Paratanais tara, Bird, 2011

BIRD, GRAHAM J., 2011, Paratanaoidean tanaidaceans (Crustacea: Peracarida) from littoral and shallow sublittoral habitats in New Zealand, with descriptions of three new genera and seven new species, Zootaxa 2891 (1), pp. 1-62 : 26-34

Paratanais tara n. sp.

Figs 12–17

Material examined. All from north or west coasts of North Island , New Zealand. Holotype: neuter/non-ovigerous female, 3.0 mm, GJB/2-05 lower eulittoral, algal turf and other encrusting biota, New Plymouth Aquatic Centre , 20/8/2005, [CR.21772]. Allotype: swimming male, 2.2 mm, GJB/7-10, LWN rock with piddock borings, Maukutea Beach, Aotea Harbour, 8/4/2010, [CR.21773]. Paratypes: two manca-II, one manca-III, four neuters [one partly dissected on microslide CR.21777], GJB/1-05, [CR.21776]; two manca-II, seven neuters, one ov. female, one male [partly dissected on microslide CR.21775], GJB/7-10, [CR21774]; one manca-II, seven neuters [one partially dissected] GJB/2-05, [ NIWA: 70535]. Other material: three neuters, GJB/2-10; one neuter, GJB/4-10; one manca-II, GJB/5-10; one neuter, NZOI BS-241 , [CR.21806]; one neuter, NZOI BS-794 , [CR.21807] .

Diagnosis. Female: Paratanais with pleon as long as pereonites 5–6; plumose setae on pleonites 1–4 only. Antenna article-2 with inferior thorn-like apophysis. Mandible lacinia mobilis with crenulated distal margin. Maxilliped palp article-2 with only one unspecialised pinnate seta (i.e. similar to those on articles 3–4); endite with strong medial seta. Cheliped propodus with seta near articulation with dactylus; dactylus with two inferior spines. Pereopod-1 merus 2.5 times ltb. Pereopods 4–6 carpal spines well-developed. Uropod as long as pleotelson, exopod 1-segmented.

Male: Habitus paratanaid swimming form. Cephalothorax shorter than pereonites 1–3. Pereonites 4-6 longer than pereonites 1-3 and pleonites. Antennule peduncle 3-articled, article-1 twice as long as broad; flagellum 5-segmented, with terminal segment cap-like. Antenna article-2 similar to female. Cheliped fixed finger incisive margin smooth but uneven; dactylus with two digitiform spines. Uropod endopod 3-segmented, slender.

Etymology. From Te reo Māori noun tara , ‘a thorn’, alluding to the inferior spine on antenna article-2.

Type locality. Lower eulittoral rocky-shore adjacent to Aquatic Centre , New Plymouth, North Island, New Zealand; specifically, ca. 39° 03´16´´S 174° 03´47´´E (sourced from Google Earth) .

Description. Neuter: Habitus ( Figs 12A , 15H ) typical paratanaid, unpigmented, cuticle pale and shiny; slen- der, up to 7.5 times ltb, length 1.47–3.65 mm. Cephalothorax pear-shaped, 1.3 times ltb, almost as long as pereonites 1–2 combined; lateral margin with small setae posterior to eyes and at mid-length. Pereon 57% of body length, pereonite-1 shortest, pereonites 2–5 of similar length, with almost straight lateral margins; all pereonites shorter than broad, 0.43, 0.78, 0.77, 0.79, 0.82 and 0.68 times as long as broad respectively; pereonite-1 with four distolateral and distomedial setae, pereonites 2–6 with two distolateral setae. Pleon ( Fig. 12B ) as long as pereonites 5 and 6, 18% of body length, 1.5 times ltb; pleonite-5 slightly longer than rest; pleonites 1–4 with one large circumplumose seta on epimeral margin, pleonites 1–3 also with a simple seta. Pleotelson ( Fig. 12C ) as long as pleonites 4–5, about half as long as broad, with two posteriolateral setae, weakly rounded posterior margin (dorsal view) with four simple setae and two PSS, and with small deflexed apex bearing two setae ( Fig. 12D ).

