Catenarius magdae, Bamber, Roger N. & Marshall, David J., 2015

Bamber, Roger N. & Marshall, David J., 2015, Tanaidaceans from Brunei, V. The Leptocheliidae (Crustacea: Peracarida: Tanaidacea), with four new species, Zootaxa 3948 (3), pp. 342-360 : 352-355

Catenarius magdae sp. nov.

Figs 6–7

Material: Holotype. Female with oostegites, ( NHMUK 2015. 2885), Station S5, 04°42′26.5"N 114°26′02"E, 11.5 m depth, sand. March, 2009.

Paratypes. One ♀ with empty brood pouch, (dissected on microslide, NHMUK 2015. 2886), sample BU3; one pre-adult ♂ (damaged), ( NHMUK 2015. 2887), sample B12; both Station B, 04°51′06"N 114°35′26"E, 20 m depth, sand.March, 2009.

Description of female. Body ( Fig. 6 A) slender, holotype 1.6 mm long, seven times as long as wide. Cephalothorax subrectangular, 1.3 times as long as wide, longer than pereonites 1 and 2 together, with slight rostrum and single mid-lateral setae; eyelobes rounded, eyes present and black. Pereonites with single anterolateral setae (pereonite 1), or naked (pereonites 2 to 6); pereonite 1 one-third as long as cephalothorax and twice as wide as long; pereonites 2 and 3 equal in length, 1.5 times as long as pereonite 1 and about 1.5 times as long as wide; pereonites 4 to 6 subequal in length, about as long as wide, and about twice as long as pereonite 1. Pleon 1.5 times as long as pereonite 6; each pleonite about 5.5 times as wide as long, with paired (pleonites 1 to 4) or single (pleonite 5) mid-lateral setae. Pleotelson semicircular, as long as last two pleonites together, twice as wide as long, with one lateral, one laterodistal and one distal setae on each side.

Antennule ( Fig. 6 B) of three peduncular articles, flagellum of two segments. Proximal peduncular article three times as long as wide, as long remainder of antennule, with proximal and mid-length paired penicillate setae on outer margin, and outer distal simple seta; second article 1.5 times as long as wide, one-third as long as first article, with two inner-distal penicillate setae and one outer simple distal seta shorter than article; third article 1.4 times as long as second, naked. First flagellar segment one-third as long as distal peduncular article, distally with three simple setae and one aesthetasc; second flagellar segment minute, with four simple distal setae.

Antenna ( Fig. 6 C) proximal article compact, naked; second article 1.6 times as long as wide, distally with ventral and dorsal setae; third article shorter than second, with dorsodistal spine; fourth article longest, five times as long as wide and twice as long as third, with four distal simple setae; fifth article three-quarters as long as fourth, with two distal setae; flagellum minute, with four distal setae.

Labrum ( Fig. 6 D) hood-shaped, distally setose. Left mandible ( Fig. 6 E) with three rounded distal crenulations on narrow lacinia mobilis, slight crenulations on pars incisiva, pars molaris blunt with distal rugosity; right mandible ( Fig. 6 F) similar but without lacinia mobilis, pars incisiva distally bifid and with five fine marginal crenulations. Labium ( Fig. 6 G) wide, bilobed, distally finely setose. Maxillule ( Fig. 6 H) endite with ten distal spines and sparse marginal setae, palp with two subequal distal setae. Maxilliped ( Fig. 6 I) palp first article naked, second article with three inner setae, two distal setae and one outer seta; third article with three longer and four shorter inner marginal setae; fourth article with three inner to distal simple setae and one mesial and one outer subdistal setae; basis with three distal setae; endites ( Fig. 6 J) distally with outer simple seta, two pointed spines and one rounded inner blunt tubercle. Epignath not recovered.

