OSTRACOD RESEARCH

at the Lake Biwa Museum, Japan


Robin James Smith

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Genus Cryptocandona Kaufmann, 1900

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

Two species have been reported from Japan:

1. Cryptocandona brehmi (Klie, 1934)


Right side view of a female Cryptocandona brehmi, length 0.85mm.



External view of a female left valve of Cryptocandona brehmi, length 883 microns.


Additional figures in: Namiotko, & Danielopol 2002 (carapace and appendages), Smith 2011 (carapace and antennule), Chang et al. 2012 (carapace).
Habitat: A cave (Klie 1934), and a spring-fed pond (Smith 2011).
Mode of life: Benthic.
Reproductive mode: Asexual. Males unknown.
Known distribution: Shiga Prefecture (Smith 2011) and Nagano Prefecture (Klie 1934), Japan. Elsewhere, known from South 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.

Namiotko, T. and Danielopol, D. L. 2002. Morphology and phylogenetic affinities of Cryptocandona brehmi (Klie, 1934) (Ostracoda, Podocopida). Crustaceana, 74, 1349-1363.

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.


2. Cryptocandona tsukagoshii Smith 2011


External view of a female left valve of Cryptocandona tsukagoshii, length 708 microns.


Additional figures in: Smith 2011 (carapace and appendages), Chang et al. 2012 (carapace).
Habitat: River gravels (Smith 2011) and springs (Chang et al. 2012).
Mode of life: Interstitial.
Reproductive mode: Probably asexual. Males unknown.
Known distribution: Shiga Prefecture, Japan (Smith 2011) and South Korea (Chang et al 2012).


Photograph of the type locality: a tributary of the Yasu River, Tsuchiyama-cho, Koka, Shiga Prefecture, N35º 00’ 18.1", E136º 22’ 26.7", altitude 608 m (29 January 2010).

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. 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 Cryptocandona brehmi Cryptocandona tsukagoshi
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 about as wide as posterior one
Carapace - ornamentation - denticlesNo denticles near ventral margin
Carapace - ornamentation - sulcusNo sulcus
Carapace - ornamentation - surfaceSurface smooth
Carapace - width/length ratio (w/l)Less than 0.4 (slender species)
Antennule - segmentsSeven moveable segments
Antennule - Rome organNo Rome organ
Antenna - exopoditeExopodite reduced to small segment
Antenna - swimming setaeNo swimming setae present
Fifth limb - morphologyMaxilliped
Sixth limb - segmentsFive segments
Sixth limb - setae on first segmentOne seta
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 - segmentsFive segmentsFour segments*
Seventh Limb - first segmentThree setae
Caudal ramusElongate ramus with two claws and two setae
Caudal ramus - attachmentWith no loops

* The seventh limb has a partially divided third segment.