Eulimnadia beverleyae, Brian V Timms, 2016

Brian V Timms, 2016, A partial revision of the Australian Eulimnadia Packard, 1874 (Branchiopoda: Spinicaudata: Limnadiidae), Zootaxa 4066 (4), pp. 351-389 : 361-363

Eulimnadia beverleyae sp. nov.

( Figs 3 F,6)

Etymology. This species is named for my wife, Beverley Timms who is tolerant of my long absences in the field, laboratory and office.

Type locality. New South Wales, Paroo district, Bloodwood Station, 125 km NW of Bourke, an intermittent grassy pool 1.37 km S of the Shearing Shed, 29o 32’ 11.01”S, 144o 51’ 15.58”E, 21 January 2011, BVT.

Type material. Holotype. Male deposited in Australian Museum, length 5.4 mm, height 3.8 mm, registration number AM P97806.

Allotype. Female deposited in Australian Museum, length 6.0 mm, height 4.0 mm, registration number AM P97807.

Paratypes. Two females, 6.0 x 4.2 mm, 6.1 x 4.3 mm, deposited in Australian Museum, registration number AM P97808.

Diagnosis. Egg spherical, surface with about 30 rounded ridges and grooves and no protrusions. Each groove about 25% of egg diameter. Cercopod with about 11–13 long setae on basal 75%; about 11–13 telsonic spines and caudal filaments arising from about the 2nd to 3rd spine. Clasper with 5 uneven spines at palpomere junction plus a similar set midway on lateral surface of basal palpomere.

Description. Egg. ( Fig 3 F). Spherical, diameter 158–175 Μm (n = 5), with about 30 (range 25–34) sets of grooves and rounded ridges, each groove about 40 Μm, i.e about 25% of egg diameter (35–54 ìm, n = 30). No protrusions. Tertiary layer spongiform and surface microporous.

Male. Head ( Fig 6 C) with ocular tubercle prominent, the compound eye occupying most (ca. 80%) of it. Rostrum about 1.5x ocular tubercle, symmetrical, with a rounded apex and with the ocellus dorsocentrally. Fronsrostrum angle ca.100o. Dorsal organ posterior to eye by about its height, pedunculate and about 0.75 height of ocular tubercle.

First antenna distinctly longer than peduncle of second antennae, and with about ten lobes, each with numerous short sensory setae.

Second antenna with a spinose peduncle and each flagella with 8 antennomeres, dorsally with 1–4 short spines and ventrally with 1–5 longer setae. Basal and distal segments with minimal spines, though setae maximal on distal antennomeres.

Carapace ( Fig 6 A) elongated oval, pellucid and with slight indication of three growth lines. Adductor muscle scar at about 45o to the horizontal axis.

Thoracopods. Eighteen pairs. The first two modified as claspers ( Fig 6 F). Claspers with palm trapezoidal, apical club rounded with thick denticles distomedially and spines apicolaterally, movable finger of normal curved structure, often with a 1–4 spaced dorsal spines. Palps of typical structure. Long palp subequal in length to the palm in first clasper and about 1.5 times longer in second clasper. Both two segmented with about 5 unequal spines at their junctions. Each with five spines, again subequal in length, mediolaterally on the basal palpomere. The three medial most spines of each group subequal in length to palpomere width, next spine about 2x palpomere width, and most lateral spine 2.5 times in first clasper and 3.5 times in second clasper of palpomere width. Other thoracopods of typical structure for Eulimnadia , decreasing is size and complexity posteriorly. Dorsal surface of trunk with 1–2 short spines medially or posteriorly on each of the posterior 12 trunk segments.

Telson ( Fig 6 E) with about 12–13 pairs of dorsal spines, with a distinct space after the 3rd spine and a slight progressive increase in size among distal spines. Many spines with a few denticles. Caudal filaments originating from a mound a little higher than the dorsal floor of the telson and between the 2nd and 3rd spine. Dorsal floor of telson major declivity immediately posterior to the mound, followed by a slow decline to the base of the cercopod. Cercopods somewhat longer than dorsum of the telson, the basal three-quarters hardly thinning to a small naked spine, then a rapid thinning to an acute apex. About 12–13 long setae (about 2.5 times diameter of cercopod) on basal 75% of cercopod; these setae two segmented. Distal 25% with a cirrus of small denticles.

