CONCHOECIINI Chavtur & Angel, 2011

Chavtur, Vladimir G. & Angel, Martin V., 2011, Revision of Metaconchoecia (Ostracoda: Halocyprididae) and the designation of two new tribes Conchoeciini and Metaconchoeciini 2857, Zootaxa 2857 (1), pp. 1-87 : 7-8

TRIBE CONCHOECIINI Chavtur & Angel new status

Type genus. Conchoecia Dana 1849

Composition and main characters. The new tribe consists of 20 genera ( Alacia Poulsen, 1973 ; Boroecia Poulsen, 1973 ; Conchoecetta Claus, 1890 ; Conchoecia Dana, 1849 ; Conchoecilla Claus, 1890 ; Conchoecissa Claus, 1890 ; Discoconchoecia Martens, 1979 ; Gaussicia Poulsen, 1973 ; Loricoecia Poulsen, 1973 ; Macroconchoecia Granata and Caporiacco, 1949 ; Mikroconchoecia Claus, 1890 ; Mollicia Poulsen, 1973 ; Obtusoecia Martens, 1979 ; Orthoc- onchoecia Granata and Caporiacco, 1949; Paraconchoecia Claus, 1890 ; Paramollicia Poulsen, 1973 ; Platyconchoecia Poulsen, 1973 ; Porroecia Martens, 1979 ; Proceroecia Kock, 1992 ; Pseudoconchoecia Claus, 1890 ).

All these genera have the LAG opening on the dorsal margin of the left carapace valve posterior to mid-length and usually close to the posterior dorsal corner. The position of the opening of the RAG opens is more variable. In most genera it opens on the margin of the right carapace valve close to the posterior ventral corner. In some of the genera the opening is further forward on the ventral margin; the most extreme example is in Conchoecilla , in which the gland opens just below the rostral incisure. In other genera the gland opening is displaced dorsally up the posterior margin, but never above mid-height (e.g. some species of Paraconchoecia ). The genera in this tribe are quite disparate in many of their carapace characters such as size, shape, shoulder vaulting and ornamentation and armature. The PDC is often more angled or even armed with spines on one or both of the carapace valves. The rostra are more elaborate and can be asymmetrical. The external surfaces of the carapace valves vary from being totally smooth to be sculpted shallowly or deeply incised concentric, rectilinear, oblique or polygonal patterns. Other groups of glands may be present along the margins of the carapace valves. In summary:

1. They cover almost the full adult size ranges of halocyprid ostracods from 0.6 to 6.5 mm.

2. The carapace ornamentation ranges from being totally smooth to having faint or deeply incised patterns of longitudinal or concentric lines, or polygonal cells. In a few species armatures of spines line the carapace margins and/or the ridges of the sculpturing, or, in juveniles of one species, the margins of the shoulder vaults.

3. The shoulder vaults can be accentuated, or angled or even winged (e.g. in Alacia )

4. The posterior dorsal corner can be rounded or sharply angled and may be armed with one or more spines on one or both valves.

5. In female the second segment of the first antenna often carries a dorsal seta which is probably homologous to the seta that in males locks around the stem of the frontal organ.

6. The labrum is generally flat or smoothly notched, and is flanked by a double row of numerous, long and curved filaments.

7. The first segment of the endopodite of the maxilla generally has six anterior setae, one lateral seta, and three posterior setae.

8. The toothed edge of the mandibular basale has two peg teeth, which may be spinose or bare. The first of the six triangular cutting teeth is slightly offset from the other five. The inner tooth is broad, and often overlaps more than two of the cutting teeth.

9. The female frontal organ can have a clearly differentiated capitulum in those species that do not have the basal segments of the first antenna fused.

10. In males the c-seta of the first antenna is relatively long (>10% carapace length). The a-seta is often S–shaped and inflated at its base, and is simple in all genera except in Mikroconchoecia , in which it is bifid.

11. The hook appendages on the endopodite of each male second antennae are dimorphic, the most extreme example of this dimorphism is seen in Obtusoecia , in which the right hook is very large, whereas the left ‘hook’ is reduced to a short straight peg.