Paramunida aspera, Cabezas & Chan, 2014

Cabezas, Patricia & Chan, Tin-Yam, 2014, Deep-sea squat lobsters of the genus Paramunida Baba, 1988 (Crustacea: Decapoda: Munididae) from the Philippines Panglao 2004, Panglao 2005 and Aurora 2007 expeditions, with the description of three new species, Raffles Bulletin of Zoology 62, pp. 302-316 : 306-308

Paramunida aspera , new species

( Figs. 2 , 4A )

Material examined. Holotype: AURORA 2007, Philippines, ovigerous female (CL 7.9 mm) (NMCR), station CP2695, 14°46'N, 123°39'E, 357–367 m, 26 May 2007 . — Paratypes: AURORA 2007, Philippines, 55 males (CL 5.0– 11.1 mm) , 50 females (CL 5.0–9.0 mm) ( NTOU A01409), station CP2695, 14°46'N, 123°39'E, 357–367 m, 26 May 2007 . — 2 females (CL 8.4–9.9 mm), 2 ovigerous females (CL 8.4–10.8 mm) ( NTOU A01410), station CP2696, 14°47'N, 123°42'E, 367–380 m, 26 May 2007 .

Description. Carapace: As long as broad. Dorsal surface covered with numerous granules and spinules; with few short simple setae. Epigastric region with two spines, each behind supraocular spine; without median row of spinules behind rostral spine. Mesogastric region with median row of three spines, first thicker than others. Anterior branch of cervical groove with short setae. Cervical groove distinct. Cardiac and anterior branchial regions slightly circumscribed. Cardiac region with a median row of three well-developed spines, first thicker than others. Each branchial region with row of spines near cardiac region. Frontal margin slightly concave. Lateral margins convex, with some spines and iridescent setae on anterior half. Anterolateral spine well developed, exceeding sinus between rostral and supraocular spines. Rostral spine spiniform, with thin dorsal longitudinal carina; supraocular spines well developed, shorter and slender than rostral spine; margin between rostral and supraocular spines slightly concave ( Fig. 2A, B ).

Sternum: Thoracic sternite 4 with numerous arcuate striae; sternites 5–7 with only few striae on each lateral side ( Fig. 2C ).

Abdomen: Abdominal somites 2–3 each with four welldeveloped spines on anterior ridge, posterior ridge with two median spines. Abdominal somite 4 with four spines on anterior ridge; posterior ridge with distinct single median spine. Ridges with numerous spinules and a few small spines ( Fig. 2A ).

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

Antennule: Article 1 exceeding corneae, with distomesial spine small and slightly shorter than distolateral; about twice longer than wide and with fringe of long setae along lateral margin; lateral margin with straight (distal) portion clearly shorter than convex (proximal) portion ( Fig. 2D ).

Antenna: Anterior prolongation of article 1 clearly overreaching antennular peduncle by about one-third of its length. Article 2 about 2.5 times length of article 3 and twice longer than wide, ventral surface with scales; distomesial spine spiniform, slightly exceeding antennal peduncle and without tuff of setae, reaching mid-length of anterior prolongation of article 1, and far from distal end of antennular article 1, distolateral spine nearly reaching end of article 3; article 3 as long as wide and unarmed ( Fig. 2D ).

Maxilliped 3: Ischium about 1.7 times length of merus measured along extensor margin, flexor margin bearing long distal spine; merus with well-developed median spine on flexor margin; extensor margin unarmed ( Fig. 2E ).

Pereopod 1: Long and slender, squamate, between 3.8–4.0 times carapace length; carpus about 1.1–1.2 palm length, and 5.3–5.5 times longer than height; palm about as long as fingers length. Base of carpus without bundle of setae ( Fig. 2F ).