Antennule ( Fig. 12F ) 0.8 times as long as cephalothorax; article-1 about 50% of total length, twice as long as broad, lateral margin with proximal and distal groups of PSS and one distal simple seta, mesial margin with small distal seta; article-2 just shorter than broad, with long lateral seta and three PSS, with small inferior seta; article-3 0.75 times as long as article-2, as long as broad, with one mesial and one lateral distal setae; article-4 just shorter than articles 2–3 together, with distal seta; article-5 tiny, cap-like, with five setae and one aesthetasc. Antenna ( Figs 12G , 15J, L–M ) 0.7 times as long as antennule, stout; article-1 simple, short and naked; article-2 large, as long as broad, distally expanded, with setulose superior margin, one superior distal seta and ventrally directed thorn-like inferodistal spine; article-3 half length of article-2, shorter than broad, with strong superior distal spine; article-4 just longer than article-2, 2.3 times ltb, with medial seta, one distal simple and two PSS; article-5 less than half as long as article-4, twice as long as broad, with one distal seta; article-6 short, cap-like, with six long terminal setae and one PSS.

Labrum ( Fig. 13A ) cap-shaped, apically setose. Labium ( Fig. 13B ) lobes rounded, distally setose. Mandible ( Figs 13C–D ) left incisor with crenulated distal margin, inner process largest, lacinia mobilis very broad, with about six processes; right incisor with crenulated distal margin and weakly bifid tip; molar process as large as incisor, of grinding type, with numerous ridges and granular crushing surface. Maxillule ( Fig. 13E ) endite with distal groups of setae and at least eight terminal spines. Maxilla ( Fig. 13F ) subovate, as large as maxilliped palp article-2. tooth-like distal spines and inner seta; palp article-1 naked, article-2 with lateral seta, two simple and one finely pectinate mesial setae; article-3 curved, with one smooth and three pinnate mesial setae; article-4 shorter than article-3, with one distal simple and five terminal pinnate setae. Epignath not recovered. dibles respectively; E maxillule endite; F maxilla; G maxilliped (setation of distal palp articles omitted for clarity); H maxilliped endites, distal; J maxilliped palp articles 3 and 4; K right cheliped; L fixed finger distal; M left chela (mesial view). Scale bar: 0.25 mm.

2–3; D uropod; paratype manca-III: E habitus; F antenna article-2 inferior spine; G uropod; paratype small neuter: H habitus; J antenna articles 2–3; K uropod; Aotea Harbour neuters: L–M antenna article-2 inferior spine variation. Scale bars: (i) 0.125 mm for A; (ii) 0.5 mm for B, E and H, 0.125 mm for C, D, F–L.

Cheliped ( Figs 12H , 13K–M ) coxal sclerite with acuminate posterior extending to cephalothorax margin; basis 1.4 times ltb, with posterior free process smaller than anterior part, latter with lateral seta; merus subtriangular, inferior margin much longer than that of carpus, with one long seta; carpus subovate, longer than basis, 1.7 times ltb, with two unequal inferior setae and two smaller superior setae; propodus as long as but narrower than carpus, 2.3 times ltb, palm slightly narrower distally, almost 3.5 times longer than fixed finger, with seta near dactylus articulation and with mesial comb of three pectinate spines; fixed finger with raised crushing incisive margin, two inferior setae and three setae near incisive margin, terminal spine conical; dactylus basally as wide as fixed finger, with strong mesial seta and two spines on incisive margin.

Pereopod-1 ( Fig. 14A ) coxa with seta; basis curved, slightly narrower than pereopods 2–3, 4.4 times ltb, with proximal seta on slight process; ischium with one seta; merus 2.5 times ltb, with strongly oblique articulation with carpus, naked; carpus two-thirds as long as merus, twice as long as broad, with two unequal superior distal setae, and small mesial and inferodistal setae; propodus narrow, about 1.7 times longer than carpus, 5.5 times ltb, with strong superior distal seta and long inferodistal seta, apex setulated; dactylus shorter than unguis, with proximal seta, together as long as propodus. Pereopod-2 ( Fig. 14B ) stouter than pereopod-1; coxa with long seta; basis 3.25 times ltb (greatest width), with proximal seta; ischium with one seta; merus distally wider, with oblique articulation with carpus, 1.25 times ltb, with inferodistal spine (lateral) and seta (mesial); carpus subrectangular, as long as merus, with one strong superior distal spine (lateral) and small seta (mesial), and two inferodistal spines; propodus about as long as merus and carpus combined, narrower, with one superior distal seta and one longer inferodistal seta, apex setulated; dactylus shorter than unguis, together as long as propodus. Pereopod-3 ( Fig. 14C ) similar to pereopod-2, but basis slightly shorter; dactylus and unguis just shorter than propodus.

