, 102279, 102280), N. portoricensis (holotype: USNM 23782, 155101), and N. macginitiei ( USNM 171604, 171605, 14449). Dr. R. Lemaitre (pers. comm., 12 August 2014) informed us that none of the USNM specimens has bifid or multifid postorbital spines. It can be concluded that more generally, all species of Naushonia have simple postorbital spines and never bifid or multifid spines, thus making previous identification keys extremely ambiguous. Therefore, a new, fully revised identification key to all presently known species of Naushonia is presented below.