Sunamphitoe mixtura, Peart, Rachael A., 2017

Peart, Rachael A., 2017, Analysis of the genus Sunamphitoe Spence Bate, 1857 (Amphipoda: Ampithoidae) with descriptions of eight new species, Zootaxa 4269 (3), pp. 301-345 : 327-329

Sunamphitoe mixtura sp. nov.

( Figs 18–19 )

Ampithoe aorangi .— J.L. Barnard, 1972: 37 (part, sta. E978), fig. 10a–e.

Type material. Holotype: male, 7.8 mm, NIWA 892 , small high rock pools, in surf splash zone, lined with filamentous brown alga, Huaroa Point, Whangaparaoa Peninsula (Auckland Province), NZOI Sta. stn E978, coll. J.L. Barnard, 16 February 1968 .

Diagnosis. Mandibular palp with 3 articles. Maxilla 1 inner plate with two slender setae. Maxilla 2 inner plate much narrower than outer plate. Lower lip outer plate notched, lobes of equal height, medial lobe subacute apically. Gnathopod 2 carpus much shorter than propodus; propodus narrow, subtriangular; palm acute, excavate, sculptured, defining posterodistal tooth and robust seta present; dactylus subequal in length to palm, inner margin smooth with small setae. Uropod 3 peduncle with one distal robust seta, outer ramus with patch of lateral denticles, lateral setal fringe absent; inner ramus with three robust setae. Telson distally subacute, apical cusps are small, with apical and lateral setae and with lateral denticles.

Description. (Based on holotype male, 7.8 mm, NIWA 892.)

Head. Head as long as deep. Antennae broken off. Mandibular molar well developed, triturating, with ten robust setae in accessory setal row; palp slender, long, apically setose, article 1 shorter than article 2 (0.7 ×), article 2 longer than article 3 (1.2 ×), article 3 longer than article 2 (1.2 ×), articles 2 and 3 with marginal setules. Maxilla 1 palp well developed, with apical robust setae. Maxilliped outer plate large with large and numerous setae, narrow apically, reaching midlength of palp article 3; palp article 4 with marginal setules.

Pereon. Gnathopod 1 smaller than gnathopod 2; coxa 1 not produced anteroventrally, anteroventral corner rounded, slight nipple-shaped protubence, ventral margin with row of small setules and tuft of longer setae on posterodistal corner, anterior and ventral margins lined with fine setae; basis longer than coxa, with lateral and medial plumose setae, proximal margins with fine setae, anterodistal lobe medium and rounded with three marginal small setae; merus produced to form small subacute- rounded, distoventral lobe, anterior margin with setae absent; carpus longer than merus, subtriangular, subequal in length to propodus (0.9 ×), carpal lobe slightly truncated, anterior margin with distal slender setae only; propodus narrow (length 1.9 × width), subrectangular; palm transverse, entire, without posterodistal tooth defining palm, with one defining robust seta; dactylus overreaching palm, inner margin serrated; posterior margins of merus, carpus and propodus fringed with fine setae. Gnathopod 2 sparsely setose; coxa ventral margin without setae, but with small fine setae covering medial surface; basis longer than coxa, with sparse marginal setae and anterior margin lined with fine setae, anterodistal lobe medium and rounded lined with row of setae; merus produced to form medium sized acute distoventral lobe, anterior margin with setae absent; carpus subequal in length to merus, subtriangular, anterior margin with patches of small setae; propodus subtriangular, not produced into anterodistally setose lobe; dactylus tapering evenly, acute, inner margin smooth.

Pereopods 3–4 basis and merus expanded; basis with robust seta on margin and lined with fine setae and plumose setae. Pereopods 5–7 missing.

Pleon. Epimeron not documented. Uropod 1 peduncle with 10 marginal robust setae, and with long plumose, setal fringe; inner ramus longer than outer ramus, with four marginal robust setae; outer ramus broader than inner ramus and with eight marginal robust setae. Uropod 2 peduncle with four robust setae; inner ramus longer than outer ramus, with four marginal robust setae; outer ramus broader than inner, and with nine marginal robust setae. Uropod 3 peduncle longer than broad (2 × width), long in relation to rami length (3.3 ×), marginal robust setae absent, marginal slender setae in two bundles (made up of five setae and two setae); rami broad, outer ramus shorter than inner ramus; inner ramus with one distal robust seta.

Etymology. Mixtura is a Latin substantive derived from the verbs to mix or confuse. It is indicating the confusion arising from the nature of the original description.

Remarks. Material of Sunamphitoe mixtura sp. nov. was originally reported as a growth variant of S. aorangi ( J.L. Barnard, 1972) . While there are some characters that could be ascribed to a later growth stage, the majority of differences are not associated with body size and not mentioned by Barnard (1972). One of Barnard’s (1972) original specimens is made the holotype of this new species. The differences between S. mixtura , S. aorangi and the similar S. lehae are given in detail in Table 1 and in the remarks for S. lehae sp. nov.

Distribution. Northern New Zealand.

Figures

FIGURE 18. Sunamphitoe mixtura sp. nov., holotype male, 7.8 mm, NIWA 892, Huaroa Point, Whangaparaoa Peninsula, New Zealand. Scales 0.1 mm for LL, Lmd, Mxp and Mx 1; 0.2 mm for Rmd, Mx 2, U 2 – 3, and T; and 0.5 mm for U 1.

FIGURE 19. Sunamphitoe mixtura sp. nov., holotype male, 7.8 mm, NIWA 892, Huaroa Point, Whangaparaoa Peninsula, New Zealand. Scales 0.5 mm.