Pereopods 2–4: Long and slender, with numerous scales on lateral sides of meri, carpi and propodi; scales with short setae. P2 2.6–2.9 times carapace length, merus 1.1–1.2 times longer than carapace, about 14 times as long as height, 4.1 times as long as carpus and 1.6–1.7 times as long as propodus; propodus about 11–13 times as long as height, and 1.2 times dactylus length. Merus with well-developed spines on extensor border, increasing in size distally, flexor margin with few spines and one well-developed distal spine; bearing row of small spines along flexolateral margin. Carpus with some small extensor spines, small distal spine on extensor and flexor margins. Propodus with small movable flexor spines. Dactylus compressed, slightly curved, with longitudinal carinae along mesial and lateral sides, flexor border unarmed. End of P2 carpus reaching end of P1 merus. P3 with similar spination and article proportions as P2; merus slightly shorter than P2 merus; propodus and dactylus about 1.2 times longer than those of P2. P4 as long as P2; merus about 1.1 times carapace length; propodus and dactylus as long as those of P3; merocarpal articulation slightly exceeding end of anterior prolongation of article 1 of antennal peduncle ( Fig. 2 G–I).

Remarks. Paramunida aspera , new species, belongs to the group of species with the rostral spine larger than supraocular spines, distomesial spine of antennal article 2 spiniform and mesogastric region with three spines. The new species is morphologically related to P. marionis Cabezas, Macpherson & Machordom, 2010 , but the following characters can distinguish them:

- The number of striae on the thoracic sternite 4 is clearly higher in P. aspera , new species, than in P. marionis . Furthermore, the thoracic sternite 7 is smooth in P. marionis , but with few striae on each lateral side in P. aspera , new species.

- The antennal article 3 is as long as wide in the new species and about 1.5 times longer than wide in P. marionis .

No molecular comparison was performed with P. marionis . The new species is also morphologically allied with P. stichas Macpherson, 1993 , but the distomesial spine of the antennal article 2 is spiniform in P. aspera , new species, and mucronated in P. stichas . Furthermore, the antennal segment 3 is as long as wide in the new species, but 1.5 times longer than broad in P. stichas . The genetic divergence between P. aspera , new species, and P. stichas are in the range of 3.9–5.5% for the ND1 and between 1.5–2.4% for the 16S.

Furthermore, the new species also resembles to P. proxima , but both species can be easily distinguished by the number of mesogastric spines (one in P. proxima versus three in P. aspera , new species) and striae on sternum (numerous striae in P. proxima versus few striae on each side of sternites 5–7 in P. aspera , new species). The genetic divergence between P. aspera , new species, and P. proxima are between 6.6–7.3% for the ND1 and between 1.5–2.4% for the 16S.

Finally, the new species is close related to P. leptotes Macpherson & Baba, 2009 , but they clearly differ in the number of mesogastric spines (three in P. aspera , new species, but one or rarely two in P. leptotes ). Furthermore, the distomesial spine of the antennal article 2 clearly overreaches antennal peduncle in P. leptotes , whereas this spine only slightly exceeds the antennal peduncle in the new species. The genetic divergence between P. aspera , new species, and P. leptotes are in the range of 10.3–10.6% for the ND1 and between 4.3–4.6% for the 16S.

Colour. Body generally pale pinkish orange and covered with numerous fine reddish orange dots. Walking legs, abdominal somites 5–6 and tail fan translucent whitish. Pereopods alternated with orangish red bands. Eyes dark brownish.

Etymology. From the Latin “asper”, which means rough, in reference to the numerous granules and spinules covering the carapace.

Distribution. Philippines, between 357–380 m depth.

Figures

Fig. 2. Paramunida aspera, new species, ovigerous female holotype, 7.9 mm (NMCR). Philippines. A, carapace and abdomen, dorsal view, B, carapace, lateral view; C, thoracic sternum; D, left antennule and antenna, ventral view; E, right maxilliped 3, lateral view; F, right P1, dorsal view; G, right P2, lateral view; H, right P3, lateral view; I, right P4, lateral view. Scale bars = 2 mm.

Fig. 4. A, Paramunida aspera, new species, paratype, Philippines, AURORA 2007 stn CP 2695, paratype male 8.1 mm (NTOU A01409); B, P. crinita Cabezas, Macpherson & Machordom, 2010, Philippines, PANGLAO 2005 stn CP 2344 (NTOU A01353). C, P. proxima (Henderson, 1885), Philippines, PANGLAO 2005 stn CP 2368 (NTOU A01364). D, P. setigera Baba, 1988, Philippines, PANGLAO 2005 stn CP 2340 (NTOU A01389).