Heteromysis (Olivemysis) murrayae, Daneliya, 2021

Daneliya, Mikhail E., 2021, On the Mysid Crustacean Genus Heteromysis (Mysidae: Heteromysinae) of the Tasman Sea, with Notes on the Tribe Heteromysini, Records of the Australian Museum (Rec. Aust. Mus.) 73 (1), pp. 1-50 : 41-45

Heteromysis (Olivemysis) murrayae sp. nov.

urn:lsid:zoobank.org:act:F0C5B0AA-BCF7-479C-898D-63ECC92011BF

Figs 23−25

Etymology. The species name is dedicated to a polychaete expert Anna Murray, the collector of the holotype and many other mysid specimens, for her contribution to zoology and marine biology.

Holotype. Female (+slide), 7 mm, Twofold Bay, Red Point, 37°06.11'S 149°57.06'E, 13 m, on ascidian Herdmania grandis (as H. momus ), 20 May 1995, coll. A. Murray, st. NSW 1128, by hand on SCUBA (Australian Museum P.98685).

Paratypes. Female, 2 subadults, same as holotype ( AM P.98685); female, 7 mm, Forster, South Bennet Head, 32°11.18'S 152°32.3'E, 7 m, rocky reef with gutters, kelp Ecklonia radiata and sessile invertebrates, encrusted rock overhang, 20°C, 19 Mar 2003, coll. RV Baragula, P. B. Berents, R. T. Johnson, S. J. Keable, S. J. Kiely, A. Murray & R. T. Springthorpe, st. NSW 2176, airlift ( AM P.98687); male, 6.5 mm, 2 females, 7−7.5 mm, Forster, Outer Latitude Rock, 32°12.65'S 152°34.1'E, 13 m, rocky reef with gutters, E. radiata and sessile invertebrates, Herdmania sp. at base of crevice with crab and small bit of orange sponge, 18 Mar 2003, same collectors and gear, st. NSW 2167 ( AM P.98688); subadult female, 5.5 mm, Batemans Bay, west of Tollgate Islands, 35°44.827'S 150°15.42'E, 7.5 m, 22.1C, patches of reef, sand, stones and E. radiata , Herdmania grandis (as H. momus ), 29 Mar 2004, coll. RV Baragula & RV Sula, P. B. Berents, K. Attwood, R. T. Johnson, S. J. Keable, S. J. Kiely, K. Monro, A. Murray and R. T. Springthorpe, J. Watson , st. NSW 2638, by hand on SCUBA ( AM P.98689); male (damaged), 3 females, 7−9 mm, 3 subadult, 8 juveniles, Merimbula, Long Point, southeast of Wharf, 36°54.06'S 149°55.79'E, 12.7 m, on H. grandis (as H. momus ) attached to boulders, 15 May 1995, coll. A. Murray, st. NSW 1053, by hand on SCUBA ( AM P.98690); 2 females, 9−10 mm, 3 subadults, Merimbula Warf, 36°53.92'S 149°55.64'E, 6.6 m, in H. grandis (as H. momus ), 18 May 1995, coll. A. Murray, NSW 1095 ( AM P.98691).

Diagnosis. Rostrum ( Fig. 23A ) angular, apically broadly rounded, reaching proximal part of antennular peduncle segment 1. Eye with cornea narrower than stalk. Eyestalk with distomedial tubercle (without spine). Telson ( Fig. 23B ) about as long as last abdominal segment, 1.1 times as long as wide anteriorly and 0.2 times as wide posteriorly as anteriorly. Telson lateral margins with three to seven anterior and six to nine posterior spiniform setae, with gap between two groups; outer apical spiniform setae rather long, 0.11−0.12 of telson length; inner apical spiniform setae rather short, 0.3−0.4 as long as outer. Telson cleft rather broad and shallow, 0.15−0.20 times telson length, reaching level of one or two last lateral spiniform seta, with 11−15 short spinules, occupying 0.6−0.7 of cleft depth. Antennular segment 2 ( Fig. 23A ) with distomedial flagellated spiniform seta; segment 3 with distomedial inner flagellated spiniform seta about half as long as outer. Antennal scale ( Fig. 23A, E ) reaching middle of antennular peduncle segment 3 and longer than antennal peduncle, 2.4−2.5 times as long as wide. Pereopod 1 ( Fig. 24D ) ischium 1.4−1.5 as long as wide; merus 2.4−2.5 as long as wide and 1.7−1.8 as long as ischium. Carpopropodus of pereopod 1, segment 1 is 2.1−2.3 as long as wide and 0.6−0.7 as long as merus, with two or three pairs of long smooth flagellated posterodistal spiniform setae. Dactylus 0.4 of carpopropodus, with smooth unguis. Carpopropodus of pereopod 2 ( Fig. 24F,G ) is 3-segmented, pereopod 3 ( Fig. 25A ) is 4−5-segmented, pereopods 4−6 ( Fig. 25B,C ) is 7−9 segmented. Pereopod 3−6 unguis serrated ( Fig. 25D ). Male pleopod 3 with 11 flagellated spiniform setae; pleopod 4 ( Fig. 25F ) with 14 flagellated spiniform setae. Uropodal endopod ( Fig. 23D ) with two or three medial spiniform setae in proximal part.

Body length of male 6.5 mm, females 7−10 mm.