Pereopod-4 ( Figs 14D–E ) basis robust, larger than pereopods 1–3, 2.7 times ltb, with proximal seta; ischium with two unequal setae; merus with oblique articulation with carpus, with two strong inferodistal spines; carpus subrectangular, as long as merus, twice as long as broad, inferodistal margin with row of microtrichia, distal margin with four stout bifid (or complex) spines and stiff superior seta (mesial); propodus as long as carpus, superior margin with a PSS, superior distal margin with spine as long as dactylus, and two shorter inferodistal spines, apex setulated; dactylus and unguis claw-like, shorter than propodus. Pereopod-5 ( Fig. 14F ) similar to pereopod-4 but basis midlength with two inferior pinnate setae. Pereopod-6 ( Figs 14G–H ) similar to pereopods 4–5 but propodus without a PSS, with three pectinate superior distal spines.

Pleopod ( Fig. 15A ) peduncle longer than broad, naked; endopod subovate, twice as long as broad, with setulated mesial margin, with one mesial distal plumose seta, lateral margin with 15 plumose setae, with slight gap between most proximal seta and rest; exopod slightly longer and more slender than endopod, with ca. 23 plumose setae on lateral margin, with slight gap between most proximal seta and rest.

Uropod ( Figs 12E , 15K ) just longer than pleotelson; peduncle as long as broad; exopod 1-segmented, slender, seven times ltb, reaching beyond segment-1 of endopod, with two long, unequally thick, terminal setae; endopod 2- segmented, 5.5 times ltb, segment-1 0.6 times total length, with one simple and two distal PSS; article-2 apex with four long, one short simple, and three PSS.

Manca-II: Habitus ( Fig. 15B ) generally similar to neuter but body fairly slender, 5.8 times ltb; length 1.04– 1.23 mm. Cephalothorax proportionately longer. Pereonites 2–4 shorter. Pleonites 1–5 without epimeral plumose seta. Antenna ( Fig. 15C ) article-2 without inferior spine. Uropod ( Fig. 15D ) stouter.

Manca-III: Habitus ( Fig. 15E ) similar to manca-II but more slender, seven times ltb; length 1.34 mm. Cephalothorax proportionately shorter. Pereonites 2–5 longer. Antenna ( Fig. 15F ) article-2 with inferior spine. Uropod more slender than manca-II ( Fig. 15G ).

Ovigerous female: similar to neuter but with oostegites; length 3.84 mm.

Male: Habitus (Fig. 16A): typical of genus, fairly stout, 5.4 times ltb, length 1.97–2.2 mm. Cephalothorax (Fig. 16B) flask-shaped, as long as pereonites 1–3, rostrum spatulate; eyes 0.3 times as long as cephalothorax. Pereon 46 % of body length, all pereonites less than half as long as broad, but pereonites 4–6 clearly longer than pereonites 1–3. Pleon 24% of body length, just shorter than pereonites 4–6, pleonites shorter than pereonites 2–6. Pleotelson: twice as wide as long, setation as in female.

Antennule (Fig. 16C) as long as cephalothorax, with 3-articled peduncle and 5-segmented flagellum; peduncle article-1 about 50% of total length; article-2 with three PSS; article-3 with superior and inferior seta; flagellar segments 1–3 with inferior bundle of aesthetascs (ca. eight, six and four, respectively), segment-4 with distal seta, segment-5 short with several setae and aesthetasc. Antenna (Fig. 16D) similar to female but article-3 less expanded, with superior stiff seta, article-4 more slender, with about three PSS and long distal seta; article-5 more slender.

Mouthparts: reduced (maxilliped present), typical of genus.

Cheliped (Figs 16E, 17A) similar to female but carpus stouter, 1.5 times ltb; propodus palm stouter, 0.67 times length of chela, with mesial comb of ten spines; dactylus stronger mesial seta, and with one seta and two digitiform spines on incisive margin.

