Parakonarus oregmus, Bamber, 2013

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 : 19-23

Parakonarus oregmus sp. nov.

Figs. 7–9

Pseudoleptochelia fairgo Bamber, 2008 , 205, non- Pseudoleptochelia fairgo Bamber, 2005 .

Type material: One female with brood-pouch, holotype ( QM-W29179 ), 216 females (three brooding), paratypes ( QM-W28142 ), one female with brood-pouch, one neuter (dissected), paratypes ex- QM-W 28142 (not retained): coarse sand and shell with Branchiostoma, Moreton Bay , 27°27.0'S, 153°18.8'E, 8.4–9.9 m, 35 ‰, 29.4°C, 10.02.2005, spanner-crab dredge. 32 females (two brooding), paratypes ( QM-W28145 ), muddy sand with fine shell breccia, Moreton Bay , 27°28.66'S, 153°21.34'E, 7.2 m, 35 ‰, 29°C, 1.02.2005; all van Veen grab, coll. RNB. Two females, paratypes ( BMNH 2006.1650 – 1651 ), sand, north of Banana Bank, Moreton Bay, 27°32.02'S, 153°20.67'E, 4.9m, 35 ‰, 28.8°C, 11.02.2005; van Veen grab, coll. PJFD .

Other material: QM-W28143 , seven females (one brooding), amongst Halophila decipiens on slightly anoxic sand, NE of Chain Banks, Moreton Bay, 27°24.59'S, 153°21.68'E, 7.7 m, 35 ‰, 29.4°C, 10.02.2005, van Veen grab . QM-W28144 , two females with oostegites, amongst Halophila decipiens on slightly anoxic sand, NE of Chain Banks, Moreton Bay, 27°24.58'S, 153°21.75'E, 7.7–8.5 m, 35 ‰, 28.8°C, 11.02.2005, spanner-crab dredge. One damaged female without oostegites, amongst Halophila decipiens on sand with some shell, west side of Moreton Island , Moreton Bay , 27°16.90'S, 153°23.20'E, 4.7 m, 35 ‰, 28.6°C, 10.02.2005, van Veen grab. QM- W28146, two females (one brooding), medium muddy sand with shell, NE of Banana Bank, Moreton Bay, 27°32.53'S, 153°20.99'E, 4.2 m, 35 ‰, 28.8°C, 11.02.2005; van Veen grab . QM-W28147 , two females, sandy mud with seagrass, Banana Bank , Moreton Bay, 27°32.46'S, 153°20.74'E, 3.1 m, 33 ‰, 28°C, 17.02.2005, van Veen grab, all RNB . QM-W28451 , six females , MBWS Stn. 10, 27°31.68'S, 153°20.54'E, 7.6 m, 18.02.2005, van Veen grab , PJFD.

Etymology. From the Greek oregma —a stretching out, relating to the unusually elongate fourth and fifth pereonites of the present species.

Description of female. Holotype body ( Fig. 7A ) 3.0 mm long, 7.8 times as long as wide. Cephalothorax elongate, subrectangular but with convex margins narrowing towards anterior, 1.25 times as long as wide, longer than pereonites 1 and 2 together, with slight rounded rostrum, rounded eyelobes conspicuous, eyes present and black, two lateral setae at posterior of each eyelobe; dorsal cuticular lines distinguishing carapace plates of second thoracomere at posterior of cephalon. Pereonite 1 shortest, with single anterolateral setae, other pereonites naked; pereonite 2 1.6 times as long as pereonite 1, pereonites 3 and 6 subequal, twice as long as pereonite 1, pereonites 4 and 5 subequal, longer than wide, three times as long as pereonite 1; pereonites 1 to 6 respectively 2.7, 1.7, 1.3, 0.9, 0.9 and 1.3 times as wide as long. Each pleonite about 4.4 times as wide as long. Pleotelson semicircular, onequarter length of whole pleon, twice as wide as long, with paired laterodistal and two fine distal setae.

Antennule ( Fig. 7B ) of three articles, without distal cap-like segment; proximal article tumid, twice as long as wide, 1.6 times as long as distal two articles together, with one long and one shorter distal outer simple setae, single medial inner and outer simple setae, and median and distal outer tufts of penicillate setae; second article longer than wide and 0.4 times as long as first article, distal setae much shorter than article; third article three times as long as wide and 0.6 times as long as second article, with seven simple distal setae and one aesthetasc.

Antenna ( Fig. 7C ) proximal article compact, naked; second article 2.3 times as long as first, 1.4 times as long as wide, with fine ventrodistal seta, longer dorsodistal seta and dorsal margin fringed with setules; third article 1.3 times as long as wide, 0.8 times as long as second article, with single dorsal distal seta and fringe of setules along dorsal margin; fourth article longest, 1.8 times as long as second article and 3.7 times as long as wide, with paired setae at mid-length and five distal setae; fifth article as long as third and with three distal simple setae; sixth article minute, with five distal setae.

