Eulimnadia dahli Sars 1896

Brian V Timms, 2016, A partial revision of the Australian Eulimnadia Packard, 1874 (Branchiopoda: Spinicaudata: Limnadiidae), Zootaxa 4066 (4), pp. 351-389: 353-357

publication ID

http://doi.org/10.11646/zootaxa.4066.4.1

publication LSID

lsid:zoobank.org:pub:B0F56A57-C033-48C6-BB66-B007A93FC259

persistent identifier

http://treatment.plazi.org/id/038C2831-6522-A12C-94B3-FEF1E571ADD4

treatment provided by

Plazi

scientific name

Eulimnadia dahli Sars 1896
status

 

Eulimnadia dahli Sars 1896  .

(Figs. 1,2,3A,B)

Eulimnadia dahli Sars, 1896: 14  –30, pl. 2–6; Sayce, 1903: 244 (text), 247–248 (synopsis), pl. 34, fig. 1,a–c; Wolf, 1911: 254 (list), 270 (Text); Dakin, 1914: 295 (list); Henry, 1924: 122 (list); Daday, 1926: 4 (key), 16–20, figs. 128–129; Richter & Timms, 2005: 348.

Limnadia dahli Brtek, 1997: 57  (list).

Type locality. Mt Showbridge, near Darwin, Northern Territory, collector K. Dahl and date 3 November 1894.

Type material. Series of specimens noted as syntypes in the Oslo Museum. These specimens were not consulted, as the diagrams and description by Sars are excellent, though with SEM technology the egg can be described in more detail.

Material studied. Northern Territory. 27 females, Delamere Highway, 113 km S of junction with Victoria Highway, 16 o 11 ’S, 131 o 59 ’E, M.J. Tyler, SAMAbout SAM C 8450; 52 specimens, Charlotte Waters, pre 1912, unknown collector, NMVAbout NMV J 53350. Queensland. 4 females, Walkamin Research Station near Atherton, fish rearing pond 6, 22 Oct 1997, B. Herbert AM P 97799. Western Australia. Stonewall Ck, via Kununurra, 2 Feb 1978, Coll JEB, SAMAbout SAM C 8453; 7 males, Kimberleys, Phillips Gorge, 28.7 km from Barnett River Crossing, 3 Feb 1986, M.J. Tyler, SAMAbout SAM C 8454; numerous females, Kimberleys, Phillips Gorge, 28.7 km from Barnett River Crossing, 3 Feb 1986, M.J. Tyler, SAMAbout SAM C 8455 1 male, 12 females, Kimberleys, Phillips Gorge, 28.7 km from R Crossing, 3 Feb 1986, M.J. Tyler, SAMAbout SAM C 8456; 36 females, Kimberleys, 87 km N of Halls Ck on Northern Highway, 6 Feb 1982, M.J. Tyler & M. Davies, SAMAbout SAM C 8457.

Diagnosis. Egg spherical averaging 22 polygons, often as uneven pentagons or hexagons, with central groove and either lacking any frills on the polygon boundaries, or with minor frill. Adults with twenty trunk segments (all other Australian Eulimnadia  have 18), numerous (mean 18) long (2.5 x or more cercopod diameter) cercopod setae, about 17 telsonic spines, and 8–9 antennomeres. Also the male typically has a distinctly triangular rostrum.

Short description. Male and Hermaphrodite (Figs.1,2). This species is described in detail by Sars (1896). In essence (from original description plus present observations), the male has a triangular rostrum, first antenna with about eight lobes, and second antenna with eight antennomeres on each ramus; carapace with four growth lines; 20 trunk segments; both claspers have a two segmented long palp with ca. five spines at the palpomere junction, and a telson with ca. 15 dorsal spines, the cercopod with about 18 long setae. The hermaphrodite is similar, but with a short rounded rostrum, and a similar telson as the male. The egg has about 24 polygons each with a central depression and unadorned edges.

Egg ( Fig 3View FIGURE 3). Spherical with about 22 polygons each an uneven pentagon or hexagon with a central groove and even slopes to a sharp marginal ridge. Polygon boundaries with a minor frill or none at all, and often with a spiniform protrusion at ridge junctions.

Comments. I have seen 8 collections containing this species (Figs.1,2). In all except two (Phillips Gorge, SAMAbout SAM C 8456; Charlotte Waters, NMVAbout NMV 14427) individuals have 20 trunk segments, thus distinguishing species from all other Australian Eulimnadia  . It is possible these exceptions may consist of juveniles. The egg is its other most distinguishing feature. Typically these have ca 22 polygons (range 20–28) often distinctly hexagonal (though sometimes pentagonal) and an overall size of 196 Μm (range 162–212 Μm). The edge of the polygons may be smooth (old eggs?) or with a minor frill extending a little to a short spiniform protrusion at edge junctions ( Fig 4View FIGURE 4 A,B). Interestingly, Sars 1896 noted the hexagonal facets and his figure is remarkably accurate.

