Brodskius abyssalis, Markhaseva & Schulz, 2007

Markhaseva, Elena L. & Schulz, Knud, 2007, New species of Brodskius, Rythabis, and Omorius (Crustacea: Calanoida) from deep Antarctic waters, Journal of Natural History 41 (13 - 16), pp. 731-750 : 732-737

publication ID	https://doi.org/ 10.1080/00222930701297772
persistent identifier	https://treatment.plazi.org/id/444A8794-7B66-FFAC-FEC9-FB9EFDA5FBA4
treatment provided by	Felipe
scientific name	Brodskius abyssalis
status

Treatment

Genus Brodskius Markhaseva and Ferrari, 2005

Brodskius abyssalis sp. nov.

( Figures 1–3 View Figure 1 View Figure 2 View Figure 3 )

Material examined

Holotype: adult female, dissected, body length 1.28 mm ( ZMH K-41170). Weddell Sea, 67 ° 31 9 S, 00 ° 01 9 E, station 59-5, epinet, 14 February 2005, above the sea bed at depths of 4651–4655 m. GoogleMaps

Description

Adult female. Total length 1.28 mm; prosome 4.1 times longer than urosome. Rostrum without filaments ( Figure 1C, D View Figure 1 ). Cephalosome and pediger 1 incompletely separate, pedigers 4 and 5 separate ( Figure 1A, B View Figure 1 ); posterior corners significantly indented in lateral view ( Figure 1B, E, G View Figure 1 ). Spermathecae oblong-round ( Figure 1E, G, H View Figure 1 ). Caudal rami with four terminal, one small dorsal and a small ventral setae ( Figure 1E, F, J View Figure 1 ).

Antennule slightly longer than prosome. Antennule ( Figure 1K View Figure 1 ) of 24 free segments, armature as follows: I—3s, II–IV—6s+1ae, V—2s+1 ae, VI—2s, VII—2s+1 ae, VIII—2s, IX—2s+1ae; X–XI—4s+1ae, XII to XIII—1s each; XIV—2s+1ae, XV—1s, XVI—2s+1ae, XVII—1s, XVIII—2s, XIX—1s, XX—2s, XXI—1s+1ae, XXII to XXIII—1s each, XXIV to XXVI—2s each, XXVII–XXVIII—4s+1 ae.

Antenna ( Figure 2A View Figure 2 ): coxa and basis without setae; endopodal segment 1 with one seta, endopodal segment 2 with 12 setae; exopod seven-segmented with 0, 2, 1, 1, 1, 1, and 3 setae.

Mandible ( Figure 3A, B View Figure 3 ): gnathobase elongate, narrow; cutting edge narrow with deep incision; exopod of five segments with 1, 1, 1, 1, and 1 seta; endopod segment 1 with one seta, endopod segment 2 with nine setae; basis with one seta.

Maxillule ( Figure 3C View Figure 3 ): praecoxal endite with nine terminal and two posterior setae; coxal endite with two setae, coxal epipodite with six setae; proximal basal endite with four setae, one of them longer and thicker than others and heavily setulated; distal basal endite fused to endopod with 10 setae in total, two of them longer and thicker than others and heavily setulated; exopod with six setae.

Maxilla ( Figure 3D, E View Figure 3 ): proximal praecoxal endite with four setae, distal with three setae; proximal and distal coxal endites with three setae each; proximal basal endite with four setae, one of them thicker than others, one poorly sclerotized; distal basal endite plus endopod with eight sensory setae: five worm-like and three brush-like. Tips of worm-like sensory setae thread-like, one of brush-like setae thicker than others ( Figure 3E View Figure 3 ).

Maxilliped ( Figure 2B View Figure 2 ): syncoxa without seta on proximal praecoxal endite, two setae on middle endite, and three setae on distal praecoxal endite; coxal endite with three setae. Basis with three medial, two distal setae and row of denticles proximally. Endopod of five segments with 4, 3, 2, 2+1 and 4 setae.

P1 ( Figure 3F View Figure 3 ): basis with tiny distolateral seta and medial distal seta moderately curved; endopod one-segmented with three medial and two terminal setae and small denticles along lateral edge distally; lateral lobe poorly developed, triangular. Exopod threesegmented, segment 1 with lateral spine, segment 2 with lateral spine and medial seta, segment 3 with lateral spine, terminal spine and three medial setae. All lateral spines of comparatively great lengths, distal one slightly shorter.

P2 ( Figure 2C View Figure 2 ): coxa with medial seta; endopod two-segmented, segment 1 with one medial seta, segment 2 with two medial, two terminal and one lateral setae and spinules on posterior surface. Exopod three-segmented, segments 1 and 2 with lateral spine and medial seta each, segment 3 with three lateral spines, terminal spine and four medial setae.

P3 ( Figure 2D View Figure 2 ): coxa with medial seta; endopod three-segmented, segments 1 and 2 with one medial seta each, segment 3 with two medial, two terminal and one lateral setae; segments 2 and 3 with scattered spinules on posterior surface. Exopod three-segmented, segments 1 and 2 with lateral spine and medial seta each, segment 3 with three lateral spines, terminal spine as long as combined lengths of segments 2 and 3 and very finely serrate.

P4 ( Figure 2E View Figure 2 ): coxa with medial seta, basis without seta; only proximal exo- and endopod segments intact: endopod segment 1 with one medial seta; exopod segment 1 with one lateral and one medial seta. Posterior surface of coxa, basis, and endopod segment 1 with spinules.

P5 ( Figure 1L View Figure 1 ): uniramous, three-segmented; coxae naked and fused by intercoxal sclerite; basis with small patch of denticles distolaterally; exopod with denticles on posterior surface, one short lateral, a moderately long subterminal spine, a long terminal unarticulated extension, and one long medial spine, all toothed; short lateral spine hardly reaching base of subterminal spine; subterminal spine exceeding mid-length of terminal unarticulated extension; medial spine extending nearly to tip of terminal extension.

Male. Unknown.

Etymology

The specific name is derived from the Greek abyssos meaning bottomless, abyss, and refers to the type locality of the species.

Remarks

Markhaseva and Ferrari (2005) attributed four species to the genus Brodskius : B. benthopelagicus Markhaseva and Ferrari, 2005 , B. confusus Markhaseva and Ferrari, 2005 , B. paululus ( Park, 1970) , and B. robustipes ( Grice and Hulsemann, 1965) . The new species fits well the generic definition, but is distinguished from the above species by: (1) the lack of rostral filaments (present in other species); (2) presence of two setae on the second exopodal segment of the antenna (one seta in other species); (3) thread-like tips of maxillary worm-like sensory setae (not thread-like); and (4) the subterminal spine of P5 having moderate length surpassing mid-length of terminal unarticulated extension. The new species shares a long subterminal spine of P5 with B. confusus , however, it differs by a shorter lateral spine not reaching the base of the subterminal spine (exceeding the base in B. confusus ); in other congeners the subterminal spine not reaching or hardly reaching midlength of terminal extension.

An additional single female of an undescribed species of Brodskius was found in sample 042-2 at depths of 3680–3683 m (59 ° 40 9 S, 57 ° 35 9 W), collected on 27 January 2002, which could not be described due to poor condition. This specimen differs from congeners particularly by larger size (1.48 mm) and the presence of a well-developed rostrum furnished with two thick filaments.