Chevalia sprightly, Springthorpe & Hughes, 2024

Springthorpe, Roger T. & Hughes, Lauren E., 2024, Re-description of Chevalia aviculae Walker, 1904, five new species and new records of Chevaliidae from Australia and New Zealand (Crustacea: Peracarida: Amphipoda: Senticaudata), Records of the Australian Museum 76 (3), pp. 157-194 : 185-190

Chevalia sprightly sp. nov.

urn:lsid:zoobank.org:act:72D1464C-F77D-4861-9EC9-39F79FFD8F31

( Figs 1–2 , 24–27 )

Holotype: Hermaphrodite “a”, non-ovigerous, 13.3 mm, dissected, 3 slides, AM P.100393, Three Mile Reef, City Beach , Perth , Western Australia, 31°46.817'S 115°40.733'E, 10.5 m, coll. Neville Coleman, 16 March 1972 . Paratypes: hermaphrodite “b”, non-ovigerous, 8.3 mm, dissected, 1 slide, AM P.100394, same location as holotype ; hermaphrodite “c”, ovigerous, 10 mm, dissected, 1 slide, AM P.100395, same location as holotype ; 1 hermaphrodite, ovigerous, 10 mm, 21 hermaphrodites, 8.3–12.5 mm, 32 females, 7.5–12.5 mm, 3 females, ovigerous, 9.2–11.7 mm, 9 immature, 4.2 mm, AM P.100396, same location as holotype ; 1 female, non-ovigerous, 13.3 mm, AM P.100397, 35 km south-west of Cliff Head, Western Australia, 29°40'S 114°42'E, 44 m, coll. RV Sprightly , 17 February 1976, station 17 ; 1 female, 16.7 mm, AM P.100398, south-west of Dongara, Western Australia, 29°49'S 114°24'E, 128–131 m, HMAS Diamantina, CSIRO Fisheries , 11 October 1963, station Dm 6/63/214; 2 hermaphrodites, 10.8–12.5 mm , 1 female, 10 mm, WAM C71210 , north-west of Bluff Point, Western Australia, 27°18'S 113°16'E, 54 fathoms (98 m), Beam Trawl, CSIRO Fisheries , 9 October 1963, station 204 ; 35 males, 5–10 mm, 3 females, ovigerous, 8.3–9.2 mm, 21 females, 5–11.7 mm, 5 juveniles, 4.2–5.8 mm, AM P.100399, south-east of Foul Bay, Western Australia, 35°12' S, 117°00'E, orange-peel grab, coll. HMAS Gascoyne, CSIRO Fisheries , 8 August 1962, station G3/62/160 ; 10 specimens, WAM C71211 , south of Cape Leeuwin, Western Australia, 34°32'S 115°01'E, 73 m, HMAS Gascoyne, CSIRO Fisheries , 9 August 1962, station G3/62/170 .

Additional material examined. Western Australia. Many specimens, AM P.18294, south-east of Foul Bay, 35°12' S, 117°00'E, orange-peel grab, coll. HMAS Gascoyne , CSIRO Fisheries , 8 August 1962, station G3/62/160; 1 hermaphrodite, AM P.18273, north-west of Perth , 30°45'S 114°52'E, 60 m, HMAS Gascoyne, CSIRO Fisheries, 11 August 1962, station G3/62/179 .

Type locality. Three Mile Reef, City Beach, Perth , Western Australia, 31°46.817'S 115°40.733'E .

Etymology. Named for RV Sprightly, in recognition of her great contribution to marine science in Australia.

Diagnosis.Antenna 1 length 0.4 times body length, accessory flagellum 3-articulate. Gnathopod 1 coxa anterodistal corner produced Gnathopod 2 propodus palm transverse, with posterodistal shelf with tooth, distal round excavation, defined by corner with subacute tooth. Pereopods 5–7 merus, carpus and propodus distal margins with numerous long slender plumose setae. Pereopod 7 basis subovate, carpus posterodistal corner with 6 submarginal robust setae. Uropod 2 outer ramus dorsal margin with row of long plumose setae (20+). Uropod 3 rami subequal in length to peduncle. Telson apical margin convex.

Description. Based on holotype, hermaphrodite, non-ovigerous, 13.3 mm, AM P.100393.

Head. Eyes of large size, partially situated in lateral lobe of the head, lateral cephalic lobe subacute. Antennae densely setose. Antenna 1 length 0.4 times body length; peduncular article 1 longer than article 3, primary flagellum with 18 articles; accessory flagellum 3-articulate, article 1 shorter than article 2, article 3 rudimentary. Antenna 2 slightly shorter than antenna 1; article 4 sub-equal in length to article 5; article 5 length 0.7 times flagellum; flagellum with 13 articles. Mandible palp, article 1 less than 0.25 times article 2, article 2 sub-equal in length to article 3; incisor with 5 teeth, lacinia mobilis with 3 teeth, accessory setal row with 3 setae, molar triturative. Lower lip, inner lobes and outer lobes separated, inner lobes large and fleshy. Maxilla 1 inner plate with marginal setae; outer plate with 11 robust setae; palp 2-articulate with 5 apical robust setae and 1 subapical seta. Maxilla 2 inner plate shorter than outer plate, with oblique facial row of plumose setae on outer margin; outer plate with a row of apical plumose setae. Maxilliped inner plate subrectangular, apical margin with 4 robust setae and several plumose setae, medial margin lined with many plumose setae; outer plate sub-equal in length to palp article 2, with 9 robust setae and row of plumose setae on medial and facial margins, with 5 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.

