A review of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) species from eastern Australia with the description of three new species

Australia is predicted to have a high number of currently undescribed ostracod taxa. The genus Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) occurs in Australia and New Zealand, and has recently shown potential for high speciosity, after the description of nine new species from Western Australia. Here, we focus on Bennelongia from eastern Australia, with the objectives of exploring likely habitats for undiscovered species, genetically characterising published morphological species and scanning classical species for cryptic diversity. Two traditional (morphological) species are confi rmed to be valid using molecular evidence (B. harpago De Deckker & McKenzie, 1981 and B. pinpi De Deckker, 1981), while three new species are described using both morphological and molecular evidence. Two of the new species belong to the B. barangaroo lineage (B. dedeckkeri sp. nov. and B. mckenziei sp. nov.), while the third is a member of the B. nimala lineage (B. regina sp. nov.). Another species was found to be genetically distinct, but is not formally described here owing to a lack of distinguishing morphological features from the existing species B. cuensis Martens et al., 2012. Trends in diversity and radiation of the genus are discussed, as well as implications these results have for the conservation of temporary pool microfauna and our understanding of Bennelongia’s evolutionary origin

Evolution, systematics & geographic parthenogenesis of Ilyodromus (Crustacea, Ostracoda)

Most multicellular organisms reproduce sexually at some point in their life cycle. This is paradoxical because being asexual is theoretically far more advantageous. Asexual organisms do not need to find and court new mates, they reproduce at a faster rate, and with no males, all members of the population contribute toward population growth rate. With over 20, often mutually exclusive hypotheses, this paradox resists a synthesised explanation, and continues to represent one of the largest gaps in our understanding of fundamental evolutionary theory. Clearly, more real world studies are required that document the selective mechanisms underlying differences in evolutionary fitness between sexual and asexual organisms. Some species can use either sexual or asexual reproduction, and remarkably, populations that use sexual reproduction can have distinctly different geographic distributions from those that use asexual reproduction. This phenomenon, whereby different distributions of reproductive mode can be observed within the same or closely related species, is called geographic parthenogenesis. These patterns hold promise in providing real world evidence for mechanisms leading to differences in evolutionary fitness between sexual and asexual lineages, because the two regions that sexual and asexual lineages occupy can be characterised by environmental tolerance ranges that in turn may be associated with selection pressure. This thesis addresses the lacking real world evidence for selective mechanisms behind differences in fitness between sexual and asexual organisms, by seeking to develop and use a model system from which the importance of environmental parameters in explaining reproductive mode can be quantified. A freshwater crustacean (Ilyodromus, Ostracoda) occurring in rock outcrop pools along an ecological gradient in south western Australia was investigated. This crustacean employs both reproductive modes to varying degrees, such that the proportion of males in a population is indicative of the extent to which sexual reproduction is used. Unfortunately, since the systematics of this genus were poorly understood, one could not be sure of whether variation in reproductive mode observed between populations could also be due to lineage divergence, and an extensive systematic revision was also necessary for the development of thismodel system. The key findings of this thesis are: 1. An improved understanding of the systematics of Ilyodromus, specifically: a) Revised characters that are considered typical of the genus. b) The boundaries between Ilyodromus and other similar genera. c) Detailed species descriptions for ten nominal species, and three as yet unnamed species. d) An improved ability to identify female-only populations 2. The model system constructed and used in this thesis enables the importance of environmental parameters in explaining reproductive mode to be quantified 3. Parthenogenesis tends to occur more in less stable (or more arid) habitats, while sexual reproduction tends to occur more in more stable (higher rainfall) habitats. 4. This, alongside patterns of species distribution, suggests that variation in reproductive mode is closely linked with processes of speciation and adaptive response to emptied niches.https://ro.ecu.edu.au/theses_ebooks/1000/thumbnail.jp

Cypridocopina Jones 1901

Suborder Cypridocopina Jones, 1901 <p> <b>Superfamily Cypridoidea Baird, 1845 Family Cyprididae Baird, 1845</b></p> <p> <b>Subfamily Herpetocypridinae Kaufmann, 1900 Tribe Herpetocypridini Kaufmann, 1900</b></p>Published as part of <i>Shearn, Rylan, Halse, Stuart, Koenders, Annette, Schön, Isa & Martens, Koen, 2014, Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia, pp. 101-145 in Zootaxa 3878 (2)</i> on page 103, DOI: 10.11646/zootaxa.3878.2.1, <a href="http://zenodo.org/record/227457">http://zenodo.org/record/227457</a&gt

Ilyodromus obtusus Sars 1894, n. sp.

