Eucalliaxiopsis aequimana ( Baker, 1907 )

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 : 18-21

Eucalliaxiopsis aequimana ( Baker, 1907)

Figures 13 , 14 , 25a, b

Callianassa aequimana Baker, 1907: 182–185 , pl. 24 figs 1–8.— Hale, 1927: 87, fig. 83.— Poore and Griffin, 1979: 245, figs 12, 13.

Callianassa (Callichirus) aequimana .—De Man, 1928b:28, 93, 114.

Calliax aequimana .—de Saint Laurent and Manning, 1982: 222.— Sakai, 1988: 53, 61.— Sakai, 1999: 118–119 (not fig. 31).— Tudge et al., 2000: 145.— Davie, 2002: 459.— Sakai, 2005: 202. Eucalliax aequimanus .— Poore, 2004: 184, fig.50e, f. Calliaxina aequimana .— Sakai, 2011: 498–499. Eucalliax aequimana .— Dworschak, 2014: 236, 244, figs 8, 9h, i. Bakercalliax aequimana .— Sakai, 2018: 738.

Material examined. Australia. NSW, Balmoral Beach , 33.8° S, 151.3° E, AM P.3636 (male, 20 mm) .

Victoria. San Remo, NW from rock outcrop 1.1 km E of Back Beach Rd ( MRG transect 4), 38.53° S, 145.38° E, NMV J59759 (female, 9.6 mm). San Remo, channel bank end, 38.5233° S, 145.363° E, NMV J59762 (female, 6.6 mm). Port Phillip Bay, Geelong arm, 3 m, ( NMV stn PPBES 953 ), 38.155° S, 144.545° E, NMV J16782 (4 females, 3.4–4.7 mm) .

Tasmania. Waterhouse Island, 3–5 m, 40° 48' S, 147° 38.7' E (Moverley stn 52), NMV J71685 (juv., 2.9 mm). Georges Bay , Steiglitz Beach, 3–4 m, 41° 19.3' S, 148° 19.1' E (Moverley stn 42) NMV J71686 (juv., 2.9 mm) .

South Australia. Port MacDonnell, 38.05° S, 140.7° E, NMV J16783 (male, 12.8 mm). Dutton Bay , eastern shore, 34.0489° S, 136.415° E, NMV J71688 (male, 12.2 mm; 3 females, 8.9–11.9 MM), NMV J59651 * (female, 11.2 mm). NMV J71687 (male, 11.0 mm) .

Western Australia. Houtmans Abrolhos, WAM C9113 (male, 14.8 mm). Dalkeith, Swan River , WAM C1410 (male, 16.2 mm). Colpoy Point , Garden Island , 32° 12' S, 115° 40'E, WAM C11975 (female, 14.4 mm). Rockingham, Point Peron, Cockburn Sound, 32° 11' S, 115° 43'E, WAM C11973 (male, 12.9 mm). Fremantle Harbour, 32° 03' S, 115° 44' E, WAM C12030 (male, 20.3 mm). Mandurah, 32° 32' S, 115° 43' E, WAM C11978 (female, 15.8 mm). Bunbury, 33° 20' S, 115° 38'E, WAM C11990 (female, 10.1 mm). Harbour Board, Bunbury, WAM C5056 (female, 21.3 mm). Koombana Beach, Bunbury, 33° 20' S, 115° 38' E, WAM C12029 (male, 14.9 mm). Leschenault Estuary, Bunbury, 33° 20' S, 115° 38' E, WAM C11986 (male, 11.2 mm). Peel Inlet, 32° 36' S, 115° 43' E, WAM C11968 (male, 8.9 mm; female, 17.6 mm). Albany, 32° 00' S, 117° 52'E, WAM C11994 (female, 13.0 mm). Albany, WAM C6792 (female, 15.9 mm). Cheyne Beach, WAM C11987 (female, 19.8 mm). King George Sound, MNHN Th578 (female) .

Diagnosis. Pleonite 1 with pleopods attached to 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 with oblique longitudinal ridge extending from beyond mid-length of palm on to base of finger, upper mesial face with row of clusters of long setae. Male pleopod 1 article 1 without distal setae, article 2 parallel-sided, apically rounded, with marginal setae, without appendix interna. Female pleopod 2, appendix interna present. Uropod endopod ovate. Telson without transverse row of spiniform setae.

Description of male. Carapace smooth, with pair of shallow longitudinal groove posterior to rostrum; gastric–abdominal regions together 4.3 times as long as wide; branchiostegite calcified, with tessellated pattern of sulci; cervical groove at 0.6 carapace length, scarcely obvious on branchiostegite; cardiac sulcus at 0.76 carapace length, not meeting mid-dorsally, extending transversely across half of branchiostegite, with complex branches dorsally.

Rostrum blunt or obsolete. Anterolateral carapace lobe longer than rostrum, with rounded apex, anteriorly directed, with numerous submarginal dorsal setae.

Thoracic sternite 7 1.15 times as long as wide, with well-defined median sulcus over posterior half, lateral groove anterior to coxal articulation poorly defined, oblique, not meeting medially, with 3 posterolateral clusters of long setae. Pleonal sternite 1with pair of swollen well marked areas anterior to ridge bearing pleopods; without setae. Pleonite 6 lateral margin smooth.

