OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Vestalenula Rossetti & Martens, 1998

Superfamily: Darwinuloidea Brady & Robertson, 1885
Family: Darwinulidae Brady & Robertson, 1885

Four species have been reported from Japan:

1. Vestalenula cornelia Smith et al. 2006

Figures in: Smith et al. 2006 (carapace and appendages).
Habitat: Runoff of springs.
Mode of life: Benthic.
Reproductive mode: Asexual? (rare males have been found so sexual reproduction cannot be ruled out, Smith et al. 2006).
Known distribution: Kagoshima Prefecture; Ishikawa Prefecture; Ogasawara islands (Smith et al. 2006).

References:
Smith, R. J., Kamiya, T. & Horne, D. J. 2006. Living males of the 'ancient' asexual Darwinulidae (Ostracoda, Crustacea). Proceedings of the Royal Society, B, 273, 1569-1578.

2. Vestalenula cylindrica (Straub, 1952)


Lateral left view of a female Vestalenula cylindrica. Length about 0.47 mm.



Dorsal view of a female Vestalenula cylindrica, anterior to left. Length about 0.47 mm.



External view of a left valve of a female Vestalenula cylindrica. Length 457 microns



External view of a right valve of a female Vestalenula cylindrica. Length 443 microns.


Additional figures in: Smith & Janz 2009 (carapace and appendages).
Habitat: Lake Biwa shoreline, most abundant on willow tree root mats.
Mode of life: Benthic.
Reproductive mode: Asexual (males unknown).
Known distribution: Shiga Prefecture (Smith & Janz 2009). Elsewhere, known from Korea (Chang et al. 2012).

References:
Chang C. Y., Lee, J. & Smith, R. J. 2012. Nonmarine ostracods (Crustacea) from South Korea, including a description of a new species of Tanycypris Triebel (Cyprididae, Cypricercinae). Zootaxa, 3161, 1-19.

Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


3. Vestalenula lundi (Neale & Victor, 1978)


Lateral left view of a female Vestalenula lundi. Length about 0.43 mm.



Dorsal view of a female Vestalenula lundi, anterior to left. Length about 0.43 mm.



External view of a left valve of a female Vestalenula lundi. Length 427 microns



External view of a right valve of a female Vestalenula lundi. Length 405 microns


Additional figures in: Neale & Victor, 1978 (carapace and appendages), Smith & Janz 2009 (carapace).
Habitat: Beaches around Lake Biwa.
Mode of life: Interstitial.
Reproductive mode: Asexual (males unknown).
Known distribution: Shiga Prefecture (Smith & Janz 2009). Elsewhere, known from Sri Lanka (Neale and Victor 1978).

References:
Neale, J. W. & Victor, R. 1978. The Lund University Expedition freshwater Ostracoda from Sri Lanka (Ceylon). Canadian Journal of Zoology 56: 1081-1087.

Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217-241.


4. Vestalenula molopoensis (Martens & Rossetti, 1997)


Lateral left view of a female Vestalenula molopoensis. Length about 0.45 mm.



Dorsal view of a female Vestalenula molopoensis, anterior to left. Length about 0.45 mm.



External view of a left valve of a female Vestalenula molopoensis. Length 451 microns



External view of a right valve of a female Vestalenula molopoensis. Length 437 microns


Additional figures in: Martens & Rossetti 1997 (carapace and appendages), Smith & Janz 2009 (carapace).
Habitat: Beaches around Lake Biwa.
Mode of life: Interstitial.
Reproductive mode: Asexual (males unknown).
Known distribution: Shiga Prefecture (Smith & Janz 2009). Elsewhere, known from South Africa (Martens & Rossetti 1997) and Thailand (Savatenalinton et al. 2008).

References:
Martens, K. and Rossetti, G. 1997. On two new species of Darwinula Brady and Robertson, 1885 (Crustacea, Ostracoda) from South African dolomitic springs. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie 67: 57-66.

Savatenalinton, S., Borgonie, G. and Martens, K. 2008. On Thaicythere srisumonae n. gen., n.sp. (Ostracoda) from Thailand, with notes on the phylogeny of the subfamily Timiriaseviinae Mandelstam, 1960. Crustaceana 81: 411-432.

Smith, R. J. & Janz, H. 2009. Recent ostracods of the superfamilies Cytheroidea and Darwinuloidea (Crustacea) from Lake Biwa, a Japanese ancient lake. Species Diversity, 14, 217 - 241.


Key charactersVestalenula corneliaVestalenula cylindricaVestalenula lundiVestalenula molopoensis
Carapace - ventral valve overlapLeft valve overlaps right along ventral margin
Carapace - margin structure - septaNo septa present
Carapace - margin structure - ridges on inner calcified lamellaNo ridges
Carapace - dorsal view - female with brood pouchBrood pouch visible
Carapace - lateral view - ventral marginVentral margin approximately straight to concave
Carapace - lateral view - valve heightLeft and right valves similar height
Carapace - internal viewNo calcified inner lamella
Carapace - ornamentation - denticlesNo denticles near ventral margin
Carapace - ornamentation - sulcusNo sulcus
Carapace - ornamentation - surfaceSurface smooth
Carapace - width/length ratio (w/l)Between 0.4 and 0.7 (medium species)Less than 0.4 (slender species)Between 0.4 and 0.7 (medium species)
Antennule - segmentsFive moveable segments
Antennule - Rome organRome organ absent
Antenna - exopoditeExopodite reduced to small segment
Antenna - swimming setaeNo swimming setae present
Fifth limb - morphologyWalking leg
Sixth limb - segmentsFive segments
Sixth limb - setae on first segmentThree setae
Sixth limb - h3 seta on final segmentH3 seta short; much shorter than half length of claw
Seventh LimbWalking leg, larger than sixth limb
Seventh Limb - segmentsFive segments
Seventh Limb - first segmentTwo setae
Caudal ramusReduced ramus with one seta
Caudal ramus - attachmentWith no caudal ramus attachment