Pseudoleptochelia anomala ( Sars, 1882 )

BAMBER, ROGER N, 2013, A re-assessment of Konarus Bamber, 2006 and sympatric leptocheliids from Australasia, and of Pseudoleptochelia Lang, 1973 (Crustacea: Peracarida: Tanaidacea), Zootaxa 3694 (1), pp. 1-39 : 29-35

Pseudoleptochelia anomala ( Sars, 1882)

Figs 13–16

Heterotanais anomalus Sars, 1882 , 30–31; Sars 1886, 333–337, Pl. 13; Smith, 1906, 336, Pl. 21 figs 29–35.

H. algiricus Dollfus, 1898 , 38–39, Fig. 3.

H. magnus Smith, 1906 , 336–337, Pl. 21 figs 36–39.

Pseudoleptochelia anomala Riggio, 1996 , 874, figs 32–34 (male only).

Material. Voucher specimens: one male, one female ( BMNH 2013.2217 ), sample 29 ; seven females, one neuter ( BMNH 2013.218 - 225 ), sample 17 ; two females, two neuters ( BMNH 2013.226 - 229 ), sample 6 ; two females ( BMNH 2013.230 - 231 ), sample 10. Dissected specimens (retained by the author) : one male, two females, sample 4; one male, sample 25; two females, sample 20. Other material: twenty further specimens (males and females), retained. All Balearic Islands, ca 39°28′N 03°30′E, infralittoral algae, coll. Toni Box , 2009.

Description of female. Body ( Fig. 13A ) small for a leptocheliid, figured specimen 1.7 mm long, 5.4 times as long as wide. Cephalothorax subrectangular but with convex margins, 1.2 times as long as wide, longer than pereonites 1 to 3 together, with slight rounded rostrum, rounded eyelobes conspicuous, eyes present and black, one lateral seta at posterior of each eyelobe; faint dorsal cuticular line distinguishing second thoracomere at posterior of cephalon hardly expressed. Pereonite 1 shortest, with single anterolateral setae; pereonites 2 to 6 and pleonites with single lateral setae (anterior on pereonites) and single dorso-lateral setae on each side; pereonite 2 just longer than pereonite 1, pereonites 3 and 6 subequal, 1.8 times as long as pereonite 1, pereonites 4 and 5 subequal, about 2.5 times as long as pereonite 1; all pereonites wider than long (respectively 3.8, 2.5, 2.1, 1.7, 1.4 and 2.1 times as wide as long). Each pleonite about 3.6 times as wide as long. Pleotelson semicircular, just longer than fifth pleonite, twice as wide as long, with paired laterodistal and two fine distal setae.

Antennule ( Fig. 13B ) of three articles, proximal article tumid, 1.9 times as long as wide, 1.5 times as long as distal two articles together, with one long and one shorter distal outer simple setae and single medial and distal outer penicillate setae, inner margin with two simple and two penicillate medial setae; second article longer than wide and 0.3 times as long as first article, distal setae shorter than article; third article 2.4 times as long as wide and 1.2 times as long as second article, with four simple distal setae and one aesthetasc.

Antenna ( Fig. 13C ) proximal article compact, naked; second article 1.3 times as long as first, wider than long, with fine ventrodistal seta, longer dorsodistal seta and narrow dorsal flange; third article about as long as wide, 0.8 times as long as second article, with single dorsal distal seta; fourth article longest, twice as long as second article and 2.5 times as long as wide, without seta at mid-length; fifth article as long as third and with one distal simple seta; sixth article minute, with six distal setae.

Labrum ( Fig. 13D ) lobate, distally setose. Left mandible ( Fig. 13F ) with smooth lacinia mobilis, no crenulation on pars incisiva, pars molaris elongate, blunt, with some distal rugosity; right mandible ( Fig. 13E ) similar but without lacinia mobilis, pars incisiva finely crenulate, tip bifid. Labium ( Fig. 13G ) wide, bilobate, distally finely setose. Maxillule ( Fig. 13H ) with nine distal spines, setose outer margin; palp distinct, with two distal setae. Maxilla not seen. Maxilliped ( Fig. 13I ) palp first article naked, second article with one outer and four inner setae, distal-most inner seta almost reaching distal margin of third palp article; third article with inner row of five setae, fourth article with inner to distal row of five simple setae and one subdistal seta; basis with three distal setae, outer setae longest and extending to tip of second palp article; each endite distally with single outer seta and two elongate spatulate and one rounded spines. Epignath ( Fig. 13J ) elongate, slender, setose.

