Two new Cypridopsinae Kaufmann, 1900 (Crustacea, Ostracoda) from southern Africa

Two new Cypridopsinae ostracods, Potamocypris meissnerisp. nov. and Sarscypridopsis harundinetisp. nov. are described. Both were found only as asexual (all-female) populations in temporary waters of southern Africa. Potamocypris meissneri was collected from a small pan in the North-West Province of South Africa. It is approximately 0.5 mm long and belongs to the species group with long swimming setae on the second antennae. However, the species has a somewhat isolated position in the genus owing to the conspicuously reticulated carapace, which is furthermore densely covered by prominent conuli with normal pores carrying long sensilla, as well as to the wide anterior and posterior flanges on the left valve. To allow identification of the new species in relation to its closest congeners, a key to the species of the genus Potamocypris Brady, 1870 from southern Africa is provided. The genus Sarscypridopsis McKenzie, 1977 mostly has an Afrotropical distribution with only few species occurring in other regions. Sarscypridopsis harundineti was collected from floodplains of the outskirts of the Okavango Delta in Botswana. It is approximately 0.4 mm long and can be distinguished from congeners mainly by the smaller and more oval-shaped valves. We conclude that southern African Cypridopsinae urgently need integrated taxonomic revision, by means of both morphological characters and DNA-sequence data.

Ecomorphology of Ostrea edulis (Linnaeus, 1758) in Kuala Gigieng Waters, Aceh Besar District

Ostrea edulis is one of the most common types of meat oysters and is commonly consumed by people in Kuala Gigieng, but until now there is not much scientific information about this species. The purpose of this study was to describe the ecomorphology of Ostrea edulis in Kuala Gigieng waters. This research was conducted from August to September 2013 in Kuala Gigieng Waters, Aceh Besar District. The method used in this research is purposive sampling. Identification of samples based on shell morphological characteristics including the exterior and interior of the shell using a magnifier lamp. The results showed that Ostrea edulis found in Kuala Gigieng waters had round, rough, hard, thick and uneven shells. The two valves are also not the same size, where the left valve is more concave than the right valve which tends to be flat. This is a form of the adaptation pattern of Ostrea edulis in Kuala Gigieng which tends to have a medium sand and clay sand substrate with a fairly high predation from both natural and human predation.

Convergent and Parallel Evolutionary Traits in Early Cretaceous Rudist Bivalves (Hippuritidina)

Early Cretaceous Hippuritida clades, requieniide (family Requieniidae) and hippuritide (families Radiolitidae, Polyconitidae,Caprinidae, “Caprinulidae” and Caprinuloideidae), show distinctive myophoral arrangements and shell structures. Nevertheless they share some characters, such as the transverse shell thickening of the myophores of the attached valve which are convergent traits in Lovetchenia (Requieniidae) and Homopleura (Monopleuridae). The bent posterior myophore of the right valve of Pseudotoucasia (Requieniidae) closely resemble the posterior myophore of the left valve of Horiopleura and Polyconites (Polyconitidae). The shell cellular structure is one of the key attributes of the family Radiolitidae (e.g.Eoradiolites) but this structure is also present in some advanced Requieniidae (“Toucasia-Apricardia “group). Canaliculate shell structures are convergent evolutionary traits which are common in the Caprinidae and Caprinuloideidae and also exist in the Polyconitidae and “Caprinulidae”. In most of the foregoing canaliculated groups, two trends are well expressed, reflecting parallel evolution: expansion of canals into the entire shell and increasing complexity of canal architecture. Convergent taxa took some advantages by using former innovations. An Albian peak of convergence coincided with the emergence of new clades, which suggests a reset following the mid-Aptian extinction event.

