Calliaxina kensleyi ( Dworschak, 2005 )

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 : 6-10

Calliaxina kensleyi ( Dworschak, 2005)

Figures 1b, c , 6 , 7 , 12b, c, i

Eucalliax kensleyi Dworschak, 2005: 205 , figs 1–4, 5a, b.— Sakai, 2017: 1122–1124 (partim), fig. 2A–C, E–G.

Calliaxina kensleyi .— Poore et al., 2019: 125, 127, 146, fig. 19i.

Material examined. Saudi Arabia, Farasan Banks , Marka Island, sandy cay, 18.22055° N, 41.32438° E (stn SAFA-010), UF 36699 (male, 5.9 mm) .

Madagascar, Tuléar (now Toliara), Thomassin stn 648, MNHN- IU-2014-10476 (female, 7.8 mm); Thomassin stn 650, MNHN- IU-2016-8086 (female, 6.6 mm). Nosy Bé, MNHN-IU-2016-8084 (male, 7.4 mm).

Diagnosis. Sternite 7 with transverse groove visible only laterally, anteromedial lobe rounded. Antennule peduncle reaching to midpoint of antenna peduncle article 5. Maxilliped 3 exopod vestigial, about twice as long as wide. Major cheliped merus, lower margin with 2 or 3 proximal truncate teeth; propodus distomesial margin with setae aligned in 2 groups of c. 10 and c. 6 setae. Male pleopod 1 article 2 about 2.5 times as long as wide; appendix interna obsolete.

Colour. Exoskeleton mostly translucent white, gastric region, epistome, upper parts of chelipeds pink (fig. 1b, c).

Distribution. Red Sea ( Jordan, Saudi Arabia); western Indian Ocean ( Madagascar). Intertidal, shallow sediments.

Remarks. Calliaxina kensleyi shares a vestigial maxilliped 3 exopod with C. bulimba . The two species were compared by Dworschak (2005) but the differences he listed are subtle and deserve reinterpretation and addition. The more pronounced rostrum of C. kensleyi is subtly so, but juveniles appear to have sharper rostrum in both species. The telson of C. kensleyi was said to be widest at its midpoint, whereas that of C. bulimba is widest anteriorly; this difference is less obvious in smaller specimens. The uropodal exopod is oval in C. kensleyi , more tapering in C. bulimba , but again less clear in smaller specimens. In both species, the major cheliped (the slightly wider one) has a tooth on the fixed finger, whereas the minor cheliped does not, with the apparent exception of the paratype of C. kensleyi .

Despite their obvious morphological similarity, Calliaxina kensleyi and C. bulimba were not the two most phylogenetically related of the four species in Robles et al.’s (2020) study. Calliaxina kensleyi was sister species to C. novaebritanniae , and these two more related to C. sakaii , which if true suggests that the vestigial maxilliped 3 exopod has evolved twice. Ovoid plates are visible on the sternite of pleonite 1 (fig. 6c) but absent in E. bulimba (fig. 4d).

Dworschak (2005) did not describe the dentition of the lower margin of the merus of the chelipeds of C. kensleyi ; in the new material there are few proximal denticles (fig. 6e, f). All specimens of C. bulimba possess two or three proximal truncated curved teeth and diminishing denticles more distally (fig. 4f). The distomesial face of the propodus of the chelipeds has two rows of submarginal setae in both species. On the major cheliped of C. kensleyi , these setae align in two separate groups of c. 10 and c. 6 setae (figs 6d, 12c); on the minor cheliped, the setae align in two scarcely separate groups of c. 20 and c. 8 setae (fig. 6f; Dworschak, 2005: fig. 3a, c). On both chelipeds of C. bulimba , distomesial setae align in two widely separate groups of c. 9 setae each (fig. 4h). The distolateral propodus of the chelipeds is granulated in a concavity at the base of the fingers in some individuals of both species but is absent on others, especially smaller specimens.

The two males identified here as C. kensleyi possess a male pleopod 1 typical of several species of Calliaxina and Eucalliaxiopsis : C. novaebritanniae , C. paradoxa , C. punica , C. sakaii , Eucalliaxiopsis jonesi ( Heard, 1989), E. mcilhennyi ( Felder and Manning, 1994) and E. panglaoensis (all with a broad article 2, appendix interna and curved apex; see fig. 7h, j and earlier papers ( Dworschak, 2006, 2014; Felder and Manning, 1994; Heard, 1989; de Saint Laurent and Manning, 1982;). As noted above, the male pleopod 1 of C. bulimba differs from all of these, its second article lacking an appendix interna and distal curved apex. The appendix masculina on pleopod 2 of C. kensleyi is narrower than that of C. bulimba .

Sakai (2017) included C. kensleyi in Eucalliax although the species has all the features of Calliaxina , however diagnosed. His figure 2A–C, E–G of material from the Red Sea resembles the types from the nearby type locality, Aqaba. His figure 2D of the cheliped of a female from Ambon has a curiously triangular carpus. The location suggests C. bulimba , a species he did not mention. He referred to E. kensleyi as being from Aqaba and Moreton Bay ( Calliaxina bulimba is from Moreton Bay, Qld) but listed the type locality as Alona

Beach, the Philippines (the type locality of E. panglaoensis Dworschak, 2006 ). The species was not listed by Sakai (2011).

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 6. Calliaxina kensleyi. Madagascar, MNHN-IU-2014-10476 (female): a, anterior carapace, eyestalks; b, thoracic sternite 7; c, pleonal sternite 1 (anterior uppermost); d, e, major cheliped (right), mesial, lateral views, with detail of mesial setae on propodus; f, g, minor cheliped (left), mesial, lateral views, with detail of mesial setae on propodus. Scale bars = 1 mm.

Figure 7. Calliaxina kensleyi. Saudi Arabia, UF 36699 (male): a, anterior carapace, eyestalks, antennule, antenna; b, maxilliped 3, exopod, basis, ischium; c, telson, uropod; d, major cheliped (left), mesial view; e, major cheliped fingers (left), lateral view; f, minor cheliped (right), mesial view; g, minor cheliped fingers (right), lateral view; h, i, pleopods 1, 2. Madagascar, MNHN-IU-2014-8084 (male): j, pleopod 1. Scale bars = 1 mm.

Figure 12. Calliaxina spp. C. bulimba: a, major cheliped, mesial. C. kensleyi: b, c, major cheliped lateral, mesial. C. novaebritanniae: d, major cheliped, mesial; e, minor cheliped, mesial. C. sakaii: f, g, minor cheliped mesial, lateral. Thoracic sterna: h, C. bulimba; i, C. kensleyi; j, C. novaebritanniae. Various scales.