Nedsia douglasi Barnard & Williams, 1995

Bradbury, J. H. & Williams, W. D., 1996, Freshwater amphipods from Barrow Island, Western Australia, Records of the Australian Museum 48 (1), pp. 33-74 : 36-37

Nedsia douglasi Barnard & Williams, 1995

Nedsia douglasi Barnard & Williams, 1995: 198-201.

Diagnosis. Body: only pleonite 6 with 2 dorsal spines. Lateral cephalic lobes strongly projecting. Antennae: ratio of length of peduncular articles of first antenna = 45:35:8. Upper lip: asymmetrical; weakly excavate below. Mandibles: accessory blades (rakers) very few (3- 4), no additional serrations beyond rakers; mandibular palp 2-articulate, ratio of articles 5:8, article-2 linear, subtruncate, 2 or 3 E-setae. Maxillae: inner plates of maxillae 1-2 poorly covered in pubescence; well setose medially; inner plate of maxilla 1 with 6 medial setae, palps symmetric; inner plate of maxilla 2 with no setae other than medial row extending onto face apically. Maxilliped: naked tooth spine of outer plate blunt, palp articles 2-3 weakly setose laterally, setae of article-3 organised into comb rows near base of dactyl; nail of dactyl short. Coxae: 1-7 short; coxae 1-4 lacking posterior spines. Gnathopods 1-2 diverse in female (male unknown): palmar spines of first gnathopod asymmetrically bifid, spines at corner of palm = lateral 3 long, medial 4 short; setae along palm sparse and simple; defining corner of second gnathopod with 1 spine. Gills: coxae 2-4 each with flask shaped gill. Oostegites: present on coxae 2-5. Pleopods: peduncles with 1 seta each; retinaculae = 2, accessory retinaculae = 1. Epimera: posteroventral tooth of epimera 1-3 absent. Uropods: apicolateral corner of peduncles on uropods 1-2 with 1 and 2 spines (thus with 0-1 ventrally displaced spines), dorsal margins spinose, medial margin of uropod 1 with 2 apical spines, all rami of uropods 1-2 with 2 spine rows, albeit weakly furnished; inner ramus of uropod 3 reaching to MO.16 on article-l of outer ramus. Telson : cleft 100%; setal spines, where present, lateral; single lateral penicillate setules at MO.6 on either side.

Description. As recorded for the holotype ( Barnard & Williams, 1995).

A single male specimen was collected from a related site on North West Cape. This specimen, male "c", bears many similarities to the female holotype and is believed to represent the same species. Variations from the holotype are set out within the description below .

Material examined. Male "c", 5 mm: Cape Range, Western Australia. North West Cape region , subterranean fresh waters of the coastal plain. Western Australian Museum sample BESI86. Not from type locality .

Description of male "c" ( Figs 1 , 2 ). Body 5 mm. First antenna: ratio of peduncular articles 50:48:18 (converts to 45:43:16 compared with female type = 45:35:8). Upper lip: apex rounded, not excavate, connection symmetrical. Left mandible: palp article- 1 shorter than 2; article-2 with 2 apical setae; incisor 5 teeth; lacinia mobilis with 4 or 5 teeth; 5 setose accessory blades. Right mandible: incisor with 5 teeth; lacinia mobilis bifid; 4 moderately setose accessory blades. Maxilliped ( Fig. 1 ): 3 blunt naked tooth spines on the inner plate. Gnathopods ( Fig. 2 ): palm of gnathopod 1 more setose than female type, of gnathopod 2 similar. Pereopods ( Fig. 2 ): similar to female type. Uropods: lengths relative to uropod I = 1:0.6:1.6 (vs. 1:0.5: 1.33 in the female type): uropod 1 peduncle 1.14x outer ramus (vs 1.3x); inner ramus 1.14x outer; apices of both rami bearing 4 spines (vs 4-6); uropod 2 rami with marginal spines 1-1 and 1-2 (vs 1-1 and 1-3). Telson : fewer dorsal setae than the female type. Penis: small penial processes borne on either side of the posterior ventral surface of the seventh thoracic segment ( Fig. 1 ).

Distribution. Coastal plain, North West Cape, Western Australia, Western Australian Museum sample BES186.

Figures

Fig. 1. Nedsia douglasi male "e" 5 mm. Maxilliped and penis.

Fig. 2. Nedsia douglasi male "c" 5 mm. Legs.