Ecology of the Early Jurassic bivalve Harpax spinosus (J. SOWERBY, 1819)

The plicatulid bivalve Harpax spinosus is a common element of Pliensbachian to Lower Toarcian benthic community relicts occurring preferredly in fine- grained siliciclastic and mixed carbonate-siliciclastic sediments. There is general agreement that the bivalve was a secondary soft substrate dweller, being cemented with its flat to slightly concave right valve to small shells and bioclasts during early stages of growth and turning into a free recliner during later growth stages. Disagreement exists with respect to the life orientation of the bivalve, whether as free recliner it rested with its convex left valve or with its slightly concave right valve on the substrate. The former growth position would have required the bivalve to flip over when turning into a free recliner. Moreover, most authors assume that the bivalve discarded its host substrate during its reclining stage. The analysis of approximately 1500 specimens from the Upper Pliensbachian Amaltheenton Formation of southern Germany and time-equivalent horizons of southern France and Portugal shows that the bivalve remained cemented to the host substrate throughout its life time, even when the latter no longer supported the shell. The bivalve most likely rested with its concave valve on the soft substrate. The radially protruding spines served to keep the commissure above the sediment-water interface, to stabilize the shell and to prevent the shell from sinking into the sediment (snow-shoe strategy). Differences in the size of individuals at the localities investigated are thought to reflect differences in the degree of environmental stress, most likely caused by fluctuations in the oxygen content of the bottom water masses or by increasing soupiness of the substrate.

Campanian and Maastrichtian hippuritid rudists (Hippuritida, Bivalvia) of the Chiapas Central Depression (southern Mexico) and implications for American multiple-fold hippuritid taxonomy

Hippuritids, particularly those with multiple-folds, are one of the most characteristic components in uppermost Cretaceous rudist-bearing strata of the Caribbean Province. The hippuritid rudist fauna of the Chiapas Central Depression includes the following taxa:Vaccinites vermuntiMac Gillavry, 1937 andBarrettiacf.B. ruseaeChubb, 1967 from the early Campanian Suchiapa Formation;B. moniliferaWoodward, 1862,B. gigasChubb, 1955, andParastroma trechmanniChubb, 1967 from the mid Campanian Suchiapa Formation; andPraebarrettia sparcilirata(Whitfield, 1897) from the early Maastrichtian Ocozocoautla Formation. These six species are described herein in detail. New observations on the outer shell layer structure of the right valve and the pore-canal system of the left valve led to amending the diagnoses of the g|eneraBarrettiaWoodward, 1862,ParastromaDouvillé, 1926, andPraebarrettiaTrechmann, 1924. Also, the revision of Chiapas’ and other American species of multiple-fold hippuritids led to proposed changes in their generic adscription.

Two new species of Cypretta Vávra, 1895 (Crustacea, Ostracoda) from Thailand and discussion of genus

Two Cypretta species from Thailand are described: Cypretta aculeata n. sp. and Cypretta triangulata n. sp. Cypretta aculeata n. sp. can be characterized chiefly by the valve surface equipped with long setae, spine-like bristle and distinctive pits, the presence of tubercles on postero-ventral margin of the internal left valve and the denticulated ridge on the postero-ventral part of the internal right valve, the long d1 seta on the second thoracopod (T2), and the long Sp seta on the caudal ramus (CR). Based on the valve surface ornamentation, C. aculeata n. sp. is similar to C. globosa (Brady, 1886), C. intonsa Furtos, 1936, C. spinosa Cohuo-Durán et al., 2013 and C. vivacis Würdig & Pinto 1993. A key to the species within this group is thus provided. The main diagnostic features of Cypretta triangulata n. sp. are the triangular carapace in the dorsal view, the absence of tubercles on the postero-ventral margin of the internal left valve, the presence of denticulated ridge on the postero-ventral part of the internal right valve, the short d1 seta on T2 and the long Sp seta on the CR. The diagnostic characters for the species identification of the genus Cypretta are briefly discussed with regard to the morphology and number of the septa and lunules, the traits of the internal side of the valves, the features of soft body parts (such as the mandible, the thoracopods and the CR) and the morphological aspects of the hemipenis.