Labrum ( Fig. 7D ) lobate, distally setose. Left mandible ( Fig. 7E ) with crenulate lacinia mobilis, distally bifid pars incisiva, pars molaris truncate, blunt, with some distal rugosity; right mandible ( Fig. 7F ) similar but without lacinia mobilis, pars incisiva not crenulate, tip slightly bifid. Labium ( Fig. 7G ) wide, bilobate, distally finely setose. Maxillule ( Fig. 7H ) with nine distal spines, distally setose outer and mesial margin; palp distinct, with two distal setae. Maxilla not seen. Maxilliped ( Fig. 7I ) 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 seven setae and submarginal row of three setae; fourth article with distal row of six simple setae and one inner and one outer subdistal seta; basis with five distal setae, middle setae longest but not extending to tip of second palp article; each endite ( Fig. 7J ) distally with single outer seta and two elongate spatulate spines, one rounded undistinguished inner tubercle and outer corner setulose. Epignath (not figured) typical for the subfamily, elongate, slender, setose.

Cheliped ( Fig. 8A, B ) stout; coxal sclerite with two outer setae; basis 2.2 times as long as wide, with mesial dorsodistal slender seta without tubercle; merus triangular with nine ventral setae; carpus 1.7 times as long as wide, outer margin extended ventrodistally and distally to form cuff around base of propodus, with six fine dorsal marginal setae and one ventral submarginal seta, inner ventral and distal margin with two setae; propodus just longer than wide, outer distal margin extended into apophysis bearing strong seta, inner comb-row of four spines with adjacent microtrichia; fixed finger 0.6 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. 9A ) longer than other pereopods, coxa with long seta; basis curved, 4.3 times as long as wide, with dorsoproximal seta longer than basis width; ischium with two unequal setae; merus 0.4 times as long as basis, with one ventrodistal seta; carpus 1.5 times as long as merus, with five distal setae, longest of which is more than half length of propodus; propodus just 1.3 times as long as carpus, with one ventral and three dorsal subdistal setae; dactylus slender, with dorsoproximal seta not reaching tip of dactylus, curved unguis 1.8 times as long as dactylus, the two together 1.7 times as long as propodus.

Pereopod 2 ( Fig. 9B ) more compact than pereopod 1; coxa with seta; basis 3.3 times as long as wide, with single simple and penicillate dorsoproximal setae; ischium with two unequal setae; merus about one-third as long as basis, naked; carpus 1.2 times as long as merus, with single dorsodistal and ventrodistal setae; propodus 1.2 times as long as carpus, with paired subdistal setae longer than dactylus plus unguis; dactylus with distal seta, and twice as long as unguis, both together 0.6 times as long as propodus. Pereopod 3 as pereopod 2.

Pereopod 4 ( Fig. 9C ) basis stout, 1.5 times as long as wide, naked; ischium compact, with two unequal ventrodistal setae; merus one-third as long as basis, with two ventrodistal tubercle-mounted setae and adjacent rows of microtrichia; carpus 1.4 times as long as merus, with one ventrodistal and single outer and inner distal molariform spines and ventral rows of microtrichia; propodus just shorter than carpus, with paired ventrodistal spines and three dorsodistal setae, two of which are longer than dactylus plus unguis; dactylus and minute unguis not fused into an claw, curved, 0.65 times as long as propodus; dactylus with fine dorsal seta. Pereopod 5 as pereopod 4. Pereopod 6 ( Fig. 9D ) similar to pereopod 4, basis with two mid-dorsal penicillate setae, carpus with inner (and outer?) single distal setae; propodus with two longer dorsodistal setae, one shorter simple seta and three shorter bipinnate distal setae.

Pleopods ( Fig. 9E ) all alike, with single dorsal plumose seta on basis; all setae on rami plumose; endopod with single inner plumose seta; proximal outer seta on exopod slightly separated from others.

Uropod ( Fig. 9F ) basis naked; exopod of one segment, longer than proximal endopod segment, outer distal seta longer than inner distal seta; endopod of four segments, third and fourth segments longer than others.

Male unknown.

Remarks. The demarcation of plates in the carapace of Parakonarus oregmus sp. nov. is exactly as found in the generotype, P. kopure (and the other species in this genus). In addition, the setose tubercles on the meri of the posterior pereopods, the paired setae on the ischia of all pereopods, and the dorsal-marginal setae on the cheliped carpus and the one-segmented uropod exopod all accord with Parakonarus . However, the outer-distal seta on the cheliped basis is not mounted on a tubercle, and no discernible cap-like flagellar segment was found on the antennule. Parakonarus oregmus is also unusual in the genus (and family) in being rather elongate, with pereonites 4 and 5 longer than wide (they are as long as wide in P. fairgo , shorter in all other species); the present species is also unique in having short ungues on pereopods 2 and 3 (half as long as the dactylus, “compared” with subequal in length in the other species), and a proximal seta on the dactylus of pereopod 1 (apparently absent in other Parakonarus , present in Konarus spp. ).

Figures

FIGURE 7. Parakonarus oregmus sp. nov., female. A. holotype, dorsal; B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible; G, labium; H, maxillule; I, maxilliped; J, maxilliped endites. Scale line = 1.0 mm for A, 0.2 mm for B to I, 0.1 mm for J.

FIGURE 8. Parakonarus oregmus sp. nov., female. A, right cheliped; B, left cheliped. Scale line = 0.2 mm.

FIGURE 9. Parakonarus oregmus sp. nov., female. A, pereopod 1; B, pereopod 2; C, pereopod 4; D, pereopod 6; E, pleopod; F, uropod. Scale line = 0.2 mm.