Takereana festiva (Chilton, 1885) Chilton, 1885

Poore, Gary C. B. & Hurley, Desmond E., 2015, Takereana, a new genus of Idoteidae (Crustacea: Isopoda: Valvifera) from New Zealand, Zootaxa 4057 (4), pp. 590-594 : 593

Takereana festiva (Chilton, 1885) comb. nov.

Figs 1 , 2

Idotea festiva Chilton, 1885a: 320 –321.— Chilton 1885b: 123 –125, pl. 5, figs A.1–3.— Thomson & Chilton 1886: 156 (list).— Chilton 1890: 190, 192–193.— Poore & Lew Ton 1993: 199.

Material examined. Holotype. New Zealand, Canterbury, Sumner, 43°334'S, 172°46'E, CMNZ (ovigerous female, 10.3 mm; formerly glued to microslide, now rehydrated).

Other material. New Zealand. New Brighton, 43°30'S, 172°44'E, ‘in clump of the polyzoan Flustrella binderi which it exactly resembles in colour’, E.W. Bennett, 2 Jul 1927, CMNZ (juvenile male, 9.1 mm). Island Bay, 41°20'S, 174°46'E, rocky shore, under rocks at low tide, N.L. Bruce, 17 Dec 2004 (stn NZOI Z15016), NIWA 104910 (2 ovigerous females, 9.5, 10.1 mm).

Description. Body and all limbs covered by a dense mat of oblique cuticular scales (figs 1c, 2i; not otherwise figured). Body 2.8 times as long as wide, strongly vaulted. Head twice as wide as long; front notched between pair of oblique frontal ridges; with pair of submedian longitudinal ridges, sharp anteriorly and wider posteriorly; pair of bosses separated from anterior and submedian ridges by curved grooves; with sublateral and lateral ridges above eye; eye sitting on marginal ridge; maxillipedal segment with transverse ridge. Pereonites 1–7 each with median Vshaped elevation, depressed medially and directed posteriorly, largest on pereonites 2 and 3; each with continuous longitudinal sublateral and lateral ridges, slightly produced posteriorly. Coxal plates 1–7 each tapering posteriorly, in contact, each with lateral ridge; plates 2–7 with suture visible only from lateral view between lateral tergal and coxal ridges. Pleotelson one third body length, broadest anteriorly, tapering over posterior third to triangular apex, with elevated median plate defined by sublateral ridges and by a median ridge; pleonites 1 and 2 free and articulating; pleonite 3 suture visible ventrally and dorsally over lateral thirds.

Antennule flagellum a single article almost completely sunk into end of peduncle, with several aesthetascs. Antenna peduncle article 3 almost length of first 2 combined; article 5 twice as long as article 4; flagellum of 7 articles, half length of peduncle. Mandibular incisor 6- or 7-toothed, narrow; left lacinia mobilis 5-toothed, slightly narrow than incisor; right lacinia mobilis irregularly toothed; spine row with up to 12 spines; molar process rounded, setose, without ridges or spines. Maxillule inner lobe with 3 distal plumose setae, outer lobe with 8 apical spiniform setae. Maxilliped operculiform, surrounded anteriorly by ridge-like labrum; endite with 1 or 2 coupling hooks, apically with 7 plumose setae; 3 plumose setae on anterior face; 1 plumose seta at lateral base of palp; palp about twice as long as greatest width; articles 2–3 and 4–5 fused; epipod ovoid; all articles covered with dense mat of cuticular setae.

Pereopod 1 shortest; ischium–carpus without long setae; propodus with field of c. 22 pectinate setae on mesial face. Pereopods 2–7 ambulatory, increasing in length posteriorly, articles more or less cylindrical. Pleopods 1–3 rami with setose margins; pleopod 1 narrow, half length of pleopod 2; pleopods 4, 5 rami without long marginal setae. Uropods and pleopodal cavity reaching to near apex of pleotelson, about half as wide as pleotelson. Uropodal endopod tapering to rounded apex, about third as long as peduncle; exopod oval, less than half length of endopod, with 6 marginal setae.

Ovigerous female with lamellar oostegites on pereopods 1–5.

Colour. Greyish in alcohol.

Remarks. Chilton’s (1885a; b) holotype is longer (10.3 mm) than the specimens figured here. The sculpture pattern described by him is identical to that of the newer material but his figure is more stylised.

Figures

FIGURE 1. Takereana festiva (Chilton, 1885). Ovigerous female, Island Bay, Wellington, NIWA Z 15016. a, b, dorsal and lateral views. c, antennal flagellum.