Pereon. Gnathopod 1 coxa larger than coxae 2–4, with anterodistal corner weakly produced, rounded; basis anterior margin concave, posterior margin convex, margins weakly setose; carpus length 3.1 times breadth, carpus 1.2 times propodus length, margins lined with dense setae; propodus length twice breadth, margins lined with dense setae, palm subchelate, convex, palmar margin not defined by corner or robust setae; dactylus closing along palm. Gnathopod 2 basis anterior and posterior margins weakly convex, with few slender setae; carpus length 1.1 times breadth, 0.5 times propodus; propodus subchelate, massive, posterior margin parallel to anterior margin, palm transverse, with posterodistal shelf with tooth, distal round excavation, defined by corner with subacute tooth; dactylus not reaching palm corner. Pereopod 3 oostegite present; basis rectilinear, broad, length 1.8 times breadth; merus rectilinear; carpus length 1.5 times breadth; propodus length 3.3 times breadth. Pereopod 4 oostegite present; basis rectilinear, broad, length 2.1 times breadth; merus rectilinear; carpus length 1.3 times breadth; propodus length 2.8 times breadth. Pereopods 5–7 merus, carpus and propodus distal margins with numerous long slender plumose setae; merus distal corners produced; dactylus anterior margin with accessory spine. Pereopod 5 oostegite present; basis subovate; merus length 1.7 times breadth; carpus length subequal to breadth, posterodistal corner with 6 submarginal robust setae; propodus length 3 times breadth. Pereopod 6 basis subovate, length 1.6 times breadth; merus length 2.3 times breadth; carpus length twice breadth, posterodistal corner with 6 submarginal robust setae; propodus length 3 times breadth. Pereopod 7 basis subovate, length 1.2 times breadth, proximally and distally broad, posterodistal projection absent; merus length 2.6 times breadth; carpus length 1.5 times breadth, posterodistal corner with 6 submarginal robust setae; propodus length 2.8 times breadth.

Pleon. Epimeron 3 posterodistal corner narrowly rounded, without notch. Urosomites 1–2 fused. Uropod 1 peduncle length 1.7 times breadth, 0.6 times outer ramus, dorsal margin with long plumose setae; rami outer margins minutely serrate, inner margins lined with sub-serrate teeth; inner ramus length 10 times breadth, 1.2 times outer ramus, with one apical robust seta; outer ramus outer margin lined with 10 plumose setae, with 4 apical robust setae. Uropod 2 peduncle length 1.1 times outer ramus, 0.8 times inner ramus; inner ramus length 8.2 times breadth, longer than outer ramus, with apical robust seta; outer ramus dorsal margin with row of long plumose setae (20+), apical margin cuticle with 4 teeth and with 4 apical robust setae. Uropod 3 peduncle length 0.9 times breadth, 0.9 times length inner ramus; inner ramus subequal to outer ramus, with long apical plumose setae and one robust seta; outer ramus with long apical plumose setae. Telson with pair of denticular patches, apical margin convex with single pair of plumose setae and a few short plumose setae.

Variation. The gnathopod 1 coxa anterior margin can be either produced or subquadrate to weakly produced (produced, paratype hermaphrodite “c”, AM P.100395; subquadrate to weakly produced, holotype, hermaphrodite “a”, AM P.100393). The gnathopod 2 propodus palm appears to vary with growth stage, with the palm posterodistal shelf becoming more pronounced in larger specimens (8.3 to 13.3 mm, AM P.100393 and AM P.100394, respectively).

Remarks. The shape of pereopods 6 to 7 bases in C. sprightly sp. nov., is ovate, the merus, carpus and propodus have bunches of long, distal plumose setae, the carpus posterodistal corner has 6 submarginal robust setae and uropod 2 outer ramus has a brush of about 20 plumose setae on the outer ramus. This set of characters separate C. sprightly sp. nov. from all other Australian species.

Distribution. Australia. Western Australia: City Beach, Dongara, Bluff Point and Cliff Head, (current study).

Figures

Figure 1. Distribution map of Australian and New Zealand Chevaliidae species. Stars represent type localities; circles represent additional data points.

Figure 2. Field guide to Australian and New Zealand Chevaliidae species.

Figure 24. Chevalia sprightly sp. nov.hermaphrodite ”a”, holotype, 13.3 mm, habitus,AM P.100393, City Beach, Perth, WesternAustralia.

Figure 25. Chevalia sprightly sp. nov., hermaphrodite ”a”, holotype, 13.3 mm,AM P.100393, City Beach, Perth,Western Australia.Scale lines for EP1–3, H represent 0.5 mm, remainder represent 0.2 mm.

Figure 26. Chevalia sprightly sp. nov., hermaphrodite ”a”, holotype, 13.3 mm, AM P.100393, City Beach, Perth, Western Australia; hermaphrodite ”b”, paratype, 8.3 mm, AM P.100394, City Beach, Perth, Western Australia; hermaphrodite ”c”, ovigerous, paratype, 10 mm, AM P.100395, City Beach, Perth, Western Australia. Scale lines represent 0.5 mm.

Figure 27. Chevalia sprightly sp. nov., hermaphrodite ”a”, holotype, 13.3 mm, AM P.100393, City Beach, Perth, Western Australia; hermaphrodite ”c”, ovigerous, paratype, 10 mm, AM P.100395, City Beach, Perth, Western Australia. Scale lines for P5–7 represent 0.5 mm, remainder represent 0.2 mm.