Peraeospinosus peculiaroides, 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 : 3888-3890

Peraeospinosus peculiaroides sp. nov.

( Figure 19 )

Material examined

One ♀, ZMUC CRU-3885 , R / V Galathea Sta. 280, Seychelles-Ceylon [5 Sri Lanka], 1 ° 569N, 77 ° 059E, depth 4350 m, 9 April 1951 .

Diagnosis

Female. Pereonites 2–5 longer than wide; pereon almost half carapace length. Pleotelson rectangular posteriorly. Antennule article 3 four times as long as article 2. Propodus of pereopod 2 length: width ratio about 4. One of three distal setae on propodus of pereopod 6 reaching over dactylus, two others as long as dactylus. Pereopods 4–6 unguis without teeth below bifurcated tip. Pereopods 4–6 merus and carpus with small and numerous spines ventrally. Pleopod endopod with one dorsal seta; no clear gap between proximal seta and the remaining ones. Uropod exopod slightly shorter than endopod.

Etymology

The name reflects former classification to the Peraeospinosus peculiaris .

Description

Female without oostegites ( Figure 19 ).

Cephalothorax. Missing.

Pereonites. Pereonites 1–4 subequal, longer than wide, pereonite 5 as long as wide; pereonite 6 the shortest, half length of pereonite 5.

Pleon. Pleon and pleotelson combined as long as pereonite 1; all pleonites similar in size; pleotelson rectangular.

Appendages. For description and figures of appendages see Lang (1968, p 161–166). Distribution

Species known only from the type locality: Seychelles-Ceylon [5 Sri Lanka], 1 ° 569N, 77 ° 059E, depth 4350 m ( Lang, 1968) ( Figure 25 ) .

Remarks

The description and figures by Lang (1968, p 162, 164–165, Figures 99–101) are carefully and completely prepared. Some missing details of mandible molar and pereopods 5 and 6 are given in Figure 19 .

The type specimen of Peraeospinosus peculiaroides is missing the carapace, nevertheless the characters displayed by rest of the body and the dissected appendages distinguish it clearly from P. peculiaris s. str. Pereonite 1 of P. peculiaroides is almost subequal to pereonite 2 and pereonite 6 is half the length of pereonite 5, while in P. peculiaris pereonite 1 is clearly shorter than pereonite 2 and pereonite 6 is two-thirds the length of pereonite 5. The cheliped carpus of P. peculiaris is stout (1.6 times as long as wide) and armed with seven rod setae on the dorsal edge; in P. peculiaroides ( Lang 1968, p 164) it is about twice as long as wide and armed with 16 rod setae dorsally. Bases of all pereopods in P. peculiaris have more (about six) rod setae and the merus and carpus of pereopods 4–6 are delicately setose (poorly calcified) on the ventral side. On the contrary, P. peculiaroides has fewer setae on the bases of the pereopods (not more than four) and the merus and carpus of pereopods 4–6 are armed ventrally with strong spines. Propodus of pereopod 6 has one long and two short setae distally in both species, but the two short setae are as long as the dactylus in P. peculiaroides and only half as long as the dactylus in P. peculiaris . The gap between the most proximal and the other setae is clear in both pleopod rami in P. peculiaris , while it is not obvious on the exopod and is absent on the endopod in P. peculiaroides . Other differences can be observed in the mouthparts of both species; the setae on the molar process of the mandible are long and relatively thin in P. peculiaris , while they are short but more calcified in P. peculiaroides .

Figures

Figure 19. Peraeospinosus peculiaroides n. sp., holotype female (ZMUC CRU-3885). (A) Female dorsal view; (B) left mandible; (C, D) pereopod 5 and 6, respectively. Scale bars: 1.0 mm (A); 0.1 mm (B–D).

Figure 25. Distribution of genus Peraeospinosus based on Beddard (1886a, 1886b), Kudinova-Pasternak (1966, 1969, 1990), Lang (1968), and Shiino (1978).