Other distinguishing features of lesser value include the male rostrum which is distinctly triangular and symmetrical. The telson has about 17 telsonic spines (range 14–18), and about 18 cercopod setae (range 16–23). Generally the setae are long (2.5 to 3 x cercopod diameter and almost reaching the posterior apex of the telson). The clasper often has a small rounded bulge mediodistally just basal to the apical knob and typically 5 (range 3–6) spines at the palp segmental junction. The number of antennal lobes varies from 8–12 in males and 5–8 in females and 8–9 antennomeres on the rami of the second antenna. In many populations the numbers of spines and setae on each antennomere do not vary much from proximal to distal antennomeres and the ventral setae are unusually long (3– 5 x diameter of antennomeres) ( Fig 1View FIGURE 1 C). Some specimens have a supernumerary spine anterior to the first large telsonic spine (as in SAMAbout SAM C 8455 Phillips Gorge population, Fig. 1View FIGURE 1 G; interestingly Sars’ illustration shows one such spine too. Finally the moveable finger rarely has 3 spines dorsally, a condition occasionally seen in other species (e.g. E. gnammaphila  sp. nov., see below) and when numerous and always present, sometimes an identifying feature (eg. E. feriensis  , see Timms 2015).

FIGURE 2. Eulimnadia dahli Sars, 1896  . Charlotte Waters, NT. A, female head; B, female telson, C, male 2 nd clasper; all Charlotte Waters NMVAbout NMV 14427; D, female head; E, female telson; both Atherton, AM P 97799; F, female telson, Stonewall Ck, SAMAbout SAM C 8453; G, female telson, Halls Ck. SAMAbout SAM C 8457.

Further south, in a band across the continent, there is a species clearly allied to E. dahli  , but they generally have more polygons in the egg and fewer cercopod setae. There were insufficient specimens, or they were too variable for meaningful study.

Weeks et al. 2006 reported E. dahli  from four sites in WA and one in SA, but these are most probably misidentifications ( Table 1). In material I collected from his Pygery Rocks site, SA (AM P 97824) all specimens have 18 trunk segments, ca 10 telsonic spines, <18 cercopod setae and eggs with numerous (> 50) polygons each with central depressions and with frilled polygon boundaries ( Fig 9View FIGURE 9 B,C,D) suggesting E. gnammaphila  sp.nov. (see later) and certainly not E. dahli  . I have also seen their Green Rock material and it has similar characters to that from Pygery Rock. Their material from Bunjil Rocks, The Humps and Kadji Kadji is lost, and the sites need to be recollected to determine their identity. Reed et al (2015), in a molecular analysis of various world Eulimnadia  , note that what they identify as E. dahli  and E. feriensis  are synonymous ( Table 1); again I believe this is because they were dealing with E. gnammaphila  sp. nov. rather than E. dahli  or E. feriensis  .

Timms (2006) lists E. dahli  as a gnammaphile in SA and WA, but this identification was based on eggs which look like those described by Sars (1896), but when their other characters are now taken into account, they are more likely E. gnammaphila  sp. nov.

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. Distribution. Eulimnadia dahli  occurs in northern Australia, including the Kimberleys, Darwin area, Nicholson River in NW Qld (based only on eggs) and Atherton Tableland in NE Qld.

TABLE 1. Alternative identifications for some Australian Eulimnadia.

Initial identification Sites referred too Present identification Reference
E. dahli  Various gnammas in sw WA (see Table 1 in Weeks et al., 2006) E. gnammaphila  sp. nov. Weeks et al., 2006
E. feriensis  Various gnammas in sw WA (see Table 1 in Weeks et al., 2006) E. gnammaphila  sp. nov. Weeks et al., 2006
E. dahli  & E. feriensis  As above, but shown to be synonymous E. gnammaphila  sp. nov. Reed et al., 2015
E. dahli  Widespread in gnammas in sw WA E. gnammaphila  sp. nov. Timms, 2006
Eulimnadia  sp E Near Lake Dunn, Qld E. contraria  sp. nov. Schwentner et al., 2015
Eulimnadia  sp M Near Taroom, Qld E. taroomaensis  sp. nov. Schwentner et al., 2015
Eulimnadia  sp G or H or K or O Various sites in Paroo, NSW E. hansoni  sp. nov. Schwentner et al., 2015

TABLE 1. Alternative identifications for some Australian Eulimnadia.

Initial identification Sites referred too Present identification Reference
E. dahli  Various gnammas in sw WA (see Table 1 in Weeks et al., 2006) E. gnammaphila  sp. nov. Weeks et al., 2006
E. feriensis  Various gnammas in sw WA (see Table 1 in Weeks et al., 2006) E. gnammaphila  sp. nov. Weeks et al., 2006
E. dahli  & E. feriensis  As above, but shown to be synonymous E. gnammaphila  sp. nov. Reed et al., 2015
E. dahli  Widespread in gnammas in sw WA E. gnammaphila  sp. nov. Timms, 2006
Eulimnadia  sp E Near Lake Dunn, Qld E. contraria  sp. nov. Schwentner et al., 2015
Eulimnadia  sp M Near Taroom, Qld E. taroomaensis  sp. nov. Schwentner et al., 2015
Eulimnadia  sp G or H or K or O Various sites in Paroo, NSW E. hansoni  sp. nov. Schwentner et al., 2015
SAM

South African Museum

NMV

Museum Victoria

Kingdom

Animalia

Phylum

Arthropoda

Class

Branchiopoda

Order

Diplostraca

Family

Limnadiidae

Genus

Eulimnadia

Loc

Eulimnadia dahli Sars 1896

Brian V Timms 2016

2016
Loc

Eulimnadia dahli

Richter 2005: 348
Daday 1926: 4
Henry 1924: 122
Dakin 1914: 295
Wolf 1911: 254
Sayce 1903: 244Sars 1896: 14

1903
Loc

Limnadia dahli

Brtek 1997: 57