Eyestalks 1.6 times as long as wide at base, tapering around cornea, acute apical tubercle sometimes present; cornea subcircular. Antennular peduncle 2.5 times as long as width of both eyestalks; article 2 2.5 times as long as wide; article 3 0.6 times as long as article 2; articles 2 and 3 with ventrolateral row of long setae, continued onto flagellum. Antennal peduncle 3 times as long as width of both eyestalks, overreaching antennule peduncle by third of article 5; scaphocerite wider than long, subcircular; article 4 c. 5 times as long as wide; article 5 0.6 length of article 4. Maxilliped 3 ischium with slightly convex mesial margin, expanding from narrow proximomesial corner; ischium–merus upper margin 1.5 times as long as greatest width; crista dentata of c. 25 small teeth; carpus–dactylus together almost as long as ischium–merus.

Chelipeds subequal, propodus of major cheliped about 1.2 times that of minor, of similar widths, major dactylus stouter than that of minor. Major cheliped ischium twice as long as distal width, lower margin with short distal tooth; merus 1.8 times as long as broad, lower margin barely convex, unarmed; carpus 1.4 times as wide as upper length, upper margin carinate, distomesial and distolateral margins simple; propodus greatest width proximally, upper palm length 1.1 width, distomesial margin of palm with 2 submarginal groups each of c. 10 setae plus small submarginal bicuspid tooth, distolateral margin of palm with submarginal group of c. 10 setae between fingers plus small submarginal tooth; fixed finger half as long as upper margin of palm, cutting edge with microdenticles over proximal half, obsolete tooth at midpoint, with obsolete lateral ridge extending on to palm; dactylus overreaching fixed finger, 2.2 times as long as width at base, cutting edge sinuous; submarginal tufts of long setae on upper and lower mesial margins of carpus and propodus, opposing mesial margins of fingers.

Minor cheliped ischium twice as long as distal width, lower margin with distal tooth; merus twice as long as broad, lower margin barely convex, unarmed; carpus 1.2 times as wide as upper length, upper margin carinate, distomesial and distolateral margins simple; propodus palm as wide as upper palm length, upper margin carinate, with blunt distal tooth, distomesial margin of palm with 2 submarginal groups of c. 10 and c. 12 setae, distolateral margin of palm with 2 submarginal groups of c. 8 and 10 setae; fixed finger half as long as upper margin of palm, cutting edge smooth, lateral concavity at base of fixed finger sharply defined by ridge on distal palm; dactylus barely overreaching fixed finger, 3.8 times as long as wide at base, cutting edge sinuous; 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 3 times as long as upper margin of propodus. Pereopod 3 merus twice as long as maximum width; carpus 1.6 times as long as wide; propodus with lower margin concave, 1.6 times as long overall as mid-length; dactylus half 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 without distal setae; article 2 parallel-sided, apically rounded, 1.8 times as long as article 1, 4 times as long as wide, apex with c. 10 marginal setae, without appendix interna. Pleopod 2 endopod 2.4 times as long as wide; appendix masculina overreaching endopod by about fifth its length, setose along posterior face and distally; lobe-like appendix interna near midpoint of appendix masculina. Pleopod 3 with appendix interna submerged in endopod margin.

Uropodal endopod anterior margin convex, posterior margin almost straight, widest about third way along, 1.7 times as long as wide, apex broadly rounded, with 2 groups of long setae at ends of anterior and posterior margins; exopod ovate, all margins continuous, greatest dimension 1.3 times greatest width, with row of blade-like distal setae on distal margin; dorsal plate extending beyond half of exopod width, distal margin with spiniform setae. Telson 1.5 times as wide as long, broadest at midpoint, posterolateral corner rounded; posterior margin deeply excavate, with posterolateral cluster of long setae plus short spiniform seta; dorsal surface with sharp transverse ridge at anterior third, notched and with few long setae at midpoint.

Female. Essentially as male except: pleonal sternite 1 with pair of oval plates supporting pleopods, each with longitudinal row of 6–8 single setae emerging from pore. Pleopod 1 peduncle curved, with dense group of plumose setae; article 2 twice as long as article 1.

Distribution. Australia, NSW (as far north as 33° S), Tas., Vic., SA, WA (as far north as 25° S). Intertidal to subtidal sediments.

Remarks. Eucalliaxiopsis aequimana is recognised by the subequal chelipeds that are not sexually dimorphic. In a sample of 14 large specimens, the ratio between the upper propodus margins of major and minor chelipeds ranged from 1.1 to 1.3, with insignificant difference between males and females. The species is notable for the simple setose article 2 of the male pleopod 1, longer than article 1, lacking an appendix interna and acute apex.

The collection from Western Australia includes specimens with carapace lengths ranging 8.9–20.3 mm, most are larger than any from South Australia or Victoria, maximum cl. 12.8 mm. They differ most obviously in the near absence of a prominent rostrum (fig. 13j).

Sakai’s (2005) synonymy includes references to other species from places outside southern Australia.

Figures

Figure 13. Eucalliaxiopsis aequimana. Australia, NMV J71687 (male, 11.0 mm): a, carapace, dorsal view; b, carapace, lateral view; c, d, anterior carapace, eyestalks, antennule, antenna, dorsal and lateral views; e, eyestalk, lateral view; f–h, telson, dorsal, postero-oblique, lateral views; i, right uropod; j, maxilliped 3; k, l, major cheliped (left), mesial and lateral views; m, n, minor cheliped (right), mesial and lateral views. Scale bars = 1 mm.

Figure 14. Eucalliaxiopsis aequimana. Australia, NMV J71687 (male, 11.0 mm): a, b, d, pereopods 2, 3, 5; e, pleonal sternite 1, right pleopod 1(anterior uppermost); g, h, left pleopods 1, 2, posterior views. NMV J759651 (female, 11.2 mm): c, pereopod 4; f, pleonal sternite 1, right pleopod 1; i, left pleopod 1, mesial view; j, k, anterior carapace, antennule, antenna, lateral and dorsal views. 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.