New genus of subfamily Cypridopsinae Kaufmann, 1933 (Crustacea: Ostracoda) from Thailand

The new genus Thaicypridopsis gen. nov. described here belongs to the tribe Zonocypridini Higuti & Martens, 2012 in the subfamily Cypridopsinae Kaufmann, 1900. It is the first record of the Recent representatives within this tribe in Southeast Asia and Oriental regions. Thaicypridopsis gen. nov. has a number of remarkable characters that distinguish it from other genera in the subfamily: a submarginal row of distinctive tubercles on the postero-ventral part of the right valve in the interior view, a strong serrated claw G2 on the second antenna with an apical concavity, large bristles with hirsute endings and spatula-shaped apexes on all three maxillular endites and a bifurcate tip on the terminal claw of the second thoracopod. One new species, Thaicypridopsis longispinosa sp. nov., is described under this new genus in the present contribution. Apart from the above diagnostic characters, the new species also has long spines on the valve surface as its outstanding feature. The new taxon is morphologically compared with other related species and genera within and outside the subfamily Cypridopsinae. In addition, due to the new genus belonging to a group of genera with the left valve overlapping the right valve in the subfamily, a key to the genera within this group is given.

Siamopsis gen. nov. and five new species of the subfamily Cypridopsinae Kaufmann, 1900 (Crustacea: Ostracoda) from Thailand

Siamopsis gen. nov., described here, belongs to a group of genera with the right valve overlapping the left valve in the subfamily Cypridopsinae Kaufmann, 1900 of the family Cyprididae Baird, 1845. The distinguishing characters of the new genus are in the morphology of its valves and soft parts. The postero-dorsal margin of the internal left valve is plate-like protruded. The morphology of this plate varies in different species, e.g., some species bear a tooth-like tubercle on the plate. The posterior margin of the right valve is recurved inwardly at ca mid-height, resulting in the occurrence of a lobe-like expansion that can clearly be seen in the dorsal and caudal views of the carapace. In addition, the other diagnostic soft part features of the new genus are the cylindrical caudal ramus, the presence of two t-setae on the female A2 penultimate segment, the very elongated terminal segment of the Mx1 palp, the morphology of the two large bristles (tooth bristles) of the Mx1 third endite (one smooth, one serrated) and the absence of d-seta on T1. In the present paper, five new species are described under this new genus: Siamopsis renateae gen. et sp. nov., S. suttajiti gen. et sp. nov., S. conspecta gen. et sp. nov., S. khoratensis gen. et sp. nov. and Siamopsis planitia gen. et sp. nov. A key to the species of Siamopsis gen. nov. is also provided.

A new species of Cavernocypris Hartmann, 1964 (Crustacea: Ostracoda) from caves in South Korea

Surveys of caves in South Korea yielded a new species of the ostracod genus Cavernocypris Hartmann, 1964, herein described as Cavernocypris danielopoli Smith & Kamiya n. sp. This is the fifth described species in this widely distributed genus, and can be discriminated from its congeners by the highly triangular shape of the carapace in lateral view, caused by a large dorsal protrusion on the left valve. A second triangular-shaped morphotype was also collected, differing from the first by a lower carapace and less pronounced dorsal protrusion. As it is not clear at present if this represents a separate species or intraspecific variation, it is left in open nomenclature. The lack of a pigmented eye, a highly triangular carapace and no carapace pigmentation suggests that Cavernocypris danielopoli Smith & Kamiya n. sp. is the most adapted species in the genus to a stygobiotic lifestyle. Another Korean species, Cavernocypris coreana (McKenzie, 1972), found in caves and spring discharges, has a reduced number of antennule segments, common for stygobiotic species, but this feature is lacking in the new species. This suggests that within the genus, species have followed different evolutionary pathways to adapt to the subterranean realm.