Cheliped ( Fig. 7 A) comparatively slender, with rounded basis 2.4 times as long as wide, naked; merus triangular with two unequal ventral setae; carpus 2.5 times as long as wide, with three ventral setae and five dorsal marginal setae; propodus 1.6 times as long as wide, with inner distal “comb” not evident, single outer seta at base of dactylus; fixed finger with two ventral setae and three setae adjacent to slightly crenulate cutting edge; dactylus with inner proximal seta and one seta on cutting edge.

Pereopod 1 ( Fig. 7 B) longer than other pereopods, coxa with seta; basis sinuous, four times as long as wide, with single dorsoproximal simple seta; ischium compact with one ventral seta; merus one-third as long as basis, with single ventrodistal seta; carpus 1.3 times as long as merus, with five distal setae; propodus 1.9 times as long as carpus, with three setae on subdistal dorsal mound and one subdistal ventral seta; dactylus slender and bearing proximal seta, extending into shorter slender unguis 0.7 times as long as dactylus, the two together 1.3 times as long as propodus. Pereopod 2 ( Fig. 7 C) more compact than pereopod 1; basis 3.6 times as long as wide, naked; ischium with one ventral seta; merus 0.3 times as long as basis, with ventrodistal spine; carpus 1.5 times as long as merus, with single dorsodistal seta; propodus 1.2 times as long as carpus, with one dorsodistal seta; dactylus and short unguis together half as long as propodus. Pereopod 3 similar to pereopod 2.

Pereopod 4 ( Fig. 7 D) basis stout, 2.7 times as long as wide, naked; ischium with two ventrodistal setae; merus short, 0.2 times as long as basis, with paired ventrodistal spines; carpus 2.2 times as long as merus, with outer, ventral and inner distal spines and fine dorsodistal seta; propodus 1.3 times as long as carpus, with two ventrodistal spines and two dorsodistal setae shorter than dactylus; dactylus and unguis not fused, together 0.8 times as long as propodus. Pereopod 5 as pereopod 4. Pereopod 6 ( Fig. 7 E) similar to pereopod 4, but propodus with additional three finely-denticulate distal setae.

Pleopods ( Fig. 7 F) all alike, all setae plumose; basis naked, endopod with one inner seta and twenty outer setae; exopod with nineteen outer and one proximal setae.

Uropod ( Fig. 7 G) biramous, basis naked; exopod of two segments, as long as proximal endopod segment, setose as figured; endopod of six segments, distal segments slender.

Pre-adult male: Generally as female, cheliped as that of female. Antennule ( Fig. 7 H) in intermoult, showing multisegmented flagellum internally. Pleon missing from specimen.

Etymology. Named after the tanaidacean researcher Magda Błażewicz-Paszkowycz, in gratitude for extensive and enjoyable collaboration on tanaidaceans and prawns.

Remarks. Catenarius magdae sp. nov. has the antennal, maxilliped endite and uropod morphology entirely consistent with the type of the genus, C. daviei . Re-examination of the generotype has confirmed that the second article of the antennal peduncle bears distal flexible setae rather than slender spines, as originally interpreted by Bamber (2008).

Catenarius magdae is distinct from C. daviei in its more elongate cephalothorax (just longer than wide in C. daviei ), its more elongate third antennular peduncle article (shorter than the second article in C. daviei ), more slender antennal articles, subtle differences in the pereopod setation (notably the distal carpal setation of pereopod 1), and in having six (rather than five) segments in the adult uropod endopod.

Catenarius magdae was taken sparsely in clean sands at 11 to 20 m depth.

Figures

FIGURE 6. Catenarius magdae sp. nov., A, holotype female, dorsal; B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible, distal; G, labium; H, maxillule; I, maxilliped; J, maxilliped endite. Scale line = 0.5 mm for A, 0.1 mm for B to J.

FIGURE 7. Catenarius magdae sp. nov., A, right cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 4 with detail of carpal spine; E, pereopod 6 with detail of propodal spine; F, pleopod; G, right uropod; H, antennule of pre-adult male (from in situ). Scale line = 0.2 mm.