Eucalliaxiopsis dworschaki, Poore, 2021

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 : 21-26

Eucalliaxiopsis dworschaki sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:E8BF2226-256F-

4EF7-9DEB-DFD6955BB744

Figures 1f, g , 15–17 , 25c–f

Eucalliax panglaoensis .— Dworschak, 2006: 356 (partim), fig. 5.— Kneer et al., 2013: 265.— Dworschak, 2018: 17 (partim; not fig. 1 = E. panglaoensis ).

Calliaxina panglaoensis .— Sakai and Türkay, 2014: 191–192, fig. 12.

Eucalliaxiopsis aff. panglaoensis .— Robles et al., 2020.

Material examined. Holotype. Papua New Guinea, New Ireland, NW corner of Little Nusa Island , sand, 0–1 m, 02° 34.9' S, 150° 46.8' E (KAVIENG 2014 stn KM13 ), MNHN-IU-2014-10003* (male, 8.9 mm).

Paratypes. Papua New Guinea. Collected with holotype, MNHN- IU-2017-1351 (female, 8.2 mm). Madang Province, Riwo , mangrove, 05° 09' S, 145° 48.2' E, 1–2 m ( PAPUA NIUGINI stn PR235), MNHN- IU-2013-7081 (female, 7.3 mm) .

French Polynesia, Moorea , Papetoai, near 17.49° S, 149.88° W: stn BIZ-463, UF 28782 * (female, 8.4 mm);stn BIZ-493, UF 28930 (female, 4.4 mm); stn BIZ-539, UF 28878 * (male, 7.9 mm), UF 28877 * (male, 6.0 mm); stn MIB-208, UF 16416 (female, 6.7 mm); stn MIB-195, UF 16286 (male, 8.8 mm); stn MIB-227, UF 16531 (male, 5.4 mm). Off Nihimaru River estuary, 17.533° S, 149.9045° W, stn MIB-098, UF 15946 (male, 2.9 mm) .

Other material. Australia, Qld , Great Barrier Reef, Myrmidon Reef, 18.27° S, 147.38° E, October 1986: lagoon with “ Callianassa ” mounds, 4 m, (M. Riddle stn M/10/2), NMV J71681 (male, 8.4 mm); 8 m, (M. Riddle stn M/10), NMV J71682 (female, 9.2 mm) .

Marianas Island, W coast of Guam, near Fisheye Marine Park, seagrass bed, 0.2–0.5 m (stn AA05), UF GUOK 10-0378, (male, 3.7 mm).

Madagascar, Toliara (as Tuléar), Thomassin stn 678, MNHN- IU-2016-8083 (female, 8.9 mm).

Diagnosis. Pleonite 1 with pleopods attached to pair of sternal plates. Eyestalk about twice as long as wide. Antennule peduncle reaching to midpoint of antenna peduncle article 5. Maxilliped 3 exopod absent. Cheliped carpi distolateral margin with 3 rounded lobes near lower margin separated by submarginal grooves parallel to lower margin, second lobe with slight median depression, propodi lateral face with horizontal longitudinal ridge extending from near carpus to base of finger, upper mesial face with row of clusters of long setae. Male pleopod 1 article 1 linear, with distal setae; article 2 blade-like with subapical medial notch. Female pleopod 2, appendix interna absent. Uropod endopod ovate with excavate apex. Telson with row of spiniform setae on ridge.

Description of holotype male. Carapace length 8.9 mm, smooth; gastric–abdominal regions together 4.7 times as long as wide; branchiostegite fully calcified; cervical groove at 0.60 carapace length, scarcely obvious on branchiostegite; cardiac sulcus at 0.77 carapace length, not meeting mid-dorsally, extending transversely across third of branchiostegite.

Rostrum acute, tapering to narrow tip, length about 0.4 width of eyestalks. Anterolateral carapace lobe almost as long as rostrum, with rounded apex, anteriorly directed, with numerous submarginal dorsal setae.

Thoracic sternite 7 1.2 times as long as wide, with well-defined median sulcus over posterior half, lateral groove anterior to coxal articulation well defined, oblique, meeting medially, with 3 posterolateral clusters of long setae. Pleonal sternite 1 with pair of swollen relatively unchitinised areas anterior to ridge bearing pleopods; without setae. Pleonite 6 with small lateral blunt hook-like process at midpoint.

Eyestalks twice as long as wide at base, tapering to cornea and acute apical tubercle; cornea subcircular. Antennular peduncle 3 times as long as width of both eyestalks; article 2 3.5 times as long as wide; article 3 half as long as article 2; articles 2 and 3 with ventrolateral row of long setae, continued onto flagellum. Antennal peduncle 3.4 times as long as width of both eyestalks, overreaching antennule peduncle by most of article 5; scaphocerite wider than long, with acute apex; article 4 c. 5 times as long as wide; article 5 0.65 length of article 4. Maxilliped 3 ischium with slightly convex mesial margin, expanding from narrow proximomesial corner; ischium–merus upper margin 1.6 times as long as greatest width; crista dentata of 12 spines, the most proximal reflexed; carpus–dactylus together almost as long as ischium–merus.

