Carpoapseudes spinigena, Bamber, 2007

Bamber, Roger N., 2007, Suborders Apseudomorpha Sieg, 1980 and Neotanaidomorpha Sieg, 1980 *, Zootaxa 1599, pp. 13-40 : 19-25

Carpoapseudes spinigena n.sp.

Figures 4–6

Material examined. Holotype, female (KMNH IvR 500.153), station XR-2(1), 42º27.52’– 42º26.85’N 144º15.47’– 144º12.98’E, 974–965 metres, 3 m ORE beam trawl, 15 September 2001. Paratypes: 1 brooding female, 2 females with oostegites, 7 females without oostegites, 6 males (KMNH IvR 500.154), 1 female with oostegites (dissected, KMNH IvR 500.155), same locality .

Diagnosis. Typical Carpoapseudes but with lateral spiniform apophyses at anterior margin of branchial chambers. Cephalothorax with conspicuous pointed rostrum with “shoulders” at its base, as long as ocular spiniform apophyses; pleotelson less than half length of whole pleon, 6.2 times as long as wide. No proximal auricular expansion on the propodus of the male cheliped.

Etymology. From the Latin, meaning “spine-cheek” (noun in apposition), owing to this species having lateral spiniform apophyses on the anterior margin of the branchial chamber.

Description of female

Body ( Fig. 4A). Dorsoventrally flattened, elongate, holotype 9.8 mm long (tip of rostrum to posterior of pleotelson), 6 times as long as wide, narrower posteriorly.

Cephalothorax. Sub-triangular, as long as wide, anterior margin with conspicuous pointed rostrum with “shoulders” at base. Eyes absent; eyelobes modified to prominent spine-like apophyses directed antero-laterally; lateral spiniform apophyses at anterior margin of branchial chambers.

Pereonites. Pereonites 1 and 2 subequal, about one-third as long as cephalothorax, lateral margins uniformly convex. Pereonites 3, 4 and 5 subequal (4 longest), 1.5 times as long as pereonite 1, with anterolateral spine-like apophyses and expanded postero-laterally at attachment of coxae. Pereonite 6 shortest, 0.8 times as long as pereonite 1, trapezium-shaped, without lateral apophyses (all pereonites respectively 2.8, 2.4, 1.3, 1.0, 1.1 and 2.1 times as wide as long). Ventral hyposphenia present on pereonites 2, 3 and 5.

Pleon twice as long as pereonite 4, of five free subequal pleonites bearing pleopods. Pleonites dorsally convex, more than twice as wide as long, laterally expanded by spiniform apophyses.

Pleotelson ( Fig. 4B) long and slender, 0.4 times as long as whole pleon, 6.2 times as long as wide, with sparse lateral setae.

Antennule ( Fig. 4C). Peduncle 4-articled. Proximal article elongate, 4.7 times as long as wide, setose as figured. Second article 0.3 times as long as article 1, with distal crown of longer and shorter setae. Third article two-thirds length of second, fourth article one-third as long as third, naked. Main flagellum of 12 segments, articles 7, 10 and 12 bearing two, one and one aesthetascs respectively. Accessory flagellum of five segments.

Antenna ( Fig. 4D). Proximal peduncle article with outer spiniform apophysis. Article 2 bearing elongate squama with six simple marginal setae. Peduncle article 3 as long as wide, with one seta. Articles 4 slightly longer than article 5 and three times as long as article 3. Flagellum of eight segments.

Mouthparts. Labrum ( Fig. 5A) rounded simple, distally naked; stout, sharp epistome present. Right mandible ( Fig. 5B) with outer margin finely setose, bearing strong, crenulated pars incisive, setiferous lobe with six mainly bifurcate setae, pars molaris robust, blunt; mandibular palp of three articles, proximal article just longer than wide with two small medial setae, article 2 3.4 times as long as article 1 with two parallel rows of six longer and ten shorter simple setae in distal third; article 3 half length of article 2 with nine inner simple setae, two ventral subdistal simple setae, and three longer distal setae, inner two of which are finely denticulate. Left mandible ( Fig. 5C) as right but with crenulate lacinia mobilis. Maxillule ( Fig. 5E) inner endite with finely setose outer margin and five finely setulate distal setae; outer endite with ten distal spines and two subdistal setae, outer margin finely setose; palp of two stout articles, distally with eight setae. Maxilla ( Fig. 5F) with serrations on outer margin; outer lobe of moveable endite with two simple setae on outer margin; inner lobe of movable endite with simple setae; outer lobe of fixed endite with two simple, two bifurcate, and five trifurcate spiniform setae and three inner subdistal spines; inner lobe of fixed endite with rostral row of 24 setae guarding six longer setae. Labium ( Fig. 5D) with distally-serrated outer margin and setulose distal margin, palp with fine lateral setules and two simple distal setae. Maxilliped ( Fig. 5G). Basis naked; palp article 1 with single seta on outer margin; palp article 2 longer than wide, with rows of numerous short setae on inner margin, outer margin with two simple setae sub-distally; palp article 3 as long as wide, with three shorter and six longer simple setae along expanded inner margin; palp article 4 with seven distal setae. Endite ( Fig. 5H) with compound (“leaf-like”) inner caudo-distal seta and stout, spatulate, distal spines. Epignath large, cupshaped, with inner lobe and distal seta.