Cheliped ( Fig. 14A, B ) stout; coxal sclerite with two outer setae; basis 2.1 times as long as wide, with mesial dorsodistal slender tubercle bearing seta; merus triangular with seven ventral setae; carpus 1.6 times as long as wide, outer margin extended ventrodistally and distally to form small cuff around base of propodus, with four fine dorsal marginal setae and one ventral submarginal seta, inner ventral and distal margin with two setae; propodus about as long as wide, outer distal margin extended into apophysis bearing strong seta, inner comb-row of three spines with adjacent microtrichia; fixed finger 0.8 times as long as propodus, with two ventral setae and three inner setae, cutting edge crenulate, terminal spine subdistal; dactylus simple with proximal seta less than half as long as dactylus.

Pereopod 1 ( Fig. 14C ) longer than other pereopods, coxa with long seta; basis curved, three times as long as wide, with dorsoproximal seta shorter than basis width; ischium with two setae; merus about half as long as basis, naked; carpus 1.9 times as long as merus, with four distal setae, longest of which is less than half length of propodus; propodus just longer than carpus, with one ventral and three dorsal subdistal setae; dactylus slender, with dorsoproximal seta not reaching tip of dactylus, curved unguis 2.2 times as long as dactylus, the two together 1.3 times as long as propodus.

Pereopod 2 ( Fig. 14D ) more compact than pereopod 1; basis 2.5 times as long as wide, with dorsoproximal seta; ischium with two setae; merus about one-third as long as basis, naked; carpus just longer than merus, with two ventrodistal setae; propodus 1.4 times as long as carpus, with dorsal subdistal seta as long as dactylus; dactylus with proximal seta, and longer than unguis, both together as long as propodus. Pereopod 3 ( Fig. 14E ) similar to pereopod 2, but propodus with small ventrodistal spine, longest dorsodistal seta longer than dactylus.

Pereopod 4 ( Fig. 14F ) basis stout, 1.8 times as long as wide, naked; ischium compact, with two ventrodistal setae; merus 0.3 times as long as basis, with two ventrodistal tubercle-mounted setae; carpus with one ventrodistal and paired outer and inner distal molariform spines and ventral microtrichia; propodus just longer than carpus, with paired (?) ventrodistal molariform spines and three dorsodistal setae, two of which are as long as dactylus plus unguis; dactylus and unguis fused into a claw, curved. Pereopod 5 as pereopod 4. Pereopod 6 ( Fig. 14G ) as pereopod 4, merus with paired ventrodistal molariform spines and no setae; propodus with seven dorsodistal setae.

Pleopods ( Fig. 14H ) all alike, with single dorsal plumose seta on basis; all setae on rami plumose; endopod with single inner plumose seta; proximal outer seta on each ramus slightly separated from others.

Uropod ( Fig. 14J ) basis naked; exopod of two segments, although articulation line often obscure, just longer than proximal endopod segment, outer distal seta longer than inner distal seta; endopod of five segments, third segment longer than others.

Description of neuter: Generally a smaller version of female, uropod ( Fig. 14I ) exopod and endopod articulation not evident, endopod apparently of four segments.

Description of male. Slightly smaller than female, body length ( Fig. 15A ) 1.5 mm, 5.8 times as long as wide, cephalon about as long as pereonites 1–3, with large eyelobes bearing large black eyes; pereonite 1 shortest, pereonites 2, 3 and 6 subequal, 1.4 times as long as pereonite 1; pereonites 4 and 5 longest, twice as long as pereonite 1. Pleonites subequal in length, 0.9 times as long as pereonite 1, pleotelson just longer than pleonite 5. Sexual dimorphism as follows.

