Peraeospinosus exiliremis, Błażewicz-Paszkowycz, 2005

Błażewicz-Paszkowycz, Magdalena, 2005, Revision of the genus Peraeospinosus Sieg, 1986 (Crustacea: Peracarida: Tanaidacea), Journal of Natural History 39 (45), pp. 3847-3901 : 3884-3888

publication ID	https://doi.org/ 10.1080/00222930500450879
persistent identifier	https://treatment.plazi.org/id/03A787E0-FF83-FF94-FE50-FEAEFD484715
treatment provided by	Felipe
scientific name	Peraeospinosus exiliremis
status	sp. nov.

Treatment

Peraeospinosus exiliremis View in CoL n. sp.

( Figures 17 View Figure 17 , 18 View Figure 18 )

Material examined Holotype: non-ovigerous ♀ ( ZMH 40990), ANDEEP PS 61/114-4; 58 ° 24.969S,

25 ° 0.849W; 22 March 2002, multibox corer, depth 2293 m. Paratype: non-ovigerous ♀ dissected on the slides ( USNM 1082153 View Materials ), Eltanin 12, Sta. 991, 60 ° 579S, 56 ° 529W; Blake trawl, depth 3020 fathoms .

Diagnosis

Female without oostegites. Body about 8.5 times as long as wide. Carapace smooth, swollen, as long as wide, truncated anteriorly. Pereonite 1 subequal to carapace length (0.8), rostrum distinctive. Pereonites 1–5 trapezoidal, longer than wide. Pereonite 6 very short (2.5 times as wide as long). Pleon narrower than pereonites, pleon 0.7 times carapace length, twice as long as pereonite 6. Pleotelson rectangular. Antennule article 3 three times as long as article 2. Propodus of pereopod 2 length: width ratio about 4.5. Pereopods 4–6 merus and carpus with few strong and rarely distributed spines. One distal seta of pereopod 6 propodus longer than unguis, other two well-calcified. Pleopods with weakly developed setae (most are short and simple). Uropod exopod slightly longer than endopod.

Etymology

The name reflects the weakly developed pleopods that are used by tanaids for swimming or producing water current in tubes (Latin: exilis + remus 5meagre+oar).

Description

Female without oostegites, body length 6.8 mm ( Figure 17A View Figure 17 ).

Body. Body about 8.5 times as long as wide.

Cephalothorax. Carapace smooth, as long as wide, swollen posteriorly, truncated anteriorly.

Pereonites. Pereonite 1 trapezoidal, about as long as wide, pereonites 2–5 narrowed medially, little longer than wide. Pereonite 6 very short (2.5 times wider than long).

Pleon. Pleon narrower than pereon; twice as long as pereonite 6. All pleonites similar in size. Pleotelson rectangular.

Antennule ( Figure 17B View Figure 17 ). Article 1 a little longer than articles 2 and 3 combined, with three groups of simple and pinnate setae on outer margin; inner margin with row of four rod setae. Article 2 one-third length of article 3, with three rod setae distally. Article 3 with seven simple setae and one pinnate apical setae.

Antenna ( Figure 17C View Figure 17 ). Article 3 with minute seta. Article 4 almost twice as long as article 5, with three rod setae and three pinnate setae distally. Article 5 with one simple seta distally. Article 6 very short, with five terminal setae.

Mouthpart. Labrum not dissected. Mandible typical for genus; molar process ( Figure 17D View Figure 17 ) well-developed, with undulated margins with bunch of well-calcified setae at ‘‘lower’’ margin. Maxillule ( Figure 17E View Figure 17 ) with nine apical spiniform setae (two of them fused together); three of the setae swollen and well-calcified distally. Maxilla and labium lost during dissection.

Maxilliped ( Figure 17G View Figure 17 ). Typical for genus. Basis fused in heart-shaped plate with two pinnate setae; endite with two simple setae and two flat setae (tubercles) distally. Palp article 1 naked. Article 2 wedge-shaped, with two weakly serrated setae and one simple seta on inner margin and one minute seta on outer margin. Article 3 trapezoidal, inner margin with one simple, one serrated seta and two weakly serrated setae swollen distally. Article 4 slender, with one simple seta in outer margin and five sparsely serrated distal setae (one seta distally swollen).

Cheliped ( Figure 17F View Figure 17 ). Basis robust; merus wedge-shaped with long, well-calcified rod seta; carpus with row of five small rod setae dorsally and two well-calcified rod setae ventrally; propodus 1.3 times as long as carpus, with seta on inner side and short seta distally on dorsal margin; fixed finger (propodus projection) tipped with a strong spine, with two to three teeth, three rod setae dorsally, and two setae ventrally; one setae near insertion of dactylus; dactylus slightly curved, with two strong spiniform setae ventrally and one short rod seta proximally on dorsal margin.

Pereopod 1 ( Figure 18A View Figure 18 ). Basis with one pinnate seta in proximal part only and three short rod setae along article; ischium naked; merus subequal to carpus, with three short setae distally; carpus with five simple setae and one rod seta; merus and carpus combined longer than propodus; propodus with one simple and two rod setae distally, propodus length: width ratio 5.75; dactylus half as long as unguis.

Pereopod 2 ( Figure 18B View Figure 18 ). Basis little longer than rest of articles combined, naked; ischium naked; merus and carpus subequal, each with one robust spiniform seta and two setae distally; propodus a little shorter than merus and carpus combined, with minute spine ventrally and two rod setae dorsally; propodus length: width ratio is 4.5; dactylus tipped with slightly longer well-calcified unguis.

Pereopod 3 ( Figure 18C View Figure 18 ). Similar to pereopod 2 but carpus with two spiniform setae distally.

Pereopod 4 ( Figure 18D View Figure 18 ). Basis half as long as wide, with two pinnate setae distally; ischium with two setae; merus a little longer than carpus with two strong spiniform setae on ventral margin and sharp, well-calcified spines; carpus with two distal hooks and one seta dorsally; ventrally, large prickly tubercles surrounded by row of well-calcified and sparsely distributed strong spines; propodus with two spiniform setae ventrally and long distal seta; dactylus tipped with weakly bifurcated unguis; row of teeth on ventral margin of dactylus.

Pereopod 5 ( Figure 18E View Figure 18 ). Similar to pereopod 4; but basis with pinnate setae and one rod seta proximally.

Pereopod 6 ( Figure 18F View Figure 18 ). Similar to pereopod 5; basis with two pinnate setae; propodus tipped with terminal setae (two very short, coarsely serrated and one finely serrated, reaching over unguis).

Pleopods ( Figure 18G View Figure 18 ). All pleopods similar in structure; exopod with short and simple setae on distal part; endopod with five setae on lower margin two long, feather and three short, simple setae; one plumose seta on inner margin (length: width ratio of both exopod and endopod 3.0); no proximal setae on exopod or endopod.

Uropod ( Figure 18H View Figure 18 ). Both rami uni-articled, exopod a little longer than endopod; endopod with three pinnate setae at the middle, tipped with five simple terminal setae (two short); exopod with short simple seta on outer margin, tipped with one strong seta and one minute setae.

Distribution

Species known from Antarctic Peninsula and Weddell Sea ( Figure 25 View Figure 25 ).

Remarks

Peraeospinosus exiliremis can be distinguished from the other species of Peraeospinosus by the pleon, which is narrower than the pereon, the weakly developed pleopods, and the uropod exopod being slightly longer than the endopod.