Mehmet Yavuzatmaca

Elevational distribution and species diversity of freshwater Ostracoda (Crustacea) in Çankırı region (Turkey)

We investigated how the richness and ecological characteristics of non-marine ostracod species varied across nine 100-m elevation bands (from 549 to 1457 m) in the Çankırı region. We collected a total of 37 taxa (25 living and 12 sub-recent) from 114 of 130 aquatic sites sampled during September of 2011; 34 of the taxa were new records for the region. Eight widely distributed ‘cosmopolitan’ species (Candona neglecta, Cypridopsis vidua, Heterocypris incongruens, Ilyocypris bradyi, Limnocythere inopinata, Potamocypris villosa, Prionocypris zenkeri, and Psychrodromus olivaceus) were found more frequently than other species. The first two axes of canonical correspondence analyses (CCA) explained 73.2% of the correlation between 11 species and 5 environmental variables. Of which, electrical conductivity (F = 3.99, p = 0.028) and altitude (F = 2.69, p = 0.004) were the most explanatory (p < 0.05) variables for species. Optimum altitude and water temperature values of the cosmopolitan species were relatively higher than the other species. Significant regression models (p < 0.01, r2 = 0.81) indicate that the frequency of occurrence was affected by changes in numbers of samplings sites from 549 to 1457 m. When highest numbers of species (15 spp.) were found at the range of 1231–1332 m, numbers of asexual species (10 spp.) were twice of the sexual species (5 spp.) with no statistical difference between numbers of swimming (7 spp.) and non-swimming (8 spp.) species. Results were discussed based on the ecological conditions that individual species prefer.

Gomphocythere besni n. sp. (Crustacea, Ostracoda) from a man-made pool (Adıyaman, Turkey)

We describe a new species (Gomphocythere besni n. sp.) from the Tavaş man-made pool in Besni town (Adıyaman, Turkey). The species has several differences from its congeners in furcal structures (forked organ, seta of caudal ramus), numbers of setae on maxillula and maxillular palp, particular ornamentation with up to eight fossae in each mesh of the reticulation and in the presence of two types of lateral pore-canals (single pore opening with a sensillum and sieve plates) on the carapace. The finding of the new species extends the known geographical distribution of the living forms of the genus further to the North. The new species was found from relatively cool (16.6 ºC) and medium oxygenated waters (7.36 mg/L) in a mixture of sand and gravel substrate. Details about its ecology and taxonomic status are also compared and discussed with other species of the same genus.

On Schornikovdona gen. nov. (Ostracoda, Candonidae) from rheocrene springs in Texas (U.S.A.)

A new candonid genus, Schornikovdona gen. nov., with its type species Schornikovdona bellensis sp. nov., is described from rheocrene springs of Bell County, Texas. It is designated to the tribe Candonini due to the smooth carapace surface, normal pore openings with sensory seta, the presence of a 5-segmented first antenna, two long sexual bristles on the second antenna in males, the narrowly fused terminal segment of the Md palp, a long penultimate segment of the Mxl palp, two long and one short setae on the terminal segment of T3, the absence of an “e” seta on T3, the presence of a posterior seta on the uropod, the presence of 5 + 2 rows of spines on Zenker’s organ, and other characteristics found in the tribe. The main diagnostic characteristics separating the new genus from the other genera in the tribe are the shape of the carapace, the reduced numbers of segments in the first antenna, reduction or absence of exopodial setae in the second antenna, asymmetrical clasping organs, the uropod with one rod-shaped claw, the different shape of the hemipenis, and differences in parts of the chaetotaxy. Based on these differences, we propose Schornikovdona gen. nov. as a new genus, with the new species S. bellensis sp. nov., in the subfamily Candoninae in the family Candonidae.