Glandulotiron griffithsi, 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 : 64-67

Glandulotiron griffithsi sp. nov.

Figs 37–38

Type fixation. Holotype, ♀.—Here designated.

Etymology. This species is named for Professor, Dr. Charles L. Griffiths (University of Cape Town) in recognition of his work on South African Amphipoda .

Material examined. Holotype, ♀, 11.3 mm. South Africa, False Bay, 9.8 nm [17.5 km] NE of Cape Point , 34˚20’S, 18˚31’E, 30 m, shells, Galathea Expedition 1950 –52, stn 166, 3 January 1950, NHMD 916117 .

Paratypes. Same data as holotype, NHMD 916118 (1 ♂, 7.9 mm, 1 ♀) .

Description (female). Rostrum bluntly pointed. Interantennal lobes broadly rounded. Accessory eye composed of 5 ommatidia in loose crescent.

Mouthparts. Maxilla 1 palp with 5 short bi- or tri-cusped setae and single lateral serrate seta; outer plate with row of 10 setae of varying denticulation; inner plate with rounded apex, without noticeable gap between distal two setae and more posterior ones. Mouthparts otherwise normal.

Antenna 1 as long as pereonite 1–5 combined along dorsum, peduncle article 2 about two thirds length of 1, article 3 about 3/4 length of 2, article 1 with single penicillate seta ventrally in posterior half and 3 middorsally, laterally in distal half with row of short stiff setae, flagellum as long as peduncle, of 9 articles, assessory flagellum of 4+ articles. Antenna 2 as long as pereonites 1–6 and half of 7 combined along dorsum, peduncular article 4 the longest, with 3 long plumose setae dorsally, flagellum of 8+ articles, several articles with single slender robust seta distally.

Coxal plates 1–4 distally fringed with simple setae, without brim of fine setules.

Gnathopods 1 and 2, basis about 1/5 longer than carpus. Gnathopod 1 propodus about half as long as carpus, dactylus with unguis half as long as propodus, straight, carpus with scattered long setae on anterior margin, posterior margin with long setae, propodus with pectinate setae. Gnathopod 2 propodus slightly shorter than carpus, carpus anterior margin as in gnathopod 1, posterior margin with about 10 groups of long, heavily plumose setae, ischium and merus with similar setae on posterior margin.

Pereopods 3–4 basis with setae of varying length on anterior margin, posterior margin nearly without setae, ischium to propodus with few distal simple setae, propodus with long, straight robust seta anterodistally.

Pereopods 5–7, with strongly plumose long setae on anterior margin of basis, ischium and merus (see Fig. 36 , p 6 arrows), with row of long setae on medial surface, basis with posterodistal rounded projection. Pereopod 5 basis broadest distally with slightly concave posterior margin. Pereopod 6 posterior margin straight. Pereopod 7 basis about as long as proximal width, with broad rounded posteroproximal lobe, posterodistally with shallow, broadly rounded lobe, merus and carpus posterior margin with ‘felt’ of fine setules, propodus about half as long as carpus, carpus with groups of small robust setae on anterior margin.

Uropod 1 peduncle reaching to end of uropod 2 peduncle, rami of equal length, nearly as long as peduncle, with a few small robust setae, reaching 1/3 length of basal article of uropod 3 outer ramus. Uropod 2 peduncle with a few small robust setae dorsally, outer ramus about 1/2 length of inner ramus. Uropod 3 peduncle about 3/4 length of rami, rami elongate oval, reaching well beyond apex of telson, outer ramus main article with 10 robust setae dorsolaterally, ventrally with dense felt of tiny setules, inner ramus reaching nearly to end of basal article of outer ramus, dorsal margin with row of long plumose setae and 3 robust setae in distal third; both rami with small robust setae in hollow.

Telson reaching to 1/2 outer ramus of uropod 3, with row of 4 or 5 robust setae, doublet of plumose setae, and several long simple setae on each lobe; length about 6.7 times greatest width in dorsal view.

Male. Generally as female except gnathopod 2 setae not plumose; antenna 1 flagellum article 1 with 2 medial double-row callynophore of about 10 long aestetascs per row; antenna 2 flagellum of 6+ articles.

Size. Largest ♀, 11.3 mm. Largest ♂, 7.9 mm.

Distribution. South Africa, Southwestern Cape Province, False Bay, 30 m.

Remarks. It became important to compare these new specimens with Stebbing’s (1908) Tiron [now Glandulotiron ] australis from South Africa (see above), but a visit to the BMNH or loan of material was not possible due to the current pandemic situation. I am grateful to Dr Lauren Hughes, Principal Curator in Charge of BMNH’s Crustacea collections, for checking certain characters on Stebbing’s ovigerous female syntype against my drawings of a female Glandulotiron s pecimen from farther west along the South African Coast. As a result of that examination it is evident that females of the western species differ from Stebbing’s female syntype on the following points ( Glandulotiron australis in parentheses): maxilla 1 inner plate has a continuous curved fringe of setae (a concave gap between an apical tuft of setae and the more posterior fringe); antenna 1 barely reaching distal end of antenna 2 peduncle (antenna 1 reaching beyond antenna 2 peduncle with at least 2 articles); gnathopod 2 carpus length/midwidth 4.2 (6.7); gnathopod 2 ischium, merus and carpus with heavily plumose setae on posterior margin (simple slender setae); pereopod 6 basis of equal proximal and distal width (much wider distally); uropod 3 outer ramus with felt of tiny setules covering ventral margin (at most some simple setae). By this suite of characters Glandulotiron griffithsi sp. nov. is distinctly different from G. australis Stebbing.

Figures

FIGURE 6. Tiron sagamiense sp. nov. Holotype. clv, head lateral view; gp1–gp2, gnathopods 1 and 2; ple 3, pleonite 3 posterior margin; us, urosome.

FIGURE 36. Glandulotiron postremus gen. et sp. nov. Holotype, ♀. cox3, coxal plate 3; gp1–gp2, gnathopods 1 and 2; p4–p7; pereopods 4 to 7; tel, telson with glands in left lobe indicated.

FIGURE 37. Glandulotiron griffithsi sp. nov. Holotype, ♀, except M, ♂, paratype. a and b, length of antenna 1 accessory flagellum and flagellum respectively; a1 flag, ♂ article 1 of antenna 1 flagellum with callynophore indicated; clv, head lateral view; mx1 maxilla 1; tel, telson; us, urosome.

FIGURE 38. Glandulotiron griffithsi gen. et sp. nov. Holotype, ♀. gp1–2, gnathopods 1 and 2; p3, pereopod 3; p5–7, pereopods 5–7 (5 broken distal to carpus); s, heavily plumose setae; x, pereopod 6 apex of propodus with stubby dactylus.