Antennule ( Fig. 15B ) elongate, first peduncle article 1.4 times as long as wide with dorsodistal seta shorter than article width; second article 0.85 times as long as first with single ventrodistal and dorsal subdistal setae shorter than article width; third article short, with ventral seta; flagellum of 10 segments, first segment with proximal row of 15 and distal row of 17 aesthetascs; second to eighth segments with distal rows of 17, 20, 20, 15. 10, 7 and 4 aesthetascs respectively; ninth segment with two distal setae, distal segment with five setae. Antenna ( Fig. 15C ) more slender than that of female, second article without flange, fifth article as long as fourth. Mouthparts atrophied.

Cheliped ( Fig. 16A ) merus with five or six ventral setae; carpus with setae along dorsal margin, no distal cuff, no ventral apophysis; chela subchelate, propodus 1.6 times as long as wide, with comb-row of eleven spines, without ventral or distal apophyses; fixed finger 0.2 times as long as palm and one-quarter as long as dactylus; dactylus with proximal seta and short spinules along cutting edge.

Pereopods ( Fig. 16B–G ) more slender than those of female, pereopod 1 ( Fig. 16B ) basis 5.5 times as long as wide, dactylus plus longer unguis together just shorter than propodus. Posterior dactyli with dactylus and unguis not fused, dactylus without distal setules.

Setae of pleopod rami ( Fig. 15D ) slightly longer than those of female. Uropods ( Fig. 15E–G ) similar to those of female, with one longer distal seta; articulation lines often obscure.

Remarks. While P. anomala is clearly a member of the Konariinae as defined here, it has sufficient distinguishing characters (demarcation of second thoracomere hardly expressed; shorter setae on basis, propodus and dactylus of pereopod 1; antennal article 4 without seta at mid-length in female; left mandible with no crenulation on lacinia mobilis or pars incisiva; maxilliped basis with only three distal setae) or confusing characters (tubercle-mounted setae on the meri of pereopods 4 and 5—as in Parakonarus —but not on pereopod 6—as in Konarus ; no antennular flagellum and a two-segmented uropod exopod—as in Konarus —but two setae on the ischium of pereopod 1, and a setose dorsal margin to cheliped carpus—as in Parakonarus ), that it falls into a separate genus from Konarus and Parakonarus .

The unusual feature of an elongate third uropod-endopod segment, although variable in males, is consistent in the present material, and was also shown clearly by Sars (1986); this is thought likely to be a species-specific character, rather than a generic feature. Some species of Parakonarus ( P. kopure , P. sozo ) also have an elongate third or fourth uropod segment. Unlike the other two konariin genera, the distinction of plates in the cephalon is not expressed; the faint line at this point on the carapace was not shown at all in neuters, and very hard to see in adults, where in fact it may have been an artefact.

Figures

FIGURE 3. Konarus straddi comb. nov., A, female, dorsal, with A′, detail of carapace margin; B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible; G, labium; H, maxillule; I, maxilliped; J, epignath. Scale line = 1.0 mm for A, 0.2 mm for B to J.

FIGURE 13. Pseudoleptochelia anomala, female. A, habitus, dorsal; B, antennule; C, antenna; D, labrum; E, right mandible; F, left mandible; G, labium; H, maxillule; I, maxilliped and endite; J, epignath. Scale line = 1.0 mm for A, 0.2 mm for B to J.

FIGURE 14. Pseudoleptochelia anomala, female. A, left cheliped; B, same, inner face of chela; C to F, pereopods 1 to 4; G, pereopod 6; H. pleopod (most setae represented by their bases only); I, uropod of neuter; J, uropod of brooding female. Scale line = 0.2 mm.

FIGURE 15. Pseudoleptochelia anomala, male. A, habitus, dorsal; B, antennule (most aesthetascs represented by their bases only); C, antenna; D, pleopod (most setae represented by their bases only); E, uropod of 1.6 mm male; F, right and G, left uropods (ventral) of 1.8 mm male. Scale line = 0.8 mm for A, 0.2 mm for B to G.

FIGURE 16. Pseudoleptochelia anomala, male. A, right cheliped; B to G, pereopods 1 to 6 respectively. Scale line = 0.2 mm.