Comprehensive Description

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“Bathynomus kapala n. sp.


Bathynomus ?affinis.—Hale, 1940: 292-293, pl. 18. Not Bathynomus aifinis Richardson, 1910.


Holotype. Female, 110 mm (AM P.17947), off Wollongong, 34°24'S., 151°20'E. to 34°29'S., 151°17'E., 351 m, prawn trawl, FRV Kapala, 6 July 1971.


Paratypes. 7 8 8 , 11 9 9 , 82.5-110 mm, all collected by FRV Kapala as follows : off Port Stephens, 32°46'S., 152°46'E. to 32°51'S., 152°42'E., 585-576 m, sandy mud, prawn trawl, 7 July 1971, 1 9 (AM P.17949) ; north of Sydney, 33°41'S., 151°55'E. to 33°44'S., 151°53'E., 540 m, prawn trawl, 20 April 1971, 2 8 (AM P.17948) ; off Broken Bay, 33°34'S., 152°03'E. to 33°43'S., 152°59'E., 558 m, smooth bottom, prawn trawl, 21 April 1971, 1 9 (AM P.18086) ; south-east of Broken Bay, 33°40'S., 151°55'E. to 33°35'S., 151°58'E., 540 m, prawn trawl, 14 July 1971, 1 9 (AM P.17954) ; 40 km east of Sydney, 33°40'S., 151°52'E. to 33044'5., 151°49'E., 270-360 m, 6 April 1971, 1 9 (AM P.18010), 1 d , 1 9 (AM P.17952) ; off Sydney, 33°40'S., 151°53'E. to 33°44'S., 151°50'E., 405 m, 1 August 1972, 2 8 , 1 9 (AM P.19389) ; off Botany Bay, 34°00'S., 151°43'E. to 33°54'S., 151°47E., 420 m, 6 November 1972, 1 9 (AM P.19390) ; south of Port Hacking, 34°19'S., 151°24'E. to 34°13'S., 151°28'E., 360 m, prawn trawl, 28 June 1971, 1 4 (AM P.17951) ; north of Jervis Bay, 34°56'S., 151°10'E. to 35°01'S., 151°07'E., 558-522 m, trawled 7 July 1971, 2 8 , 1 9 ; (AM P.17946) ; south of Ulladulla, 35°31'S., 150°45'E. to 35037'5., 150°42'E., 423-405 m, prawn trawn, 8 July 1971, 2 9 (AM P.17953).




Body spindle shaped, ratio of length to width 2.4:1.


Head broadly oval, width about twice length, frontal margins ridged, medial anterior projection meeting frontal lamina. Eyes widely separated, situated laterally on antero-inferior surface of head and concealed in dorsal view, elongate triangular; base lateral, concave. Frontal lamina triangular. Clypeus anteriorly rounded, projecting anteriorly beyond frontal lamina, lateral margins with a "shoulder" anteriorly, posteriorly expanded laterally beyond saddle-shaped labrum.


Pereon just over half total length. Pereonites 1-5 of about equal length, pereonite 6 slightly shorter than others, pereonite 7 half length of pereonite 1. Pereonites 3-7 about equal width, about twice width of head, first two pereonites decreasing in width anteriorly to posterior margin of head. Coxal plates laterally ridged, last two with weak central ridge, first two quadrate, remainder produced posteriorly, last coxal plate reaching to midway along pleonite 2.


Pleon about one-fifth length, pleonites subequal in length, pleonite 1 extending laterally to half way along last coxal plate, pleonites 2-5 laterally produced, pleonites 2-4 curved posteriorly, pleonite 3 terminating just anterior to pleonites 4 and 5 which terminate at the same level posteriorly.


Telson barely exceeding pleon in length, roughly shield-shaped, sub-truncate posteriorly, dorsal surface with a weak longitudinal carina along midline, posterior margin with three acute teeth laterally (and sometimes a small fourth tooth) and a slightly broader and longer medial tooth, the tip of which is truncate or bifid ; intervals between teeth setose.


Antennula short, reaching to distal end of antennal peduncle; peduncle of three segments. Antenna long, extending to anterior margin of pereonite 2, peduncle of five segments, first two short; flagellum multi-segmented.


Inner endite of maxillula with four distal spines which are centrally plumose and apically naked. Outer endite of maxillula with eleven stout spines on medial margin, seven in a group distally and five in a line in proximal half.


Maxilliped endite with six coupling hooks on medial margin.


All other mouthparts generally similar to those of other species of genus.


Pereopod 1 with long basis almost equal to half total length, naked except for few setae distally; ischium expanded distally with few short spines mid-ventrally and around distal edge; merus dorsally produced and tipped by stout spines distally, ventrally bilobate with a few stout spines ; carpus with a few short spines ventrally ; propodus weakly com­pressed, ventrally carinate with a few short, stout spines ; dactyl with weak lateral ridge, terminating the claw.


Pereopods 2 and 3 similar to pereopod 1 except dorsal distal projection of merus longer, extending to midway along propodus.


Pereopods 4-7 similar to each other ; no segment with special projec­tions, ischium, merus and carpus similar in shape, slightly expanded distally ; basis about two-fifths total length of leg; stout setae around distal margins of ischum, merits, carpus and propodus, and in a transverse group midway along ventral surface of ischum, merus and carpus and in 2-4 groups along ventral surface of propodus.


Pleopods generally similar to those of other species of genus.


Uropod exopod of about equal width throughout its length, oblong; lateral and distal edges setose, short spines along lateral and distal edges ; posterolateral corner with a small tooth. Endopod larger than exopod, subtriangular; posterolateral corner acute but not produced, bearing a small tooth ; edges setose, short teeth along distal part of lateral edge and along distal edge.




The new species is similar to Bathynomus doderleini, B. affinis and B. decemspinosus in most features. The outer endite of the maxillula possesses 11 spines as is usual in the genus.


The principal differences concern the shape and ornamentation of the uropods ; there are also differences in the armature of the legs and of the telson. This species has a narrower body than B. affinis and is rather similar to B. doderleini in shape. The medial carina of the telson is lower than in most other Bathynomus species.


The number of teeth on the lateral edge of the exopod of the uropod ranges from 8 to 12 (thirteeen specimens with 9-10 teeth) and the number of teeth on the distal edge is generally 3 (seventeen specimens) but sometimes 2 (two specimens). The number of teeth on the lateral edge of the endopod of the uropod ranges from 3 to 6 and is most commonly 4 or 5 (fourteen specimens) ; there are 6-10 teeth on the distal edge but usually 8 or 9 (fourteen specimens).


On the posterior edge of the telson the medial tooth is truncate or bifid (notched) in all but one specimen. Nine specimens possess a small tooth lateral to the usual three on each side of the midline.


Pereopods 4-7 are slightly stouter than in B. doderleini and there are setae and spines around the distal edge of the carpus and propodus whereas in B. doderleini setae occur only on the ventral half of the distal edge of the carpus and are absent from the propodus.


The endopod of the uropod is not prominently produced at the postero­lateral corner as in B. decemspinosus and B. affinis and the exopod is about as wide distally as proximally, whereas in other species the exopod narrows noticeably towards the distal edge.


Finally, the copulatory organ (attached to the second pleopod) of the male slightly surpasses the distal edge of the endopod and is apically expanded. These are obvious differences from B. doderleini (see Milne Edwards and Bouvier, 1902) however, this structure has not been described for most species.


The new species is named after the N.S.W. State Fisheries Research Vessel Kapala in recognition of the assistance that this ship and its crew have given to recent scientific programmes on the deep water marine fauna off eastern Australia.”



(Griffin, 1975: 104-108)


Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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