OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Undulacandona Smith, 2011

Superfamily: Cypridoidea Baird, 1845
Family: Candonidae Kaufmann, 1900
Subfamily: Candoninae Kaufmann, 1900

Two species have been reported from Japan:

1. Undulacandona colymba Smith, 2011


Left side view of a female Undulacandona colymba, length about 0.8 mm.


External view of a male left valve of Undulacandona colymba, length 778 microns.


External view of a male right valve of Undulacandona colymba, length 795 microns.


The male sexual organ of Undulacandona colymba, length 306 microns. (Photograph is inverted to allow for easy comparison with species below.)

Additional figures in: Smith & Kamiya 2015 (carapace and appendages).
Habitat: Groundwater (well).
Mode of life: Subterranean.
Reproduction mode: Sexual.
Known distribution: Currently only known from a well in Nagahama City, Shiga Prefecture (Smith & Kamiya 2015).

References:
Smith, R. J. & Kamiya, T. 2015. Four new species of the subfamily Candoninae (Crustacea, Ostracoda) from freshwater habitats in Japan. European Journal of Taxonomy, 136, 1-34.

2. Undulacandona spinula Smith, 2011

Show synonymy list

2011 Undulacandona spinula n. sp. - Smith: 28-33, 35, figs 9A-E, 10 & 11, Table 1.
2012 Undulacandona spinula Smith, 2011 - Karanovic & Lee: Appendix 1.
2015 Undulacandona spinula Smith, 2011 - Smith & Kamiya: 30-31.

Status: full synonymy list

Hide synonymy list


Left side view of a male (top) and a female Undulacandona spinula, length about 0.8 mm.


External view of a male left valve of Undulacandona spinula, length 770 microns.


External view of a male right valve of Undulacandona spinula, length 765 microns.


The male sexual organ of Undulacandona spinula, length 253 microns.

Additional figures in: Smith 2011 (carapace and appendages).
Habitat: Groundwater (well).
Mode of life: Subterranean.
Reproduction mode: Sexual.
Known distribution: Currently only known from a well in Otsu City, Shiga Prefecture (Smith 2011).

References:
Karanovic, I. & Lee, W. 2012. A review of candonid ostracods (Crustacea: Ostracoda: Podocopida) from East Asia, with descriptions of five new species from South Korea. Zootaxa, 3368, 7-49.

Smith, R. J. 2011. Groundwater, spring and interstitial Ostracoda (Crustacea) from Shiga Prefecture, Japan, including descriptions of three new species and one new genus. Zootaxa, 3140, 15-37.


Key characters Undulacandona spinula & Undulacandona colymba
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 not visible
Carapace - lateral view - ventral marginVentral margin approximately straight to concave
Carapace - lateral view - valve heightLeft and right valves similar height
Carapace - internal viewAnterior calcified inner lamella wider than posterior one
Carapace - ornamentation - denticlesNo denticles near ventral margin
Carapace - ornamentation - sulcusNo sulcus
Carapace - ornamentation - surfaceSurface striated
Carapace - width/length ratio (w/l)Less than 0.4 (slender species)
Antennule - segmentsFive moveable segments
Antennule - Rome organNo Rome organ
Antenna - exopoditeExopodite reduced to small segment
Antenna - swimming setaeNo swimming setae present
Fifth limb - morphologyMaxilliped; Male palps one fused mass
Sixth limb - segmentsFive segments
Sixth limb - setae on first segmentNo setae
Sixth limb - h3 seta on final segmentH3 seta short; much shorter than half length of claw
Seventh Limb Cleaning limb, with three setae at end
Seventh Limb - segmentsFour segments
Seventh Limb - first segmentThree setae
Caudal ramusElongate ramus with two claws and two setae
Caudal ramus - attachmentWith no loops