Hermaphrodite. Head ( Fig 6 D) with ocular tubercle prominent, with compound eye occupying most (ca 80%) of it. Rostrum a smooth bulge at an angle of about 160o to the frons and with a small ocellus, less than 25% the size of eye. Dorsal organ posterior to eye by about its height, pedunculate and asymmetrical and 75% the height to ocular tubercle.

First antennae a little longer than peduncle of the second antennae, with about eight lobes each with many short sensory hairs.

Second antennae as in male.

Carapace ( Fig 6 B) as in male, though dorsum more vaulted.

Thoracopods. Eighteen of typical Eulimnadia structure.

Trunk dorsum with 3–9 setae terminally, these setae few, short and stout on last few segments, numerous and longer on segments 8–15 and hardly any setae on anterior trunk segments 1–7.

Telson ( Fig 6 G) as in male, though with 1 or 2 cercopod setae and telsonic spines fewer. The space between the 3rd and 4th spine is shorter in hermaphrodites.

Variability. As in most Eulimnadia , many meristic structures are variable numerically, with the full variation not known as only 6 specimens examined all from the one site. Other possible sites where the same egg structure was found were not examined due to extreme syntopy (up to four molecular species present ( Schwentner et al., 2015)). Even so in the population from the pond on Bloodwood Station telsonic spines varied from 10–14, and cercopod setae from 10–13. Of the only two males in the collection, one had its rostrum truncated (by attempted carnivory?) so variability in male rostra is unknown, but the female rostra were of uniform structure. Similar eggs were found at many other sites in the central Paroo catchment but were not specifically related to adults because of extreme syntopy in most of these (see Schwentner et al., 2015).

Comments. This species is distinctive by the lateral spines on the palps of the claspers. Other species such as E. dahli , E.centerania sp. nov., E. pinochionus sp. nov. and E.taroomaensis sp. nov. have 10–15 long cercopod setae, but whereas they have many (>13) telsonic spines, E. beverleyae sp. nov. has only about 12 telsonic spines with a marked gap between the 3rd and 4th and with the caudal filaments arising from between the 2nd and 3rd spine. This species shares the dorsal spines on the clasper finger with E. feriensis (Timms, 2015) . Among Australian Eulimnadia , the eggs are distinctive with their ca 30 groove/ridge systems and lack of any protrusions.

Few males occur in the collections, probably indicating the androdioecious mode of reproduction and the apparent females being putative hermaphrodites (Weeks et al., 2008), but there is no histological proof of this.

Eulimandia beverleyae sp. nov. could be any one of four of Schwentner et al ’s (2015) species G,H, K or 0, such was the high syntopy in many Paroo sites.

Distribution and ecology. Judging from eggs examined across the eastern inland, E. beverleyae sp. nov. is common in the central Paroo in a variety of habitats (clear grassy pools, Blackbox swamps, creek pools, and even in claypans). Similar eggs have been found at Moonie, via Goondiwindi in inner southwest Queensland.

Figures

FIGURE 3. Eulimnadia eggs. A, E. dahli Sars, (Phillips Gorge, WA); B, E. dahli Sars, (Charlotte Waters, NT); C, E. australiensis sp. nov. (Moonbi. NSW); D, E. australicemsis sp. nov. (Nudgee, Qld); E, near E. australiensis sp. nov?, (Bloodwood, NSW); F. E. beverleyae sp. nov. (Bloodwood, NSW), G, E. canalis, sp. nov. (Bloodwood, NSW). H, E. centenaria (Kings Tableland, NT) sp. nov., I, enlargement of part of egg of E. centenaria sp. nov. Scale bars 0.5 mm, except for I for which the bar = 0.01 mm.

FIGURE 6. Eulimnadia beverleyae sp. nov. Bloodwood, NSW. A, male carapace; B, female carapace; C, male head and antennae; D, female head; E, male telson; F, male clapser; G, female telson. Scale bars 1 mm.