Pereopod-1 ( Figs 17B ) similar to female but carpus superior distal seta shorter; propodus superior distal seta weaker; dactylus and unguis shorter, 0.5 times as long as propodus. Pereopod-2 ( Fig. 17C ) similar to female but

Pereopod-4 similar to pereopod-5. Pereopod-5 ( Fig. 17D ) similar to female but basis more slender, with two superior PSS; carpal spines smaller; propodus more slender, as long as carpus and merus together, with a smaller superior PSS, smaller and weaker superior and inferior distal spines; dactylus and unguis longer. Pereopod-6 ( Fig. 17E ) similar to pereopod-5 but propodus without a superior PSS, and with three superior distal pectinate spines.

Pleopod similar to female but exopod and endopod setae proportionately longer.

Uropod (Fig. 16F) just longer than pleotelson; peduncle as long as broad, naked; exopod 2-segmented, slender, reaching half of endopod segment-3, segment-1 with seta, segment-2 with unequal terminal setae; endopod 3-segmented, segment-1 shorter than broad, with a PSS, segment-2 twice as long as segment-1, with simple setae and two PSS, segment-3 as long as previous two combined, with four simple (one very long) and three PSS.

Remarks. Among other described Paratanais species , the prominent inferior spine on antennal article-2 is possessed only by P. gaspodei of Western Australia and the recently described P. martinsi Bamber & Costa, 2009 from the Azores. Of these two, P.tara is closer to the latter in body shape (cephalothorax and pereonite proportions). It differs from P. gaspodei in antennal shape and has, among other things, rounded maxilliped endite teeth, a more slender palp article-2 distal seta, a larger cheliped fixed finger and dactylus (c.f. palm), more complex pereopod setation, and a longer uropod exopod. A phylogenetic study might verify a close affinity of P. tara with these two species and suggest a separate taxonomic status from other Paratanais species. The specimens of P. tara from Aotea Harbour have very slightly different antennal spines ( Fig. 15L ) compared to the New Plymouth material.

Compared to the other NZ Paratanais species (see below) P. tara has a longer pereonite-2 (c.f. pereonite-1) and slightly higher rate of pleon lengthening with size increase. The male is also more elongate in P. tara , with a proportionately smaller cephalothorax; in this respect it also differs from the more compact shape of the males of the Australian species P. maleficus and P. wanga . However, it belongs to the group of species with males having an antennule with three, four or five flagellar segments (e.g. Paratanaidae indet. ( Sieg 1986a), P. clarkae Bird & Bamber, 2000 , and P. maleficus , respectively).

Distribution and ecology. Like Parakonarus kopure , Paratanais tara inhabits the lower littoral rocky shore but it is also found in outer estuarine sands. Sympatric tanaidaceans in rocky shore habitats include Apseudomorpha timaruvia , Metapseudes sp. , Cyclopoapseudes sp. , and Zeuxoides rimuwhero , but with Araphura whakarakaia n. sp. (see below) in muddy sand.

It is known only from the three localities on the west coast of the North Island, between Taranaki and Northland. The specimens from the Northland BS- 241 and BS- 794 stations were recorded as P. oculatus by J. Sieg .

Figures

FIGURE 12. Paratanais tara n. sp. Holotype female: A habitus (pereonite-1 slightly damaged); B pleonite epimera plumose

FIGURE 13. Paratanais tara n. sp. Paratype preparatory female: A labrum (lateral view); B labium; C–D left and right man-

FIGURE 14. Paratanais tara n. sp. Paratype preparatory female: A–C pereopods 1–3 respectively, with inner carpal spines of pereopods 2–3; D pereopod-4; E pereopod-4 carpus lateral setation; F–G pereopods 5–6 respectively; H pereopod-6 distal (lateral view). Scale bar 0.25 mm.

FIGURE 15. Paratanais tara n. sp. Paratype preparatory female: A pleopod; paratype manca-II: B habitus; C antenna articles

FIGURE 17. Paratanais tara n. sp. Allotype swimming male: A cheliped; B pereopod-1; C pereopod-2; D pereopod-5; E pereopod-6 distal (lateral view). Scale bar: 0.125 mm.