Paralimnadia rivolensis Brady, 1886

Timms, Brian V., 2019, A redescription of Eulimnadia rivolensis (Brady, 1886) (Branchiopoda: Spinicaudata: Limnadiiidae), and its transfer to Paralimnadia, Memoirs of Museum Victoria 78, pp. 57-64 : 58

Paralimnadia rivolensis Brady, 1886

Figures 1–4

Eulimnadia rivolensis Brady, 1886: 86–67 , fig. D. — Simon, 1886: 456 (list); Spencer and Hall, 1896: 238; Sayce, 1903: 245–246 (text), 248 (synopsis), pl. 32; Wolf, 1911 (list); Dakin, 1914: 295 (list), 300 (text); Gurney, 1927: 60–61, fig. 1A.

Limnadia rivolensis — Daday, 1925: 150 (key), 173–175, fig. 121; Webb and Bell, 1979: 243 (text), table 1; Richter and Timms (text): 348.

Eulimnadia palustera Timms, 2015: 447–449 , fig.6. New synonym

Lectotype. South Australia, hinterland of Rivoli Bay, R. Tate , date unknown but before 1886, BMNH 1890.2 .1.9. Male 9.0 mm long and 6.0 mm high.

Paralectotypes. South Australia, hinterland of Rivoli Bay , R . Tate , date unknown but before 1886, BMNH 1890.2 . 1.10. Male 8.9 mm long and 5.5 mm high; Rivoli Bay , freshwater swamps, 11 November 1882, collector unknown, 4 males, 1 female, NMV J14426 .

Comment. Because the Brady collection in the National Museum Victoria is labelled from Rivoli Bay and has a date that aligns with the approximate date of collection of the lectotype, I believe the two are the contemporaneous. Hence , the collection NMV J14426 are herein designated as paralectotypes, which is convenient given there are no females or eggs among the original syntypes in the British Museum of Natural History .

Other material. Northern Territory: Central Australia, 3 males, 5 females, from Sayce collection but no further data, NMV J54016 ; South Australia; Lake Robe, nearby puddle, Margaret Brock , 23 September 1975, 3 males, 1 female, SAM C12297 ; Snake Lagoon, Kangaroo Island , South Australia, 24 August 1981, D.J. Williams, 4 males, 2 females, SAM C12296 ; Tasmania: no site recorded, R . W. Davis , 18 October 1969, 4 males, 2 females, NMV J46599 ; 4 km north of Campbelltown , 41.93° S, 147.5° E, 24 November 1963, J. Wilson, 1 male, 2 females, AM P55663 ; 4 km north of Campbelltown , 41.93° S, 147.5° E, 20 March 1964, J. Wilson, 7 males, 10 females, AM P55640 ; 1 female, AM P98988 ; 1 male, AM P99519 ; 1 female, AM P99520 ; Coles Bay , 31 December 1964, no collector recorded, 30 males, 42 females and 28 sex uncertain, NMV 54005 ; Campbelltown , 23 October 1965, no collector recorded, 1 female, NMV J46622 ; Bruny Island, between Big Lagoon and Little Lagoon , 21 September 1975, R . B. Manning , 3 males, 4 females, NMV J46600 ; Victoria: Elwood Swamp , 18 July 1899, collector unrecorded, 23 males, 24 females, NMV J53989 ; Elwood, from Sayce collection but no further data but co-types for E. victoriensis Sayce , 4 individuals sex uncertain, NMV J68583 ; Mordialloc , 25 October 1902, collector unrecorded, 1 male, NMV J46622 ; Cheltenham , 22 October 1910, collector unrecorded, 17 males, 25 females, NMV J53987 ; Cheltenham, from Sayce collection but no further data, 4 individuals sex uncertain, NMV J54049 ;

Diagnosis. Egg astroform, projections grooved. First antenna with about 11 lobes, second antenna of about 12 antennomeres. Trunk 18–20 segmented, long palps of claspers with 2–3 palpomeres and palpomere junctions generally inerm. Telson with about 20 dorsal spines, first 3 usually larger and more spaced than others. Cercopod basal section about 60% of total length and bearing about 8 setae of medium length.

