Paramunida parvispina, Cabezas, 2010

Cabezas, P. E., 2010, Taxonomic revision of the genus Paramunida Baba, 1988 (Crustacea: Decapoda: Galatheidae): a morphological and molecular approach, Zootaxa 2712, pp. 1-60 : 34-36

Paramunida parvispina n. sp.

( Figs. 8, 14D)

Material examined. Holotype: Chesterfield Islands . EBISCO, Stn CP 2571, 20º26.15’S, 158º45.06’E, 14 October 2005, 298– 309 m: ov. F 7.0 mm (MNHN-Ga7488).

Paratypes: Chesterfield Islands . EBISCO, Stn CP 2571, 20º26.15’S, 158º45.06’E, 14 October 2005, 298– 309 m: 11 M 6.5–8.2 mm, 13 ov. F 7.0– 7.4 mm, 2 F 7.3–8.3 mm (MNHN-Ga7489) .

Etymology. From the Latin parvus, little, in reference to the small median gastric spine.

Description. Carapace: As long as broad. Spinules on gastric and hepatic regions usually not forming groups, lacking scaly striae and with few short uniramous setae. Epigastric region with 2 spines, each behind supraocular spine; without median row of spines behind rostral spine. Mesogastric region with small median spine. Cervical groove febbly discernible. Cardiac and anterior branchial regions slightly circumscribed. Cardiac region with a median row of 3 small spines, first thicker than others. Each branchial region with row of small spines near cardiac region. Frontal margin slightly concave. Lateral margins slightly convex, with some spines and setae on anterior half. Anterolateral spine well developed, reaching sinus between rostral and supraocular spines. Rostrum triangular, larger than supraocular spines, with thin dorsal longitudinal carina; margin between rostral and supraocular spines straight or slightly concave ( Figs. 8A, B).

Sternum: Thoracic sternite 4 with few arcuate striae; sternites 5–6 smooth or with 1 or 2 short striae on each lateral side, sternite 7 smooth ( Fig. 8C).

Abdomen: Abdominal somites 2–3 each with 4 small spines on anterior ridge, posterior ridge with 2 median spines. Abdominal somite 4 with 4 small spines on anterior ridge; posterior ridge with small but distinct small median spine ( Fig. 8A).

Eyes: Maximum corneal diameter more than one-third distance between bases of anterolateral spines.

Antennule: Segment 1 slightly exceeding corneae, with distomesial spine small and slightly shorter than distolateral; twice longer than wide and with fringe of long setae along lateral margin; lateral margin with distal slender portion about half as long as proximal inflated portion ( Fig. 8D).

Antenna: Anterior prolongation of segment 1 overreaching antennular segment 1 by one-fourth of its length. Segment 2 about twice length of segment 3 and twice longer than wide, ventral surface with few scales; distomesial spine mucronated ending in small distal point, reaching end of segment 3, nearly reaching midlength of anterior prolongation of segment 1,, distolateral spine not reaching end of segment 3; third segment 1.5 times longer than wide and unarmed ( Fig. 8D).

Maxilliped 3: Ischium about twice length of merus measured along dorsal margin, distoventrally bearing one spine; merus with well developed median spine on flexor margin; extensor margin unarmed ( Fig. 8E).

Pereopod 1: Long and slender, squamate, 6.2–6.6 times carapace length; carpus 0.8–1.1 times palm length, and 10–11.6 times longer than height; palm 1.4–1.5 times fingers length. Base of carpus without bundle of setae ( Fig. 8F).

Pereopods 2–4: Long and slender, with scales on lateral sides of meri and carpi and few scales on propodi; scales with short setae. P2 3.7–4.1 times carapace length, merus 1.7–1.8 times longer than carapace, 13–17

times as long as high, 3.5–4.0 times as long as carpus and 1.5–1.8 times as long as propodus; propodus 11–15 times as long as high, and 1.6–2.1 times dactylus length. Merus with well developed spines on dorsal border, increasing in size distally, ventral margin with few spines and one well-developed distal spine; row of small spines along ventrolateral margins. Carpus with some small dorsal spines, distal spine on dorsal and ventral margin. Propodus with small movable ventral spines. Dactylus compressed, slightly curved, with longitudinal carinae along mesial and lateral sides, ventral border unarmed. End of P2 carpus reaching end of P1 merus. P3 with similar spination and segment proportions as P2; merus as long as P2 merus; propodus and dactylus as long or slightly longer than those of P2. P4 slightly shorter than P2; merus 1.4–1.5 times carapace length; propodus and dactylus similar in length to those of P3; merocarpal articulation clearly exceeding end of anterior prolongation of first segment of antennal peduncle ( Figs. 8G–I).

lateral view. Scales: A–C = 1 mm; D–E = 0.5 mm; F–I = 2 mm.

Remarks. The species resembles P. antipodes from eastern Australia but both can be differentiated by the following characters:

— P. antipodes has one well-developed mesogastric spine (rarely two), whereas this spine is very small in P. parvispina .

— The distomesial spine of the antennal segment 2 clearly overreaches the end of the antennal segment 3 in P. antipodes , whereas this spine only reaches the end of the segment 3 in P. parvispina .

Distribution. Chesterfield Islands, between 298 and 309 m.