Chelipeds unequal, of similar lengths, propodi of similar widths, major dactylus stouter than that of minor. Major cheliped (left in holotype) ischium twice as long as distal width, lower margin with short spines becoming more distinct distally; merus 1.8 times as long as broad, lower margin mostly straight, unarmed; carpus 1.4 times as wide as upper length, upper margin carinate, with proximal hooked tooth, subproximal mesial pit, distal tooth, distomesial margin with prominent lobe near lower margin, distomesial face with lower submarginal ridge, distolateral margin with rounded notch near upper margin, with 3 rounded lobes near lower margin separated by submarginal grooves parallel to lower margin, second lobe with slight median depression, 2 short setae in lower groove; propodus greatest width in middle of palm, upper palm length equal to greatest width, upper margin carinate, with rounded lobe projecting over dactylus, lower margin carinate, strongly curved mesially, mesial face with short distal uneven setose ridge below upper margin, distomesial margin of palm almost straight, lateral face of palm with prominent ridge running from tubercle near proximal margin on to finger, oblique row of tubercles at proximal end of ridge, each perforated for cluster of setae; fixed finger half length of upper margin of palm, cutting edge with denticles over proximal half, blunt triangular tooth at about midpoint; dactylus as long as fixed finger, twice as long as wide at base, cutting edge with blunt molar, with deflected tip; submarginal tufts of long setae on upper and lower mesial margins of carpus and propodus, opposing mesial margins of fingers.

Minor cheliped (right in holotype) ischium twice as long as distal width, lower margin with distal spine; merus 1.7 times as long as broad, lower margin mostly straight, unarmed; carpus 1.4 times as wide as upper length, upper margin carinate, with proximal hooked tooth, subproximal mesial pit, distal tooth, distomesial face with lower submarginal ridge, distolateral margin with notch near upper margin, with 3 lobes near lower margin separated by perpendicular submarginal grooves, middle lobe apex rounded, with shallow median groove, 3 short setae in lower groove; propodus greatest width in middle of palm, upper palm length equal to greatest width, as wide distally as proximally, upper margin carinate, overhanging mesial face, with rounded lobe projecting over dactylus, lower margin carinate, strongly curved mesially, distomesial margin of palm almost straight, lateral face of palm with prominent ridge running from tubercle near proximal margin on to finger, oblique row of tubercles at proximal end of ridge, each perforated for cluster of setae; fixed finger 0.7 length of upper margin of palm, width at base half width of palm, cutting edge smooth; dactylus as long as fixed finger, 3.5 times as long as wide at base, cutting edge straight; submarginal tufts of long setae on upper and lower mesial margins of carpus and propodus, opposing mesial margins of fingers.

Pereopod 2 merus twice as long as maximum width; dactylus c. 2.5 times as long as upper margin of propodus. Pereopod 3 merus 2.2 times as long as maximum width; carpus 1.8 times as long as wide; propodus with lower margin concave, 1.5 times as long overall as mid-length; dactylus 0.7 times length of axial length of propodus. Pereopod 4 merus length 2.7 times maximum width; carpus 2.7 times as long as wide; propodus 1.5 times as long as wide, typically setose, with 1 long distal seta overlapping dactylus.

Pleopod 1 article 1 distally setose; article 2 as long as article 1, 4 times as long as wide, with apex curved over subdistal notch, appendix interna freely produced, unarmed. Pleopod 2 endopod 2.1 times as long as wide; appendix masculina overreaching endopod by about half its length, setose along posterior face and distally; appendix interna near base of appendix masculina with 5 small hooks. Pleopod 3 with appendix interna submerged in endopod margin.

Uropodal endopod anterior margin convex, posterior margin convex, widest about third way along, 1.4 times as long as wide, apex excavate, with rows of long setae at ends of anterior and posterior margins, with 11 short setae between in excavation, with subdistal group of facial setae; exopod ovate, anterior margin straight, distal and posterior margins continuous, greatest dimension 2.3 times anterior margin, with row of blade-like distal setae on distal margin, c. 6 not overlapping with densely setose distal margin; dorsal plate extending almost half of exopod width, distal margin with spiniform setae. Telson 1.8 times as wide as long, broadest at midpoint, posterolateral corner squarish; posterior margin sinuous, lateral regions most prominent, with posterolateral cluster of long setae plus 2 short spiniform setae; dorsal surface with sharp transverse ridge at anterior third, with 30 short spiniform setae, few long setae at midpoint.

Female. Essentially as male except: major cheliped palm more tapering than in male, widest proximally. Pleonal sternite 1with pair of oval plates supporting pleopods, each with longitudinal row of c. 20 setae in clusters of 4 or 5. Pleopod 1 peduncle with mesial setose lobe longer than base. Pleopod 2 peduncle with similar lobe directed mesially.

