Bicornucandona, Külköylüoğlu, Okan, Gibson, Randy, Diaz, Peter H. & Colin, Jean-Paul, 2011

Külköylüoğlu, Okan, Gibson, Randy, Diaz, Peter H. & Colin, Jean-Paul, 2011, Bicornucandona gen. nov., sp. nov. (Crustacea, Ostracoda) from Finegan Springs (Texas, U. S. A.), Zootaxa 3059, pp. 47-58 : 50

Genus: Bicornucandona gen. nov.

Type-species: Bicornucandona fineganensis sp. nov. ( Figs 2–6 )

Other species: The genus is presently monospecific.

Etymology. Masculine Latin name ‘bicornu’ meaning ‘two horns’ which represents the two horn-like prolongations on the mid-dorsal margin of the left valve. This prefix is combined with the related genus Candona which lack these structures.

Diagnosis. Two short horn-shaped (M-like) processes on the mid-dorsal area of LV present in both sexes. Area below the horn-like structure distinctly depressed. RV almost trapezoidal in shape with a slightly concave dorsal margin in the middle. Valves strongly asymmetric with left valve overlapping the right along the entire valve margin and especially in the dorsal side where it bears a trapezoidal flat hump bearing two short scaly horns. Both valves have a distinct concave ventral margin. Shape intermediate between the “hoher dreieckiger and trapezartiger (meaning high triangular and trapezoidal) carapaces as defined by Danielopol (1978: 112). Both ends rounded in lateral view, with posterior margin steeper than anterior one in females. In dorsal view, carapace laterally compressed, LV overlaps RV along the entire valve margin. Hinge adont. Central muscle scars typical for the family, gathering in the middle part of the valves. Marginal areas of both valves smooth. Surface of the carapace pitted and covered with conspicuously long and stiff setae with normal pore openings. Calcareous inner lamella broad at both ends. Seta b absent in T1.

Figures

FIGURE 2. SEM photographs of Bicornucandona fineganensis sp. nov. A, B, female: Left and right valves, respectively. C – E, male: C, Dorsal view; D, Ventral view; E, Anterior margin from dorsal view (Scale: 100 µm).

FIGURE 3. SEM photographs of Bicornucandona fineganensis sp. nov. A – F, male. A, Left valve interior view (Note mid-ventral area broken); B, External view of right valve; C, Close view of a single horn from dorsal view along with normal pore openings; D, Left valve external view of horn-like structures dorsally; E, Muscle scars in interior view; F, Two horns on the left valve, dorsal view. (Scale: A, F: 100 µm; B – E: 10 µm).

FIGURE 4. Bicornucandona fineganensis gen. nov., sp. nov. holotype (male L = 0.90 mm): A, A 1; B, A 2; C, Rake-like organ.

FIGURE 5. Bicornucandona fineganensis gen. nov., sp. nov. (A – D, male; E, female). A, Md-palp; B, Max-palp; C, left prehensile palp; D, right prehensile palp; E, T 1 (arrow indicating segmentation). (Scale: A – B: 100 µm; C – D: 10 µm; E: 20 µm).

FIGURE 6. Bicornucandona fineganensis gen. nov., sp. nov. (male). A, T 2; B, T 3; C, Uropod (Fu); D, Zenker organ; E, Hemipenis; (Scale: 25 µm).