Cheliped ( Fig. 6A). Not slender. Basis twice as long as wide, dorsally naked, ventrally with tiny proximal seta, mid-ventral seta and tuft of six distal setae. Exopodite present, 3-articled, second article naked, attenuate, distal article with four plumose setae. Merus elongate, narrowing proximally, with single dorsodistal seta and ventral row of setae, often paired. Carpus twice as long as wide, with four simple setae along ventral margin, proximal and distal simple setae just below dorsal margin, and subdistal dorsal apophysis with paired adjacent setae. Chela fingers longer than palm, ventral margin with seven setae; two setae near articulation of fixed finger; cutting edge of fixed finger with row of fine setules interspersing squared “teeth”, but no apophyses, distal claw rounded. Dactylus with fine setae but no apophyses on cutting edge, distal claw pointed.

Pereopod 1 ( Fig. 6B). With pronounced spine-like apophysis on coxa. Basis stout, 3.5 times as long as wide, naked. Exopodite present, 3-articled, article 2 naked, article 3 with five distal plumose setae. Ischium with three simple ventrodistal setae. Merus half as long as basis, with rows of ten ventral setae and five fine outer mesial setae, and three dorsodistal simple setae. Carpus slightly longer than merus, three times as long as wide, with dense rows of dorsal and ventral marginal setae, ventrally with three finely pectinate spines in distal half, and four mesial setae. Propodus shorter than merus, with dense row of dorsal marginal setae, ventral marginal setae interspersed with four finely pectinate spines in distal half, distally with short, bilaterallydenticulate compound spine. Dactylus stout, with three mid-dorsal fine setae and three ventral denticulations; unguis short.

Pereopod 2 ( Fig. 6C). More slender than pereopod 1. Coxa with small spiniform apophysis. Basis 4.5 times as long as wide with tuft of ventrodistal setae. Merus 0.6 times as long as carpus, with elongate ventral setae in distal half. Carpus elongate, with rows of ventral and mesial setae, longer paired dorsodistal setae and ventrodistal pectinate spine. Propodus two-thirds as long as carpus, similarly setose but with ventrodistal pectinate spine. Dactylus slender with fine distal seta, unguis slender, as long as dactylus, the two together longer than propodus.

Pereopod 3 ( Fig. 6D) similar to pereopod 2, but propodus with ventrodistal bilaterally-denticulate compound spine. Unguis shorter than dactylus.

Pereopod 4 ( Fig. 6E). Similar to pereopod 2 but basis with plumose sensory setae. Merus proximally naked. Carpus with ventrodistal to distal crown of about 16 setae more than half as long as propodus. Propodus with mid-dorsal plumose sensory seta, dorsodistal tuft of five short and four long finely denticulate setae. Dactylus plus claw shorter than propodus and shorter than longest dorsodistal propodal setae.

Pereopod 5 ( Fig. 6F). Coxa without apophyses. Merus more than half length of carpus. Propodus just shorter than carpus, with ventral row of 16 short leaf-like, bilaterally-setulose spines. Dactylus and unguis slender, together as long as propodus.

Pereopod 6 ( Fig. 6G) similar to pereopod 5, but 14 ventral leaf-like propodal spines extending to a further 13 around distal margin of article.

Pleopods ( Fig. 4E). All alike. Basis elongate, with four dorsal and three ventral plumose setae. Endopod shorter than exopod without proximal articulation; both rami slender, with 21 plumose setae. Outer proximal seta on exopod sub-distally with robust setules, distally naked.

Uropod ( Fig. 4B). Biramous, both rami filiform, multi-segmented. Basis with two setae distally. Exopod less than half as long as endopod, with eight segments. Endopod elongate, three times as long as pleotelson, with 21 segments.

Distinctions of male. Generally as female.

Pereonites with sharply pointed hyposphenia, blunt penial tubercle on pereonite 6.

Antennule main flagellum of 17 segments, with no aesthetascs on segments 1, 2, 16 and 17, two on segments 5 and 6, and with single aesthetascs on remaining segments.

Cheliped ( Fig. 6I) proportionately larger, without lateral carpal setae, with rounded proximal apophysis on fixed finger.

Pereopods. Coxae of pereopods 5 and 6 each with small, spiniform apophysis ( Fig. 6H).

Remarks. The only other species of Carpoapseudes which have lateral spiniform apophyses on the anterior margin of the branchial chamber are C. auritocheles Kudinova-Pasternak, 1975 , and C. caraspinosus Dojiri & Sieg, 1997 . However, the apophyses in C. auritocheles are behind the midline of the cephalon, and this species also has a slender rostrum longer than the ocular apophyses, a pleotelson longer than four pleonites together, a more slender pereopod 1 dactylus, a proximal auricular expansion on the propodus of the male cheliped, and a number of differences in the mouthpart morphology ( Kudinova-Pasternak 1975). Although poorly described and figured, it is apparent that C. caraspinosus shows a number of similarities to C. spinigena n.sp., including the coxal spiniform apophysis on pereopod 2, and the subdistal dorsal apophysis on the cheliped carpus; however, it has anterior spiniform apophyses on pereonite 6, unlike the present species, as well as more numerous segments in the flagella of the antennule, a more slender cheliped and pereopod 1, the latter having the merus as long as or slightly longer than the carpus (shorter in C. spinigena ).

Although Guṭu (1996) includes a lack of lateral spiniform apophyses on the cephalon in his generic diagnosis for Carpoapseudes , the trapezoid sixth pereonite and the pereopod carpus being longer than the merus are characteristic of this genus and not of Leviapseudes , the only other genus in this subfamily.