Description. Male: Head (fig 1b) with ocular tubercle prominent, the compound eye occupying most (~80%) of it. Rostrum slightly more prominent than ocular tubercle, also slightly asymmetrical and with a rounded apex. Ocellus triangular dorsobasially in rostrum. Frons-rostrum angle about 90°. Dorsal organ posterior to eye by about its half its height, pedunculate about height of ocular tubercle.

First antenna (fig. 1b) distinctly longer than peduncle of second antennae, with 11 lobes, each with numerous short sensory setae. Second antenna (fig. 1d) with a spinose peduncle subequal to length to the rostrum, each flagellum with 11 antennomeres dorsally with 1–2 spines and ventrally with 1–7 longer setae. Basal and distal antennomeres with minimal spines, setae maximal on antennomeres 4–9 and only 1–3 setae on basal 3 antennomeres.

Carapace (fig. 1a) elongated oval, pellucid and with weakly expressed growth lines, numbering about 9. Older growth lines well spaced compared with closer-spaced newer growth lines near carapace margin. Both anterior and posterior angles hardly noticeable.

Twenty pairs of thoracopods, the first two modified as claspers. Claspers (fig. 1f) with palm (endites IV and V) trapezoidal with a slight rounded protrusion distomedially. Apical club (endite IV) rounded with thick denticles distomedially and many spines apicolaterally, moveable finger (endite VI) of normal curved structure and palps of typical structure. Moveable finger terminating in a suctorial disc and distoventrally with many small pits. Long palp (endite V) subequal in length to the palm in the first clasper and about 1.5× longer in second clasper. Short and long palps, both with three palpomeres with junctions between them inerm. Last palpomere the longest, particularly in the second-longest palp. Other thoracopods of typical structure for Eulimnadia , decreasing in size and complexity after 10th thoracopod. Dorsal surface of trunk (fig.1e) with a short spine posteriormedially on each of the 12 posterior trunk segments.

Telson (fig. 1c) with about 20 pairs of dorsal spines, with the first three larger than the next 17, although these generally increase in length posteriorly. Most spines inerm. Caudal filaments originating from a mound a little higher than the dorsal telsonic floor and between the 4th and 5th spine. This dorsal floor posterior to the mound with a moderate declivity then an even slope to cercopod posterior. Cercopod almost as long as the telson dorsum, the basal 60% hardly thinning to a small naked spine, then rapidly thinning to an acute apex. The basal 60% with about 8 short setae dorsolaterally; length of most about basal cercopod diameter, with setae 5thto 7th longest and the last one the shortest). Many tiny denticles dorsolaterally on apical 40% of cercopod. All setae geniculate. Triangular projection beneath the cercopods at the ventroposterior corner of the telson.

Figures

Figure 1. Drawings of types of P. rivolensis, male lectotype BMNH 1890.2.1.9. A, carapace; B head, C, telson and cercopod; D, an antennal flagellum; E trunk segments XIV to XVVII dorsa; F, clasper I with insert of long palp of clasper II; female from paralectotype NMV J14426; G, head; H, telson and cercopod. Scale bars 1 mm.

Figure 2. Digital images of male P. rivolensis from NMV J55640. A, male carapace; B, male head, C, male telson; D, male claspers, E, female head.

Figure 3. Drawings of male and female of P. rivolensis from NMV J55640. A, male carapace; B, male head; C, male antennal flagellum; D, male clasper I, E, male telson; F, female carapace; G, female head; H, female telson. Scale bars 1 mm.

Figure 4. SEM images of eggs of P. rivolensis. A, from type locality Rivoli Bay, SA, freshwater swamps, NMV J14426; B, from Campbelltown Tas, AM P55640; C, from Bruny Island, Tas, NMV J46600; D, from Central Australia, NMV J54016; E, from Flinders Island, Tas, AM P97387; F, swamps from near Lake Muir, WA, WAM C57251