Chevalia bardi, 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 : 169

Chevalia bardi sp. nov.

urn:lsid:zoobank.org:act:88E6D63C-830A-4C7B-BB08-149E4F064D3D

( Figs 1–2 , 11–13 )

Holotype: Female, ovigerous, 20 mm, dissected, (carcass and 4 slides), AM P.100381, about 90 km west of Dongara , Western Australia, ca. 29°S 114°E, ca. 100 m, RV Sprightly, 10 November 1976, station 31.

Type locality. About 90 km west of Dongara , Western Australia, ca. 29°S 114°E .

Etymology. ‘Bardi’ from the regional Aboriginal name for the witchetty grub, in reference to the general impression and size of the species in comparison to other known species of Chevalia ; used as a noun in apposition.

Diagnosis. Antenna 1 length 0.2 times body length, accessory flagellum 3-articulate. Gnathopod 1 coxa with anterodistal corner weakly produced, rounded. Gnathopod 2, propodus palm oblique or transverse, with posterodistal shelf, with distal round excavation, defined by corner with subacute tooth. Pereopods 5–7 merus, carpus and propodus distal margins without long slender plumose setae. Pereopod 7 basis subovate, carpus posterodistal corner with 5 submarginal robust setae. Uropod 2 outer ramus dorsal margin with row of 9 long plumose setae. Uropod 3 rami shorter than peduncle inner ramus shorter than outer ramus. Telson apical margin convex.

Description. Based on holotype female, ovigerous, 20 mm, AM P.100381.

Head. Eyes of large size, partially situated in lateral lobe of the head, lateral cephalic lobe rounded.Antennae moderately setose. Antenna 1 length 0.2 times body length; peduncular article 1 longer than article 3; primary flagellum with 9 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 subequal to flagellum; flagellum with 6 articles. Mandible palp article 1 less than 0.4 times article 2, article 2 sub-equal in length to article 3; incisor with 4 teeth, lacinia mobilis with 4 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 9 robust setae; palp 2-articulated with 6 apical robust setae and 4 subapical setae. 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 7 robust setae and row of plumose setae on medial and facial margins, with 3 apical plumose setae; palp, article 2 longer than articles 3 and 4 combined, article 4 with 1 long distal seta.

Pereon. Gnathopod 1 coxa subequal to coxae 2–4, with anterodistal corner weakly produced, rounded; basis anterior margin concave, posterior margin convex, margins setose; carpus length 1.9 times breadth, 1.2 times propodus length, margins lined with dense setae; propodus length 1.9 times breadth, margins lined with dense setae, subchelate, straight, palmar margin defined by corner without robust setae; dactylus slightly overreaching palm. Gnathopod 2 oostegite present; basis anterior and posterior margins straight, with few slender setae; carpus length subequal to breadth, 0.6 times propodus; propodus subchelate, massive, posterior margin parallel to anterior margin, palm oblique to transverse, with posterodistal shelf, distal round excavation, defined by corner with subacute tooth; dactylus reaching palm corner. Pereopod 3 oostegite present; basis rectilinear, broad, length 2.5 times breadth; merus rectilinear; carpus length subequal to breadth; propodus length 1.9 times breadth. Pereopod 4 oostegite present; basis rectilinear, broad, length 1.9 times breadth; merus rectilinear; carpus length 1.1 times breadth; propodus length 2.2 times breadth. Pereopods 5–7 merus, carpus and propodus distal margins without long slender plumose setae; merus distal corners produced; dactylus anterior margin with accessory spine. Pereopod 5 oostegite present; basis subovate; merus length subequal to breadth; carpus length subequal to breadth, posterodistal corner with 4 submarginal robust setae; propodus length 2.1 times breadth. Pereopod 6 basis subovate, length 1.4 times breadth; merus length 1.2 times breadth; carpus length subequal to breadth, posterodistal corner with 4 submarginal robust setae; propodus length 2.4 times breadth. Pereopod 7 basis subovate, length 1.4 times breadth, proximally broad and distally narrow, posterodistal projection absent; merus length 1.3 times breadth; carpus length 1.3 times breadth, posterodistal corner with 5 submarginal robust setae; propodus length 2.1 times breadth.

Pleon. Epimeron 3 posterodistal corner without notch. Urosomites 1–2 fused. Uropod 1 peduncle length 1.1 times breadth, 0.6 times outer ramus, dorsal margin with long plumose setae; rami outer margins minutely pectinate, inner margins lined with sub-serrate teeth; inner ramus length 7.9 times breadth, 1.3 times outer ramus, with 4 apical robust setae; outer ramus outer margin lined with 6 slender setae, with 4 apical robust setae. Uropod 2 peduncle length 0.9 times outer ramus; inner ramus length 6.7 times breadth, 1.1 times outer ramus, without robust setae; outer ramus dorsal margin with row of 9 long plumose setae, apical margin cuticle with 3 teeth and with 4 apical robust setae. Uropod 3 peduncle length subequal to breadth, 2.3 times length inner ramus; inner ramus 0.7 times outer ramus, with long apical plumose setae, without robust seta; outer ramus with long apical plumose setae. Telson with pair of minute apical robust setae, apical margin convex with 3–5 pairs of plumose setae and a few short plumose setae.

Remarks. Chevalia bardi sp. nov. can be differentiated from C. burrewarra sp. nov., C. csiro sp. nov., C. freycinet sp. nov. and C. sprightly sp. nov. by the presence of many setae on the basis of gnathopod 2. In C. bardi sp. nov. the gnathopod 1 basis has convex margins while the gnathopod 2 basis margins are straight separating it from other species (in this study) where the gnathopod bases have a similar shape. Chevalia bardi sp. nov. can be separated from C. csiro sp. nov. by the subovate bases of pereopods 5 to 7 whereas C. csiro sp. nov. has subrectangular bases. Chevalia bardi sp. nov. has a much larger body size, 20 mm, than C. csiro sp. nov., 5.8 mm, with which it co-occurred.

Distribution. Australia. Western Australia: west of Dongara (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 11. Chevalia bardi sp. nov., female ovigerous, holotype 20 mm, AM P.100381, west of Dongara, Western Australia. Scale lines represent 0.2 mm.

Figure 12. Chevalia bardi sp. nov., female ovigerous, holotype 20 mm, AM P.100381, west of Dongara, Western Australia. Scale lines for U2, U3, T represent 0.2 mm, remainder represent 0.5 mm.

Figure 13. Chevalia bardi sp. nov., female ovigerous, holotype, 20 mm, AM P.100381, west of Dongara, Western Australia. Scale lines represent 0.5 mm.