<i>Ilyodromus obtusus</i> Sars, 1894 <p>(Figs 11–13)</p> <p> v*1894 <i>Ilyodromus</i> obtusus n. sp. <b>—</b> Sars: 46–48, pl. 6 figs 4a–d.</p>Published as part of <i>Shearn, Rylan, Halse, Stuart, Koenders, Annette, Schön, Isa & Martens, Koen, 2014, Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia, pp. 101-145 in Zootaxa 3878 (2)</i> on page 122, DOI: 10.11646/zootaxa.3878.2.1, <a href="http://zenodo.org/record/227457">http://zenodo.org/record/227457</a&gt

Ilyodromus smaragdinus Sars 1894, n. sp.

<i>Ilyodromus smaragdinus</i> Sars, 1894 <p>(Figs 8–10)</p> <p> v*1894 <i>Ilyodromus smaragdinus</i> n. sp. —Sars: 43–45, pl. 6, figs 2a–c.</p>Published as part of <i>Shearn, Rylan, Halse, Stuart, Koenders, Annette, Schön, Isa & Martens, Koen, 2014, Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia, pp. 101-145 in Zootaxa 3878 (2)</i> on page 116, DOI: 10.11646/zootaxa.3878.2.1, <a href="http://zenodo.org/record/227457">http://zenodo.org/record/227457</a&gt

Ilyodromus substriatus Sars 1894, n. sp.

<i>Ilyodromus substriatus</i> Sars, 1894 <p>(Figs 14–16)</p> <p> v*1894 <i>Ilyodromus substriatus</i> n. sp. <b>—</b> Sars: 45–46, pl. 6 figs 3a–c.</p>Published as part of <i>Shearn, Rylan, Halse, Stuart, Koenders, Annette, Schön, Isa & Martens, Koen, 2014, Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia, pp. 101-145 in Zootaxa 3878 (2)</i> on page 127, DOI: 10.11646/zootaxa.3878.2.1, <a href="http://zenodo.org/record/227457">http://zenodo.org/record/227457</a&gt

Ilyodromus varrovillius King 1855, n. sp.

<i>Ilyodromus varrovillius</i> (King, 1855) <p>(Figs 5–7)</p> <p> *1855 <i>Cypris varrovillia</i> n. sp. <b>—</b> King: 66, pl. 10 fig d.</p> <p> <i>nov. comb.</i> v1894 <i>Ilyodromus varrovillius</i> (King) —Sars: 41–43, pl. 6 figs 1a–c.</p>Published as part of <i>Shearn, Rylan, Halse, Stuart, Koenders, Annette, Schön, Isa & Martens, Koen, 2014, Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia, pp. 101-145 in Zootaxa 3878 (2)</i> on page 110, DOI: 10.11646/zootaxa.3878.2.1, <a href="http://zenodo.org/record/227457">http://zenodo.org/record/227457</a&gt

Redescriptions of six species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda, Cyprididae) from New Zealand and Eastern Australia

In this paper, we redescribe six species of the genus Ilyodromus Sars, 1894: I, stanleyanus (King, 1855), I. varrovillius (King, 1855), I. smaragdinus Sars, 1894, I. obtusus Sars, 1894, I. substriatus Sars, 1894 and I. viridulus (Brady, 1886) using materials stored in the Oslo museum (Norway) and (re-) described by G.O. Sars. For each species examined, we have identified a number of additional diagnostic characters to those used by Sars and earlier authors. In particular, the length of setae, claws and segments of the antennule, antenna, sixth limb, and caudal ramus appear to be important for species delineation in the genus, as does the internal structure of the valves

