Paratouphapleura aaroni George 2021, gen. et sp. nov.

Paratouphapleura aaroni gen. et sp. nov.

urn:lsid:zoobank.org:act: 6F7C1F0C-7A6F-473A-B5B4-78859FE44D59

Figs 8–14; Table 2

The epitheton aaroni is given in fond dedication to my brother, Mr Aaron Martin George (Münster/ Selters, Germany).

3 ♀♀, 3 ♂♂, collected during research cruise ANT-XIX/4 (ANDEEP II) of RV POLARSTERN in 2002.

Holotype ANTARCTICA • ♀; Weddell Sea, E of Antarctic Peninsula; station #133; 65°20.30' S / 54°14.67' W; depth 1109.6 m (locus typicus); multiple corer; SMF 37270/1, on 1 slide.

Paratypes ANTARCTICA • 2♀♀, 3 ♂♂; same collection data as for holotype; SMF 37271/1 (♂ paratype 1/allotype, on 1 slide), SMF 37272/1 (♀ paratype 2, on 1 slide), SMF 37273/1–9 (♀ paratype 3, on 9 slides), SMF 37274/1–8 (♂ paratype 4, on 8 slides), SMF 37275/1 (♂ paratype 5, on 1 slide).

Female

HABITUS (Fig. 8A). Elongate, cylindrical; body length including FR: 493 µm (holotype), 562 µm (paratype 2), 515 µm (paratype 3). Podoplean boundary between pro- and urosoma inconspicuous. Cphth about ⅓ of total body length, with some sensilla and long tube pores laterally and dorsally, and with anterior cephalothoracic setulose tufts (ACST). Cephalic front produced into a moderate peak, from which the A1 arises. Without frontolateral horns (FLH), but cephalothoracic anterior lateroventral processes (CLVPa) weakly developed, ending in long tube pore; sensilla not discernible. Cphth additionally with 3 pairs of tube pores, two of which located dorsally, the third laterally. Cephalothoracic posterior lateroventral processes (CLVPp) (Fig. 9B) long and jet-wing-like, with 1 sensillum halfway on anterior margin and 1 sensillum on its tip. Rostrum (Fig. 9A) small, broader than long, fused to cephalothorax; with pair of sensilla, 1 tube pore, paired membranous projections, and rostral setulose tuft (RST). P2–P4-bearing thoracic somites (Fig. 8A) dorsally with 1 tube pore and paired unarmoured small cuticular processes (DP1–DP3), each carrying a sensillum at its tip; laterally with thoracic setulose tufts TST1–TST3. Following body somites without cuticular processes. P5-bearing somite dorsally with tube pore and 2 sensilla. GDS dorsally with fine suture indicating former separation; anterior part of GDS dorsally with 1 tube pore, laterally with setulose tufts (GST) accompanied by 1 tube pore; posterior part of GDS as well as subsequent abdominal somite dorsally with 2 tube pores and 2 sensilla on posterior margin, which in addition presents a row of spinules; laterally with abdominal lateral setulose tufts AST1 and AST2, each accompanied by 1 tube pore. Penultimate abdominal somite dorsally with spinulose posterior margin and with AST3 (only discernible on the right side in Fig. 8A) but without sensilla and tube pores. Telson half as long as previous somite, slightly trapezoidal, with AST4 and spinulose anal operculum flanked by 2 sensilla.

FR (Figs 8A, 9C). Diverging, rami slender, about 3.5 times as long as broad and as long as telson and preceding somite together, with 1 small tube pore proximally on outer margin and bearing 7 bare setae (Fig. 9C): setae I and II of almost the same length, inserting halfway on outer margin and set close together, I bipinnate, II bare; III bipinnate, inserting subapically on outer margin; setae IV and V located apically, IV bare, visibly smaller than III, V longest element, bipinnate; VI bare, even smaller than IV, inserting apically on inner margin; VII bare, tri-articulate, arising dorsally from small knob.

A1 (Fig. 10A). Partly or completely broken in all three females. Most complete condition present in holotype: slender, 4-segmented, first and third segments of almost the same size, about twice as long as second and fourth segment. First and second segments with several long spinules, following segments without spinulose ornamentation. First segment with biplumose seta subapically; second segment with 8 setae (5 broken); third segment with 8 setae (2 broken), 2 of which forming acrothek together with aes; fourth segment with 3 lateral setae; apically with at least 5 setae; acrothek that might consist of 2 additional setae and aes broken, not discernible.

Armature formula: I–1; II–8; III–6(+ 2 + aes), IV–8(+2? + aes?).

A2 (Fig. 11A). Without exp. Allobasis with row of spinules and 2 abexopodal bipinnate setae. Endopod laterally with few spinules, on distal half with 2 well-developed bipinnate setae, third small bare seta absent. Apically with 4 long geniculate setae and 1 smaller seta, all bare, and with spinulose frill.

MD (Fig. 11B). Gnathobase apically with 2 multicuspidate teeth; palp unilobed, with some fine, long spinules, and with 2 lateral (basal), 3 apical (endopodal), and 1 outer (exopodal) setae, all biplumose.

