Eucalliaxiopsis inaequimana Dworschak, 2014

Poore, Gary, 2021, Indo-West Pacific and Australian species of Eucalliacidae with descriptions of four new species (Crustacea: Axiidea), Memoirs of Museum Victoria 80, pp. 1-41 : 26-28

Eucalliaxiopsis inaequimana Dworschak, 2014

Figures 1h, i , 18 , 25h

Callianassa aequimana .— Poore and Griffin, 1979: 245 (partim from Qld).

Calliax aequimana .— Sakai, 1999: 118–119 (partim from Maldives), fig. 31.

Eucalliax inaequimana Dworschak, 2014: 236–244 , figs 3–7, 9f, g, 10e, f.— Dworschak, 2018: 17.

Eucalliaxiopsis inaequimana .— Poore et al., 2019: 125, 127, fig. 19o, p.— Robles et al., 2020.

Material examined. Papua New Guinea, New Ireland, NW corner of Little Nusa Island , seagrass, 0–1 m, 02° 34.9' S, 150° 46.4' E (KAVIENG 2014 stn KM11 ), MNHN-IU-2013-10006* (female, 5.8 mm), MNHN-IU-2013-10008* (male, 7.2 mm) .

Australia. Qld. Great Barrier Reef, Myrmidon Reef , 18.27° S, 147.38° E, October 1986, 4 m (M. Riddle stn M/10/2), NMV J71689 (2 males, 7.1 mm; 5 females, 5.3–8.3 mm); 2 m (M. Riddle stn M/10/3), NMV J71690 (female, 5.6 mm). Norwest Islet, Capricorn Group, 23.3° S, 151.7° E, AM P.10356 (male, 8.1 mm)

Mariana Islands, Guam, W coast, near Fish Eye Marine Park , sand/rubble flat, 0.2–0.5 m, 13.471° N, 144.704° E (stn AA05), UF 27330 (female, 3.5 mm) .

French Polynesia. Moorea Island , Motu Tiahura / Fareone channel, 17.4888° S, 149.9134° W (stn MIB-225), UF 16512 (male, 5.0 mm). Papetoai, 17.4898°S, 149.884°W, (stn BIZ-463), UF 16479 (female, 3.9 mm), UF 28784 * (male, 5.1 mm); stn BIZ-493 UF 28903 (male, 5.4 mm), UF 28929 (female, 5.1 mm). S of Nihimaru, 17.535° S, 149.904° W (stn BIZ-616), UF 29162 (ovigerous female, 6.6 mm). Off Opunohu public beach, 17.49143° S, 149.85138° W (stn BIZ-636), UF 29208 (male, 6.0 mm). Off Nihimaru river estuary, 17.533° S, 149.9045° W (stn MIB-098), UF 15915 (male, 5.0 mm), UF 15945 (female, 4.0 mm). Gump reef, in front of waterfront bungalows, 17.4902° S, 149.826° W (stn MIB-224), UF 16498 (ovigerous female, 6.2 mm). Between Papetoai and Hotel, 17.4908° S, 149.8871° W (MIB-227), UF 16535 (male, 2.9 mm), UF 16542 (female, 4.6 mm; male, 4.1 mm) .

Diagnosis. Pleonite 1 without pair of sternal plates. Eyestalk about twice as long as wide. Antennule peduncle reaching to base of antenna peduncle article 5. Maxilliped 3 exopod absent. Cheliped carpi distolateral margin square at lower angle, propodi lateral face without longitudinal ridge, upper mesial face with row of short transverse ridges associated with more distal clusters of setae. Male pleopod 1 article 1 linear, with distal setae; article 2 short, oblique, or of single article with narrower distal lobe. Female pleopod 2, appendix interna absent. Uropod endopod ovate. Telson without transverse row of spiniform setae.

Colour. Exoskeleton mostly translucent white, gastric region, distal propodus of chelipeds with few pink chromatophores (fig. 1h, i).

Distribution. Australia, Cocos (Keeling) Island (type locality), Qld, Great Barrier Reef; Papua New Guinea, New Ireland; Indonesia, Sulawesi; Philippines, Panglao; French Polynesia. Intertidal to 4 m.

Remarks. Dworschak (2014) distinguished this species, as Eucalliax inaequimana , on several features including inequality of the chelipeds in both sexes from E. aequimana . Usually, only males of Eucalliaxiopsis have a significantly larger major cheliped although not all descriptions are clear on this point. The same is true of E. patio (described and compared below) and both species differ from E. aequimana in the ways listed by Dworschak (2014).

Robles et al.’s (2020) phylogram detected no genetic difference between two individuals from the type locality, two from Papua New Guinea and one from French Polynesia. Dworschak (2014) recorded the maximum carapace length as 9.1 mm; the largest in this collection were a male of 7.2 mm and ovigerous female of 6.2 mm. His illustrations and description were comprehensive, and many specific details appear on the new material, such as the transverse ridges on the mesial faces of the chelipeds and distal tubercles on the cheliped propodus. A broad postrostral obsolete median ridge defined by shallow longitudinal grooves is typical of the new material (fig. 18a) but was not mentioned by Dworschak (2014). The feature appears to be more conspicuous in some individuals than others (Dworschak, pers. comm. 29 September 2019). The male pleopod 1 is manifest in two forms – a long article and shorter second article (fig. 18b; as figured by Dworschak) – and a form where these appear fused (fig. 18c).

Poore and Griffin’s (1979) specimen of Callianassa aequimana from Queensland was reidentified as E. inaequimana . Sakai’s (1999) record of Calliax aequimana from the Maldives is almost certainly referable to E. inaequimana . Sakai (2018) omitted E. inaequimana from his revision of Eucalliacinae .

Figures

Figure 1. Live colour photographs: a, Calliaxina bulimba, Papua New Guinea. MNHN-IU-2013-7097; b, c, C. kensleyi, Saudi Arabia, UF 36699; d, e, C. novaebritanniae, Papua New Guinea, MNHN-IU-2013-7062; f, Eucalliaxiopsis dworschaki, French Polynesia, UF 16286; g, E. dworschaki, Papua New Guinea, MNHN-IU-2013-7081; h, E. inaequimana, French Polynesia, UF 29162; i, E. inaequimana, French Polynesia, UF 29208. Photos a, d, e, g: Z. Ďuriš; b, c, f, h, i, A. Anker. Various scales.

Figure 18. Eucalliaxiopsis inaequimana. French Polynesia, UF 16512 (male, 5.0 mm): a, anterior carapace, eyestalks, antennule, antenna; b, pleopod 1. French Polynesia, UF 28903 (male, 5.4 mm): c, pleopod 1. Papua New Guinea, MNHN-IU-2014-10008 (male, 7.2 mm): d–f, telson, dorsal, lateral and anterodorsal views. Scale bars a, d–f = 1 mm; scale bars b, c = 0.1 mm.

Figure 25. Eucalliaxiopsis spp. E. aequimana: a, b, major cheliped, mesial. E. dworschaki, Papua New Guinea, MNHN-IU-2013-10003: c, d, major cheliped lateral, upper margin. E. dworschaki, Philippines, NHMW 20923: e, f, major cheliped carpus lower lateral angle, upper margin. E. panglaoensis, NHMW 20922: g, minor cheliped, lateral. E. inaequimana: h, major cheliped, mesial. E. paradoxa: h, i, major cheliped lateral, mesial. Photos e–g: P.C. Dworschak. Various scales.