Munida jurunjurun, McCallum & Ahyong & Andreakis, 2021

McCallum, Anna W., Ahyong, Shane T. & Andreakis, Nikos, 2021, New species of squat lobsters of the genus Munida from Australia, Memoirs of Museum Victoria 80, pp. 113-152 : 125-127

Munida jurunjurun sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:CD77DA72-B760-

4983-9252-6BC62CC7CE50

Figures 8 , 9

Type material. Holotype: WAM C78561 , ovigerous female (cl 14.7 mm, pcl 9 mm), Western Australia, off Imperieuse Reef , 17° 35.982' S, 118° 59.076'E to 17° 38.574'S, 119° 01.26'E, 222–319 m, SS05/2007/63, 16 June 2007.

Description. Carapace. Length 1.1 × greatest width, widest at midlength. Dorsal surface with numerous uninterrupted transverse ridges and secondary transverse striae between main ridges; ridges and striae lined with short, non-iridescent setae. Gastric region with 5 pairs of epigastric spines, longest pair behind supraocular spines. Parahepatic, postcervical and dorsal branchial spine present. Anterior part of branchial region between cervical groove and postcervical groove with 3 main ridges; posterior part of branchial region with 6 main transverse ridges (excluding posterodorsal ridge) and 5 secondary striae laterally between main ridges. Cardiac region with 5 main transverse ridges. Intestinal region with transverse ridge, posterodorsal ridge and secondary stria. Frontal margin inclined posteriorly at 112° from midline. Lateral margins slightly convex; anterolateral spines parallel, horizontal, overreaching sinus between rostrum and supraocular spine; small hepatic marginal spine in front of cervical groove (0.15 × length of anterolateral spine); branchial margin with 4 spines. Rostrum spiniform, horizontal, 0.7 × pcl; supraocular spine 0.5 × length of rostrum. Epistomial ridge straight ending slightly anterior to antennal gland; mesial protuberance distinct.

Thoracic sternum. Sternal surface smooth, sternite 4 with few short striae. Sternite 3 0.4 width of sternite 4; midlength of sternal plastron (sternites 4–7) 0.5 width of sternite 7. Sternite 4 anterior margin broadly rounded.

Abdomen. Somite 2 with 2 pairs of small spines at lateral margins of anterior transverse ridge. Somites 2–4 each with 2 or 3 uninterrupted striae behind anterior ridge and some shorter striae. Somite 6 posteromedian margin almost straight. Telson with numerous transverse squamae; greatest width 2.0 × median length; anterolateral margin almost straight or shallowly concave.

Eye. Maximum corneal diameter 0.36 × distance between anterolateral spines.

Antennule. Basal article (distal spines excluded) overreaching or reaching end of corneae; 2 well-developed distal spines, distomesial slightly longer than distolateral; 2 lateral spines, proximal small, distolateral spine exceeding both distal spines.

Antenna. Article 1 with strong distomesial spine overreaching distal margin of article 4. Article 2 with strong distomesial spine overreaching distal margin of article 4; distolateral spine reaching distal margin of article 4; 2 small lateral spines on mesial margin. Articles 3 and 4 unarmed.

Maxilliped 3. Ischium 1.45 × merus length, with strong flexor distal spine; merus with strong spine on flexor margin and small spine distally, with small spine on distal extensor margin.

P1. length 3.0 × pcl, with iridescent setae on inner margin. Merus 1.25 × pcl, with a row of 5 dorsal spines and row of 5 long, close set spines on mesial margin; distal spines strong, distomesial spine not reaching midlength of carpus. Carpus 0.4 × merus length, length 2.6 × width, with spines along mesial and dorsal margins. Propodus 1.1 × merus length, fingers 0.5 × total propodus length, with 2 small distolateral spines; dactylus with small proximal spine small subdistal spine.

P2–4. Long and slender, with numerous scales on lateral surfaces of meri; margins with row of plumose setae and iridescent setae on ischium and merus. P2 length 2.6 × pcl; merus as long as pcl, length 6 × height, 4.0 × carpus length and 1.2 × propodus length, extensor margin spinose, flexor margin with small spine near distal one-fifth and well-developed distal spine; carpus extensor margin with 3 small spines (broken on right P2 of the holotype) and prominent distal spine, flexor margin with distal spine; propodus length 9.3 × height, with 11 small movable flexor spines; dactylus compressed, slightly curved, length 0.5 × propodus length and 5 × height, with 10 evenly spaced spines along distal 0.8 of flexor margin. End of P2 carpus reaching end of P1 merus. P3 with similar spination and article proportions as P2; merus slightly shorter than P2 merus (0.85); propodus and dactylus as long as those of P2. P4 length 0.9 × P2 length; merus 0.7 × pcl, 0.8 × P3 merus length; propodus 0.85 and dactylus 0.95 × length of those of P3; merocarpal articulation slightly overreaching anterolateral corner of carapace.

Genetic data. COI and 16S; see Table 1.

Etymology. Named jurunjurun with the approval of Bardi elders, after Jurun jurun, meaning crayfish in Bardi; used as a noun in apposition.

Remarks. Munida jurunjurun sp. nov. is closest to M. acantha Macpherson, 1994 , from New Caledonia, both species having antennal articles 1 and 2 with long mesial spines overreaching article 4, antennule with distomesial spine longer than distolateral spine, a smooth thoracic sternum, and abdominal somite 2 with small spines limited to the lateral margins of the anterior ridge. The new species differs from M. acantha in having 4 rather than 5 branchial carapace spines. In addition, the new species has a distinct row of spines on the mesial margin of the P1 merus, which are close-set on the distal half of the article, rather than more evenly spaced along the distal 0.6 as in M. acantha . Sequence divergence between M. acantha and M. jurunjurun sp. nov. is 8% for COI and 3.5% for 16S.

Of those species with 4 branchial spines, M. jurunjurun sp. nov. is similar to M. albiapicula Baba and Yu, 1987 , M. zebra Macpherson, 1994 , M. volantis Macpherson, 2004 , and M. nesiotes Macpherson, 1999 , all of which have a long mesial spine on antennal articles 1 and 2. In these species, however, the spines on the anterior ridge of abdominal somite 2 are evenly spread along the entire margin, rather than placed at the lateral extremities.

Distribution. North-western Australia, off Imperieuse Reef, 222–319 m

Figures

Figure 8. Munida jurunjurun sp. nov., holotype, ovigerous female cl 14.7 mm, pcl 9 mm (WAM C78561). A, carapace and abdomen, dorsal view; B, right chela, dorsal view; C, right antenna and antennule, ventral view; D, sternum; E, abdominal somite 6, telson and right uropod. Scale: A–E = 2 mm.

Figure 9. Munida jurunjurun sp. nov., holotype, ovigerous female cl 14.7 mm, pcl 9 mm (WAM C78561): A, right P2 dactylus, lateral view; B, right P2, lateral view; C, right P3, lateral view; D, right P4, lateral view; E, left maxilliped 3, lateral view. Scale A = 1 mm, B–E = 2 mm.