Three new species of non-marine ostracods (Crustacea, Ostracoda) from small water bodies of northern China

Abstract

Three new species, Pseudocandona chenisp. nov., Cyclocypris pangisp. nov., and Tonnacypris rectangularissp. nov., collected from northern China, are described in this study. Pseudocandona cheni, of the compressa group, is difficult to be distinguished from other members of the same group by carapace morphology alone, but can be readily recognised by the structure of the hemipenis comprised of a long lobe a, distally inflated lobe h, and exteriorly pointed lobe b, as well as thick trunks of the male fifth limb endopodites. Cyclocypris pangi, despite its similarity in carapace morphology to its congeners, can be identified based on the morphology of the hemipenis, which bears a slender, slightly curved lobe h, and an S-shaped process accompanying lobe b, in addition to the rectangular trunk of the male fifth limb endopodite. On the other hand, Tonnacypris rectangularis, described on the basis of females only, can be distinguished from other Tonnacypris Diebel & Pietrzeniuk, 1975 representatives by its distinct sub-rectangular carapace alone. Other differences include the length of the swimming setae, the length of the distal claws on the second antennae, and the morphology of the pincer organ on the seventh limb. This study contributes to the poorly known extant non-marine ostracod fauna of Inner Mongolia and Beijing, and generally to the central-eastern Palaearctic region. In addition, the known distribution range of Tonnacypris is extended eastwardly by T. rectangularis. The valve-morphology data are useful for identifying fossil/sub-fossil representatives.

Allometry in Late Devonian Podocopa ostracods (Crustacea) and its implications for ostracod ontogeny

“…The soft parts of Recent ostracods are totally enclosed by the carapace. Generally, the anterior part contains the head capsule, antennules, antennae, mandibles and maxillule, while various organs such as the thoracopods, the reproductive parts and the digestive system develop in the middle and the posterior parts (Yu 2014). Therefore, the overlapping of valves of C. honggulelengensis may be good to protect the soft parts, and the elongate carapace during the stages A‐2 and A‐1 may be a response to inner organ expansion (e.g.…”

“…2004) have rays and setae that protrude from the pores. The soft setae may have sensory functions, enabling them to detect changes in the surrounding environment (Yu 2014), and they may also help to retain a drop of water around the carapace when they crawl out of the water in a shallow‐water environment. The length and roughness of the setae may aid movement by presenting a larger surface area to push against the water, enabling the organism to move faster and further (Horne et al .…”