Bennelongia pinpi De Deckker 1981

<i>Bennelongia pinpi</i> De Deckker, 1981 <p>Figs 9-10</p> Remarks <p> <i>Bennelongia pinpi</i> De Deckker, 1981 was described from Pine Tree Creek Lagoon, north of Hughenden in Queensland, Australia. The species was characterized by its strongly pronounced beak-like expansion of the LV and the outline of the hemipenes (De Deckker 1981). At the time of the description these characters were unique and enabled a simple diagnosis of the species. Since then, two more species from within the same lineage have been described (Martens <i>et al.</i> 2012) that are closely related to <i>B. pinpi</i> with respect to the absence of anteroventral lapel on the RV, the formation of a bulbous expansion in that place, and the hemipenis outline. Furthermore, some characters were found to be variable within <i>B. pinpi</i> upon examination of non-type populations, making the diagnosis of <i>B. pinpi</i> from its lineage sister taxa less obvious than is indicated in its description. Illustrations showing the variability within this species were needed to help elucidate the diagnostic characters that can be used for their identification. Thus, detailed drawings of the hemipenes and prehensile palps from non-type localities are provided, which alongside the <i>B. pinpi</i> description (De Deckker 1981) show the expected variability within the species and the characters that allow their diagnosis from the more recently described <i>B. strellyensis</i> Martens <i>et al.</i>, 2012 and <i>B. kimberleyensis</i> Martens <i>et al.</i>, 2012.</p> <p> <b>Diagnosis</b> (modified after De Deckker 1981)</p> <p>Cp with pronounced anterior rostrum but bluntly pointed posterior; sub-triangular in right lateral view, circular in dorsal/ventral view (more so in females), LV overlapping RV on all sides, external valve surface smooth to pseudopunctate with sparsely distributed setae restricted to ventral and anteroventral region. LV with pronounced anteroventral beak-like expansion often extending below plane of horizontal ventral margin. RV with anteroventral flange or lapel absent, but with bulbous expansion of outer list in its place; anterior selvage with flange-like expansion and additional inner submarginal list. Rpp with proximal segment approximately two times as long as central width, distal palp segment short and triangular with rounded distal margin and apical sensory organ. Lpp with first segment over three times as long as central width; second palp segment sickle-shaped, short, and variably rounded, sometimes by over 180 degrees. Hemipenis with ls protruding well beyond ms, more so than any other described species in this lineage; ms forming a three dimensional structure, embracing ls on three sides, dorsal lobe with rounded distal margin.</p> <p> <b>Measurements</b> (in µm)</p> <p> Ƌ: RV: L = 1998-2095 (<i>n</i> =3), H = 1175-1218 (<i>n</i> =3). LV: L = 2208-2223 (<i>n</i> =3), H = 1293-1320 (<i>n</i> =3). Cp: L = 2063-2232 (<i>n</i> =9), W = 1285-1523 (<i>n</i> =3), H = 1258-1368 (<i>n</i> =3).</p> <p> ♀: RV: L = 2080-2103 (<i>n</i> =3), H = 1233-1273 (<i>n</i> =2). LV: L = 2200-2280 (<i>n</i> =2), H = 1288-1335 (<i>n</i> =2). Cp: L = 2055-2300 (<i>n</i> =7), W = 1195-1265 (<i>n</i> =5), H = 1218-1300 (<i>n</i> =2).</p> Localities investigated <p> <i>Salt Lake</i>, freshwater lake north of Hughenden on Kennedy Developmental Highway QLD, collected on 9 Jun. 2011 by RS and AK, coordinates: 19º51’19.9” S - 144º16’11.3” E (Sample QLDP11A).</p> <p> <i>Pelican Lake</i>, north of Hughenden on Kennedy Developmental Highway QLD, collected on 9 Jun. 2011 by RS and AK, coordinates: 19º51’53.1” S - 144º15’20” E (Sample QLDP13A).</p> <p> <i>Lake Louisa</i>, north of Hughenden on Kennedy Developmental Highway QLD, collected on 9 Jun. 2011 by RS and AK, coordinates: 19º53’45.6” S - 144º15’55.5” E (Sample QLDP12A).</p> Material investigated or illustrated <p>ƋƋ from Pelican Lake (W40043), Salt Lake (W40027) and Lake Louisa (W40035), with soft parts dissected in sealed slide, valves stored dry in a micropalaeontological slide. Three Ƌ carapaces from Pelican Lake (W40045-W40047), Salt Lake (W40029-W40031) and Lake Louisa (W40037-W40039) stored in a micropalaeontological slide.