Colour. Exoskeleton mostly translucent white, upper parts of chelipeds pink (fig. 1f, g).

Etymology. For Peter C. Dworschak, good friend and colleague, and in recognition of his career devoted to the biology of “thalassinideans”.

Distribution. Madagascar, Philippines, Mariana Islands, Papua New Guinea, Indonesia, French Polynesia. Intertidal to 8 m.

Remarks. Eucalliaxiopsis dworschaki is similar to E. panglaoensis and E. paradoxa (see remarks under Eucalliaxiopsis above). Eucalliaxiopsis dworschaki differs from both species in possession of a proximal hooked spine and subproximal-mesial pit on the upper margin of the carpus of both chelipeds (figs 16g, 25d, e) and a lateral ridge extending almost the entire length of the propodus of both chelipeds (figs 16b, 25b). The palm of the major cheliped of the male is a little longer than wide, while it is 1.25 times as long as wide in E. panglaoensis . The telson is relatively shorter (length: width ratio 1.8 vs 1.6) and with a more sinuous posterior margin, and the uropodal endopod is broader (length: width ratio 1.4 vs 1.6). Dworschak (2006; pers. comm. 29 September 2019) reported a small spine on the merus of maxilliped 3 of the allotype of E. panglaoensis , and of seven from Sulawesi, here reidentified as E. dworschaki . None of the material examined for this study, nor Dworschak’s two individuals from Bali, possess this spine. Eucalliaxiopsis paradoxa is compared below.

Dworschak (2006: 356, fig. 5) remarked on and illustrated two females from Panglao that differed from typical E. panglaoensis . He noted the hook and pit on the upper margin of the cheliped carpus and the longitudinal ridge on the propodus, characters used here to differentiate E. dworschaki . The genetic difference from E. panglaoensis from the type locality in the Philippines ( Robles et al., 2020) and consistent morphology of E. dworschaki over a wide geographic range in the Indo-West Pacific support recognition of two species. Dworschak (2018) listed material of E. panglaoensis from Sulawesi and Bali, Indonesia. He has now confirmed (pers. comm. 30 October 2018) that this collection of five males and four females also belongs to E. dworschaki . The two species occur sympatrically at Panglao and a single individual of E. dworschaki was recorded from Guam, not far from the Philippines. A large sample of ghost shrimps from the Great Barrier Reef, a sample that included specimens of Corallianassa sp. ( Callichiridae ) and Thomassinia aimsae Poore, 1997 ( Callianideidae ), was dominated by E. paradoxa but also included one specimen of E. dworschaki .

There is no genetic difference between the individual from Papua New Guinea and the three sequenced from French Polynesia.

Sakai and Türkay (2014) illustrated a single somewhat distorted individual from Papua New Guinea that was identified as Calliaxina panglaoensis . On the basis of its recorded locality, the specimen is probably E. dworschaki .

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 15. Eucalliaxiopsis dworschaki sp. nov. Holotype, MNHN-IU-2014-10003 (male, 8.9 mm): a, b, carapace, pleonite 1, dorsal and lateral views; c, d, anterior carapace, eyestalks, antennule, antenna, dorsal and lateral views; e, thoracic sternite 7; f, pleonite 1, sternite (anterior uppermost); g, pleonite 6, right lateral margin, oblique view; h, i, maxilliped 3; j, maxilliped 3, crista dentata; k, left uropod; l, m, telson, dorsal and lateral views. Scale bars = 1 mm.

Figure 16.Eucalliaxiopsis dworschaki sp. nov. Holotype, MNHN-IU-2014-10003 (male, 8.9 mm): a, b, major cheliped (left), mesial and lateral views; c, d, major cheliped (left), carpus, propodus, dactylus, upper and lower views; e, f, minor cheliped (right), mesial and lateral views; g, h, minor cheliped (right), carpus, propodus, dactylus, upper and lower views; i–l, pereopods 2–5; m, right pleopod 1, mesial view; n, right pleopod 2, anterior view; o, appendices masculina, interna, posterior view; p, right pleopod 3, posterior view. UF 28877 (male, 6.0 mm): q, pleopod 1. Scale bars = 1 mm.

Figure 17. Eucalliaxiopsis dworschaki sp. nov. Paratype, MNHN-IU-2017-1351 (female, 8.2 mm): a, b, major cheliped (right), mesial and lateral views; c, carpus, lower distolateral margin, detail; d, e, minor cheliped (left), mesial and lateral views; f, carpus, lower distolateral margin, detail; g, pleonite 1; h, pleonal sternite 1, left pleopod 1 in situ (anterior uppermost); i, left pleopod 1, anterior view; j, k, left pleopod 2, posterior view, lateral view of peduncle. Scale bars = 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.