Glandulotiron aotearoensis, Just, 2022

Just, Jean, 2022, Tirons of the world: a review of ‘ tironid’ amphipods, description of new genera and species, and establishment of a new subfamily Tironinae Stebbing, 1906 stat. nov. (Crustacea, Synopiidae), Zootaxa 5139 (1), pp. 1-89 : 58

Glandulotiron aotearoensis sp. nov.

( Figs 33–34 )

Type fixation. Holotype, ♀.—Here designated.

Etymology. ‘Aotearoa’ is the official Maori name for New Zealand, meaning ‘Land Of The Long White Cloud’.

Material examined. Holotype, ovigerous ♀, 10.8 mm. New Zealand, Otago Shelf , 45˚52’S, 171˚01’E, 500 m, gravel, sand, mud, P.K. Probert, RV Munida , stn MU 74 /202, 7 November 1974, NIWA 157581 . Unique.

Description. Rostrum triangular, about as long as wide at base, apex rounded. Interantennal lobes broadly rounded without upper and lower corners. Accessory eyes composed of 5 ommatidia.

Mouthparts. Maxilla 1 palp apex with 1 elongate, pointed lateral seta and 6 short, very broad setal spines with coarsely dentate lateral flange. Mouthparts otherwise normal.

Antenna 1 as long as pereonite 1–5 combined along dorsum, reaching to apex of antenna 2 article 4, peduncle article 2 about 0.6 length of article 1, article 3 about 0.6 length of article 2, article 1 with single penicillate seta ventrally and two middorsally; flagellum 0.9 length of peduncle, of 9 articles, distal articles with very long aestetasc, accessory flagellum of 4 articles. Antenna 2 as long as pereonites 1–6 combined along dorsum, peduncular article 4 the longest; flagellum of 9 articles, most articles with single short, curved robust seta dorsodistally, antenna otherwise with rows of small marginal setae.

Coxal plates 1–4 distally strongly crenulate and fringed with setae in indentations.

Gnathopods 1 and 2 of subequal length. Gnathopod 1 basis anterior margin with dense row of long and short setae and a several long setae in distal half of posterior margin; merus with simple long setae on posterior margin; carpus anterior margin with a few long setae in middle and group in distal corner, posterior margin with about 8 groups of long setae, middle 4 groups with slender, finely pectinate setae; propodus with a row of stout, coarsely pectinate setae on posterior margin; dactylus with unguis about 1/2 length of propodus, nearly straight. Gnathopod 2 basis anterior margin with a few long and row of short setae, posterior margin with several long setae, merus posterior margin with a few mid and distal setae, carpus slender, about 10 times longer than wide, with a few long setae on anterior margin, posterior margin with about 12 groups of long and shorter setae, propodus with a few short setae on anterior margin and several groups of longer setae on posterior margin, dactylus with unguis as gnathopod 1.

Pereopods 3–4 basis, ischium, merus and carpus with a few simple marginal setae, propodus with 3 stout anteroterminal robust seta.

Pereopod 5 basis narrowly oval, posterior margin distally with short rounded lobe, anterior margin with a few long simple setae proximally and some tiny setae more distally, ischium anterior margin with a few small simple setae, merus posterior margin with 2 robust setae, anterior margin with row of short robust setae, carpus with single robust seta posterodistally and double row of robust setae on anterior margin, propodus with 4 robust setae of varying length posterodistally. Pereopod 6 basis ovoid, anterior margin with long setae proximally and distally; remaining articles as in pereopod 5 with a few more setae. Pereopod 7 basis broader than in 5 and 6, of equal width proximally and distally, with broadly rounded posterior lobe, anterior margin with a few setae distally, medial surface with row of long setae, ischium anterior margin with distal tuft of long setae, merus posterior margin with several robust setae of different size, anterior margin with short and long setae and row of short robust setae in distal half, carpus longer and more slender than in pereopods 5 and 6, posterior margin with small robust seta in middle and in distal corner, anterior margin with row of short robust setae, propodus with robust setae of differing length posterodistally.

Uropod 1 peduncle reaching to about the end of peduncle of uropod 2, rami of equal length, about 1/2 length of peduncle, reaching as far as tips of uropod 2 rami, both uropods reaching 1/4 along outer ramus of pereopod 3. Uropod 2 inner ramus slightly longer than outer ramus. Uropod 3 peduncle about 2/3 as long as outer ramus, rami elongate oval, reaching beyond apex of telson, outer ramus basal article with row of 9 robust setae dorsally, distal 3 with additional medial robust seta, ventrally with 7 smaller robust setae, small second article with 3 robust setae, inner ramus covering 5/6 of basal article of outer ramus, dorsal margin with row of long setae and 2 robust setae, apex with 3 robust setae.

Telson. Length about 4.5 times greatest depth in lateral view, reaching 0.7 along outer ramus of uropod 3, dorsal view length/ width approximately 2.4. Each lobe with row of 3 robust setae, long, simple setae and a proximal group of 2 plumose seta dorsally on each lobe, apices with 1 long and 1 short robust seta.

Size. ♀, 10.8 mm. ♂ not known.

Distribution. New Zealand, off SE coast at Dunedin, 500 m.

Figures

FIGURE 33. Glandulotiron aotearoensis gen. et sp. nov. Holotype, ovigerous ♀. clv, head lateral view; mx1, maxilla 1; plp, maxilla 1 palp (*palp article 1 damaged); tel, telson; us, urosome.

FIGURE 34. Glandulotiron aotearoensis gen. et sp. nov. Holotype, ovigerous ♀. c2; coxal plate 2; gp1 and gp2, gnathopods 1 and 2; p4–p7¸ pereopods 4 –7.