</p> <p>♀♀ from Pelican Lake (W40044), Salt Lake (W40028) and Lake Louisa (W40036) with soft parts dissected in sealed slide, valves stored dry in a micropalaeontological slide. Three ♀ carapaces from Pelican Lake (W40048-W40050), Salt Lake (W40032-W40034) and Lake Louisa (W40040-W40042) stored in a micropalaeontological slide.</p> <p> Several <i>in toto</i> specimens in EtOH from Pelican Lake (W40080).</p> Differential diagnosis <p> <i>Bennelongia pinpi</i> can be diagnosed as within the <i>B. pinpi</i> lineage due to its large carapace, well developed anterior rostrum, blunt posterior, the bulbous expansion of the valve in place of the absent anteroventral lapel of the RV, the well-developed anteroventral beak-like expansion of the LV and the well sclerotized hemipenes with a three dimensional ms enveloping the ls.</p> <p> It can be distinguished from the other species in this lineage by the elongated first Lpp segment (shorter in <i>B. strellyensis</i> Martens <i>et al.</i>, 2012 and <i>B. kimberleyensis</i> Martens <i>et al.</i>, 2012), the rounded dorsal margin of the Rpp second segment (triangular-pointed in <i>B. kimberleyensis</i> Martens <i>et al.</i>, 2012), the narrow ls of the hemipenis (broader in <i>B. strellyensis</i> Martens <i>et al.</i>, 2012 and <i>B. kimberleyensis</i> Martens <i>et al.</i>, 2012) and the extension of the ls far beyond the ms (much less extended in <i>B. strellyensis</i> Martens <i>et al.</i>, 2012 and <i>B. kimberleyensis</i> Martens <i>et al.</i>, 2012).</p> <p> <b>Additional description</b> (modified after De Deckker 1981)</p> <p>Cp (Fig. 9 E-H) with pronounced anterior rostrum but bluntly pointed posterior; sub-triangular in right lateral view (Fig. 9 K-L), circular in dorsal/ventral view (more so in females), LV overlapping RV on all sides, external valve surface smooth to pseudopunctate with sparsely distributed setae restricted to ventral and anteroventral region.</p> <p>LV (Fig. 9A, C) with pronounced anteroventral beak-like expansion, often extending below plane of horizontal ventral margin, dorsal margin highest at valve mid-point.</p> <p>RV (Fig. 9B, D) in lateral view with dorsal margin highest at valve mid-point; anteroventral flange or lapel absent, but with bulbous expansion of outer list in its place (Fig. 9 I-J); anterior selvage with flangelike expansion, and additional inner submarginal list.</p> <p>Most appendages as typical of the genus and without special features.</p> <p>Rpp (Fig. 10D) with first segment approximately two times as long as central width, subapically with two slender sensory organs, one long and one short often overlapping; second palp segment short and triangular with rounded distal margin and apical sensory organ.</p> <p>Lpp (Fig. 10C, D) with first segment over three times as long as central width, subapically with one sensory organ; apically with rounded outgrowth; second palp segment sickle-shaped, short, and variably rounded (Fig. 10C versus Fig. 10E), sometimes by over 180 degrees with distal sensory organ.</p> <p>Hemipenes (Fig. 10 A-B) with width of ls variable depending on slide preparation (Fig. 10a vs Fig. 10B), ls protruding well beyond ms, more so than any other described species in this lineage; ms consisting of three lobes, distal part of ms produced into a three-dimensional lobe embracing the ls on proximal and distal sides, a small additional dorsal lobe with rounded distal margin, and a proximal lobe nearly straight and incomplete.</p> Ecology and distribution <p> The distribution of <i>B. pinpi</i> appears to be isolated to an area north of Hughenden. At the time of its description, the species had been found in Pine Tree Creek Lagoon, Agnes Lake, Salt Lake and Louisa Lake (De Deckker 1981). It appears that most of these populations still exist. Here, an additional locality (Pelican Lake) is recorded.</p>Published as part of <i>Shearn, Rylan, Koenders, Annette, Halse, Stuart & Martens, Isa Schön and Koen, 2012, A review of Bennelongia De Deckker & McKenzie, 1981 (Crustacea, Ostracoda) species from eastern Australia with the description of three new species, pp. 1-35 in European Journal of Taxonomy 25</i> on pages 20-24, DOI: 10.5852/ejt.2012.25, <a href="http://zenodo.org/record/3858390">http://zenodo.org/record/3858390</a&gt