MXL (Fig. 11C). Praecoxal arthrite with set of spinules, apically with 6 spines and on each edge with 1 seta; additionally, with 2 surface setae; all elements bare. Coxal endite apically with 1 bare seta. Basis, endopod and exopod fused to single lobe, carrying 4 lateral setae, the proximal one bipinnate, the remaining three bare; apically with 3 bare setae and 2 unipinnate spines.

MX (Fig. 11D). Syncoxa and allobasis separated; syncoxa apically with cluster of spinules, and with 2 endites; proximal endite with 1 strong bipinnate spine, fused to segment, and with 2 bare setae; distal endite with bare spine fused to the segment, and with 2 bare setae. Allobasis with 1 claw-like element fused to the segment; additionally, with 2 bare setae. Endopod 1-segmented, small, with 2 bare setae.

MXP (Fig. 11E). Prehensile, syncoxa without spinules but with 1 biplumose seta on apical edge; basis with 2 rows of long spinules; endopod produced into long bare claw, basally accompanied by 1 tiny seta.

P1 (Fig. 10B). With transversely elongated basis and 2-segmented exo- and endopod. Praecoxa small, triangular; coxa small, more or less rectangular. Basis with several long spinules on anterior margin, and with 1 inner and 1 outer element (broken in Fig. 10B). Exopodal segments of nearly the same size, exp- 1 with row of spinules on outer distal margin, and with 1 outer bipinnate seta; exp-2 without spinules, with 1 bipinnate outer seta, and (sub)apically with 4 geniculate elements, all with row of pinnules previous to geniculation.

P2–P4 (Fig. 12A–G). With slender, bow-like intercoxal sclerites (P3: Fig. 12F; P 4: Fig. 12G) and transversely elongated bases that carry long spinules and 1 tube pore on their anterior margins, as shown for P2 (Fig. 12A). Exp-1 with few spinules on inner and/or outer margin, posteriorly with 1 bipinnate spine; exp-2 also with few spinules as depicted, and with 1 inner biplumose seta and 1 bipinnate outer spine; exp-3 with 2 outer bipinnate elements, short and spine-like in P2 but long and seta-like in P3 and P4; additionally, with 2 apical biplumose setae; inner margin of exp-3 with 1 biplumose seta in P2 and P4, but with 2 biplumose setae in P3. Endopods small and 2-segmented, enp-1 shorter than enp-2, without ornamentation; P2 enp-2 with few spinules and 2 apical setae, outermost pinnate on the outer but plumose on the inner margin, innermost seta biplumose and not reaching half the length of the outer one; enp-2 of P3 and P4 each with 2 biplumose apical setae, and with 1 outer bipinnate seta reaching at most ⅓ (P3) or half (P4) the length of the apical elements. Setation of P2–P4 as in Table 2.

P5 (Fig. 13A). Baseoendopod and exopod distinct. Baseoendopod with outer bipinnate seta arising from long slender setophore (broken in Fig. 13A) and accompanied by 1 long tube pore and long spinules. Endopodal lobe minute, with 1 long bipinnate seta on its distal part, and with 1 tube pore. Exopodal lobe slightly longer than baseoendopod, with 2 outer, 1 subapical, and 2 apical bipinnate setae; subapically with long tube pore.

GF (Fig. 9D). With single gonopore; P6 not forming genital operculum; lobes strongly reduced, each ending in a small bare seta (1 seta broken in Fig. 9D).

Male

The male (Fig. 8B) resembles the female in most characters. Sexual dimorphism consists of a slightly smaller body size (allotype: 410 µm, paratype 4: 417 µm, paratype 5: 459 µm), smaller dorsal cuticular processes DP1–DP3, the A1, the P3 endopod, the P5, and the absence of a P6.

A1 (Fig. 14A). 7-segmented, subchirocer. First segment with long spinules on surface and anterior margin, and with 1 seta apically (broken in Fig. 14A); second segment as long as first, with 8 bare setae (two of which broken in Fig. 14A); third segment small, almost triangular, with 4 bare setae; fifth segment minute, with 2 small bare setae; sixth segment swollen, setation not discernible because of position on the slide and the risk of breaking the A1 if it is turned (its description is therefore postponed until additional material is found) sixth segment small and squarish, without ornamentation; seventh segment twice as long as sixth, tapering posteriorly, with 9 bare setae, 2 of which form an apical acrothek together with 1 aes.

P3 ENDOPOD (Fig. 14B). 3-segmented, first segment small and unarmed, second segment about three times as long as first, ending in acute apophysis; third segment slightly shorter and narrower than first, not reaching end of apophysis, with 2 long biplumose setae apically.

P5 (Fig. 13B). Exopod separated from baseoendopod, with several long spinules and 2 outer and 2 apical bipinnate setae; additionally, with 1 subapical bare seta but without tube pore; baseoendopod as in female but endopodal lobe smaller, likewise the single endopodal seta, which is small and bare.