Paramunida christinae, Mccallum, Anna W., Cabezas, Patricia & Andreakis, Nikos, 2016

Mccallum, Anna W., Cabezas, Patricia & Andreakis, Nikos, 2016, Deep-sea squat lobsters of the genus Paramunida Baba, 1988 (Crustacea: Decapoda: Munididae) from north-western Australia: new records and description of three new species, Zootaxa 4173 (3), pp. 201-224 : 206-209

Paramunida christinae sp. nov.

( Fig. 2A , 3)

Material examined. Holotype: NMV J67668 , male (cl 11.6 mm), north-western Australia, SS05/2007 120, 16°36.318'S, 120°34.476'E to 16°37.14'S, 120°34.02'E, 407–414 m, 30 June 2007 .

Paratypes: NMV J56024 , 4 ovigerous females (cl 11.3–11.6 mm), 1 female (cl 7.6 mm), 2 males (cl 9.6 mm, 1 male with parasitic bopyrid isopod), north-western Australia, same data as holotype . NMV J56021 , 7 ovigerous females (cl 10.9–13.2 mm), 1 female (cl. 13.2 mm), 8 males (9.2–13.4 mm), north-western Australia, SS05/2007 175, 13°15.552'S, 123°22.566'E to 13°14.616'S, 123°22.734'E, 405– 404 m, 5 July 2007 . NMV J56020 , 1 male (cl 11.7 mm), 2 females (cl. 8.4–10.7 mm), north-western Australia, SS05/2007 180, 13°15.9'S, 123°22.446'E to 13°16.35'S, 123°21.408'E, 394– 390 m, 5 July 2007 . NMV J56023 , 7 males (cl 7.5–12.1 mm), 4 females (cl. 9.0– 11.9 mm), north-western Australia, SS05/2007 78, 17°11.868'S, 119°33.654'E to 17°12.75'S, 119°33.474'E, 439– 412 m, 18 June 2007 .

Description. Carapace: As long as broad. Spinules on gastric and hepatic regions arising from scale-like striae and with few short uniramous setae. Epigastric region with two spines, each behind supraocular spine; without median row of spinules behind rostral spine. Mesogastric region with 1 well-developed median spine. Anterior branch of cervical groove with short setae. Cervical groove distinct. Cardiac and anterior branchial regions slightly circumscribed. Cardiac region with a row of 4 or 5 spines in midline, third one stronger and thicker than all others; second spine much smaller than first. Posterior margin of the carapace preceded by ridge with well-developed spine and numerous spinules. Each branchial region with row of 3 spines near cardiac region. Frontal margin slightly concave. Lateral margins convex, with row of spines and iridescent setae on anterior half. Anterolateral spine well developed, exceeding or reaching sinus between rostral and supraocular spines. Rostral spine spiniform, upwardly directed, larger than supraocular spines, with thin dorsal longitudinal carina; margin between rostral and supraocular spines slightly concave ( Figs. 3 A, B).

Sternum: Thoracic sternites 4 with few short arcuate striae medially; and sternites 5–7 with few striae on each lateral side ( Fig. 3 C).

Abdomen: Somite 2 slightly narrower than carapace, 0.95 times the breadth of the carapace. Somites 2–3 each with 4 well-developed spines on anterior ridge, 2 median spines on posterior ridge. Somite 4 with 4 spines on anterior ridge; single median spine on posterior ridge. Anterior ridges with numerous spinules and a few small spines ( Fig. 3 A)

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

A

D F E

G

H I B C a,b,c 5mm

d,e 2mm

f,g,h, i 5 mm Antennule: Article 1 slightly exceeding corneae, with distomesial spine small and 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. 3 D).

Antenna: Anterior prolongation of article 1 overreaching antennular article 1 by about one-fourth of its length. Article 2 about twice as long as article 3 and 1.6 times longer than wide, ventral surface with few scales; distomesial spine spiniform, without tuft of setae, almost reaching midlength of anterior prolongation of article 1, almost reaching or exceeding distal end of article 3; distolateral spine not reaching end of article 3. Article 3 nearly 1.5 times longer than wide and unarmed ( Fig. 3 D).

Mxp 3: Ischium about twice 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. 3 E).

P1: Long and slender, squamate, 4.7–5.7 times carapace length; carpus as long as palm, 6.8–7.8 times longer than high; palm 1.1–1.2 times finger length. Base of carpus without bundle of setae ( Fig. 3 F).

P2–4: Long and slender, with numerous scales on lateral sides of meri, carpi and propodi; scales with short setae. P2 3.1–3.6 times carapace length, merus 1.3–1.6 times longer than carapace, about 10–11 times as long as high, 3.3–3.7 times as long as carpus and 1.6 times as long as propodus; propodus 6.7–7.9 times as long as high, 1.3–1.5 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; row of small spines along flexolateral margin. Carpus with some small extensor marginal spines, distal spine on extensor and ventral flexor margin. Propodus with small movable flexor spines. Dactylus compressed, slightly curved, with longitudinal carinae along mesial and lateral sides, ventral flexor border unarmed. End of P2 carpus not reaching end of P1 merus. P3 with similar spination and article proportions as P2; merus slightly shorter than P2 merus; propodus and dactylus as long as those of P2. P4 as long as P2; merus 1.3–1.6 times carapace length; propodus and dactylus as long as those of P3; merocarpal articulation exceeding end of anterior prolongation of article 1 of antennal peduncle ( Figs. 3 G–I).

Etymology. For Christina , daughter of N. Andreakis.

Colour in life ( Fig. 2A ). Carapace, abdomen, and P1–5 translucent white. Third cardiac spine red. Posterolateral margin with red markings. Base of rostrum and supraocular spines, anterior part of posterior branchial region, and posterior cardiac region orange. P1–5 with orange-red bands and spots.

Remarks. This species is very similar to Paramunida polita , which is known from Indonesia and the Philippines ( Macpherson 1993; Cabezas et al. 2010). The new species can be distinguished from P. polita by the presence of a distinctive third cardiac spine, which is always stronger and thicker than the first cardiac spine, and coloured red. The red colour of the spine is still visible in ethanol preserved material eight years after it was collected. A number of specimens of P. polita collected from Indonesia and housed in the Muséum national d’histoire naturelle, Paris (MNHN) were examined by Enrique Macpherson at our request who confirmed that in P. polita the first cardiac spine is always subequal to the third. We could find very few other characters to distinguish the two species. In all our specimens the third maxilliped has a single spine on the flexor margin of the merus, whereas the Indonesian holotype of P. polita has two spines.This character, however, shows intraspecific variation as other Indonesian specimens of P. polita had either 1 or 2 spines (E. Macpherson pers com.). The distomesial spine of antennal article 2 is variable in the new species; in some specimens the spine does not exceed the distal end of article 3, and in others it is exceeding. The molecular data confimed that P. christinae sp. nov. is a distinct species from P. polita although the species are close (divergence of 0.014). Despite the similarity, we consider that the distinctive and consistently larger cardiac spine is a useful and valid character to separate the species. Its distinctive colour pattern may also be useful in distinguishing the species if more information on the colour of P. polita becomes available in the future.

Distribution. Western Australia; 200– 502 m.

Figures

FIGURE 2. A, Paramunida christinae sp. nov. unspecified specimen (NMV J 56023); B – C, Paramunida tricarinata (Alcock, 1894), female, cl 14.2 mm (NMV J 56012), male, cl 5.10 mm (NMV J 56017). Photos: K. Gowlett-Holmes.