Comparison. Heteromysis murrayae sp. nov. is one of the rare cases of species clearly belonging to the subgenus Olivemysis , but lacking the distomedial spine on eyestalk, having instead a tubercle. Another of its rare features is the nearly rounded anterior margin of the carapace, known in the subgenus only in Heteromysis (Olivemysis) xanthops Ii, 1964 , from Japan, a species also lacking the eyestalk spine. This species can be the only likely candidate of a close relation to H. murrayae , and the latter is readily distinguished by the shallower telson cleft (0.15−0.16 of the telson length against 0.26 in H. xanthops ), with fewer spinules (11−15 against 28 in H. xanthops ), the telson lateral spiniform setae along the entire margins and with the gap (in the posterior half in H. xanthops ), the stronger pereopod 1 endopod, with the merus 2.5 as long as wide (3.5−4.0 in H. xanthops ), the carpopropodus segment 1 twice as long as wide (three times as long as wide in H. xanthops ), more flagellated spiniform setae on the male pleopod 4 (14 against seven in H. xanthops ), and less medial spiniform setae on the uropodal endopod (two or three against 14 in H. xanthops ).

Description of holotype. Anterior margin of carapace broadly rounded, covering eyestalk bases. Telson longer than last abdominal somite; 1.1 times as long as wide anteriorly; posterior width 0.24 anterior width. Cleft acuteangular, rather shallow, 0.2 of entire telson length, with 12 spinules, growing ventrally, behind cleft margin. Lateral margins with middle gap: six anterior and six and nine posterior spiniform setae, including two apical. Inner apical spiniform seta rather short, 0.4 times as long as outer. Eye stalks without dorsomedial spine, but clearly anteriorly produced corner in form of tubercle. Cornea narrower than stalk. Antennular peduncle rather strong; segment 2 with distomedial flagellated spiniform seta; segment 3 with two distomedial flagellated spiniform setae, one of them stronger, directed inward, about half as long as another, weaker, directed outward, and two simple setae directed forward. Antennal scale reaching half of peduncle segment 3, its length 2.5 width. Mandibular palp as typical for the genus. Maxilla 1 outer ramus with three caudal setae and about 12 strong spiniform setae. Maxilla 2, exopod with 19 short setae, endopod segment 2 with plumose outer and serrated inner setae. Maxillipeds typical for the genus; maxilliped 1 exopod 8-segmented. Thoracopod exopods 2−5 are 10 segmented. Pereopod 1 endopod, merus 2.6 times as long as wide and 1.8 times as long as ischium; ischium only with medial setae; carpopropodus 2.2 times as long as wide and 0.7 times as long as merus, distomedially with six paired flagellated spiniform setae, and simple long seta at base of each spiniform seta; unguis 1.7 times as long as dactylus. Pereopod 2 merus 1.2 times as long as ischium; carpopropodus 3-segmented, with long setae, 0.7 times as long as merus; segment 1 is 1.2 times as long as segments 2 and 3 together. Pereopod 3 endopod merus 0.7 times as long as ischium, with four bunches of one to three setae; carpopropodus 0.9 times as long as merus; carpopropodus 4-segmented. Pereopod 4−6 ischium 5.7−6.4 times as long as wide, with three or four lateral and three distomedial setae; merus 0.7−0.8 times as long as ischium, with nine or ten groups of one or two setae. Pereopod 3−6 dactylus rather small; dactylary unguis 3.4 times as long as dactylus, serrated; paradactylary setae smooth, sickle-shaped. Pleopod 5 with setae 0.7 times as long as ramus. Uropodal endopod 0.8 the length of exopod, with two medial spiniform setae in proximal part.

Description of male. Pleopods 3 and 4 with 11−14 strong flagellated setae.

Distribution. Australia, New South Wales: Twofold Bay (type locality), Merimbula Bay, Batemans Bay and Forster ( Fig. 22 ).

Habitat. Sublittoral species found at depths of 6.6 to 13 m, in association with ascidian Herdmania grandis (Heller, 1878) or on rocky reef with gutters, Ecklonia radiata and sessile invertebrates, sand and stones.

Figures

Figure 22. Distribution of the Tasman Sea Heteromysis (Olivemysis) species. (A) H. (O.) abrucei and H. (O.) murrayae sp. nov. in the Australian waters (the white sign indicates former record); (B) H. (O.)

Figure 23. Heteromysis (Olivemysis) murrayae sp. nov., holotype, female, 7 mm, AM P.98685. (A) head, dorsal; (B) posterior part of body with telson and uropods, dorsal; (C) posteroventral margin of abdominal segment 6, and uropodal protopod; (D) uropodal endopod, ventral; (E) antennal peduncle and scale, ventral view; (F) mandibular palp, posterior; (G) mandibular palp segment 3, posterior; (H) labrum, ventral; (I) maxilla 1, posterior. Scales (mm): A, B = 1; C−F, H = 0.5; G, I = 0.25.

Figure 24. Heteromysis (Olivemysis) murrayae sp. nov. (A−F) holotype, female, 7 mm, AM P.98685; (G) paratype, female, 7 mm, New South Wales, Forster, AM P.98687. (A) maxilla 2, posterior; (B) maxilliped 1 endopod, posterior; (C) maxilliped 2 endopod, posterior; (D) pereopod 1, posterior; (E) distolateral spiniform setae of pereopod 1 carpopropodus segment 1, posterior; (F) pereopod 2 endopod, posterior; (G) pereopod 2 endopod, posterior. Scales (mm): A, C, D, F, G = 0.5; B, E = 0.25.

Figure 25. Heteromysis (Olivemysis) murrayae sp. nov. (A−E) holotype, female, 7 mm, AM P.98685; (F) paratype, male, 6.5 mm, New South Wales, Forster, AM P.98688. (A) pereopod 3 endopod, posterior; (B) pereopod 4 endopod, posterior; (C) pereopod 6 endopod, posterior; (D) distal part of pereopod 6 endopod, posterior; (E) pleopod 5, anterior; (F) pleopod 4, anterior. Scales (mm): A−C, E, F = 0.5; D = 0.25.