Auricythere, de Morais & Coimbra, 2014

de Morais, Anderson L. M. & Coimbra, João C., 2014, On a new genus and species of Hemicytheridae (Ostracoda, Crustacea) from the southern Brazilian coast, Iheringia, Série Zoologia (Série Zoologia) 104 (3), pp. 367-372 : 368-369

Auricythere gen. nov.

Type species: Auricythere sublitoralis sp. nov., by monotypy.

Diagnosis. Carapace small, somewhat ear-shaped mainly in LV lateral view. LV conspicuously larger than RV; overlap pronounced in dorsal region and immediately above the caudal process. Surface ornamented by costae and reticulae. Ribs predominantly low, thick and somewhat truncated. Ocular tubercle well developed, crossed by a strong rib. Ventro-lateral rib not superimposed on the corresponding margin. Posterior region with vertical rib bifurcated at the top and the bottom. Accommodation groove well developed. Hinge holamphidont; LV posterior socket with a conspicuous aurila-tooth and an auxiliary anti-slip tooth at its posterior end (sensu JELLINEK, 1995). Central muscle scars with three frontal and four adductors (1+2+1+1). The frontal ones sometimes not well defined; upper and middle scars frequently somewhat anastomosed. Large duplicature with anterior vestibule. Radial porecanals numerous, simple and straight. Sexual dimorphism not prominent; females a bit higher and longer.

Etimology. From Latin origin, auris = outline similar a human ear.

Remarks. According to BENSON (1961), the hemicytherid ostracodes invariably have one or two of the four adductor scars subdivided. However, HAZEL (1967) claims that Hemicytherinae is the only subfamily of Hemicytheridae with one or more subdivided adductor scars.

Regarding to the frontal muscle scars, Hemicytherinae can be subdivided into two groups with two or three scars ( BENSON, 1961; MORKHOVEN, 1963; HAZEL, 1967). JELLINEK (1995, tab. 2) presents a comparative table of the genera grouped into the Tribe Aurilini , highlighting that this would be the only tribe to include genera of Hemicytherinae with two frontal scars.

HAZEL (1967) proposes that Hemicytherinae should be subdivided into three major groups: Orionina -group, Aurila -group and Muelerina -group. However, HARTMANN & PURI (1974) erects, among others, the tribes Orioninini, Aurilini and Urocythereidini, and includes, in each of them, the same genera proposed by HAZEL (1967), respectively, with minor changes. In turn, YAJIMA (1982) follows the proposal of HAZEL (1967) and inserts a fourth group (monogeneric) in Hemicytherinae, Finmarchinella Swain, 1963 . Diagnostic features compared among the different tribes of Hemicytherinae, confronted to those of the new genus, indicate that Auricythere gen. nov. is best allocated in Aurilini . For more details of the diagnostic characters of this tribe see JELLINEK (1995).

Auricythere gen. nov. occurs in the study area along with species of two other aurilinid genera: Auradilus costatus (Hu, 1979) and Aurila ornellase Coimbra & Bergue, 2003 . Auradilus Jellinek, 1995 differs from Auricythere gen. nov. by well-defined diagnostic features, such as the pattern of the adductor muscle scars [1(2)+2-2- 1] and the characteristic postero-dorsal shoulder. In turn, the highly diverse and cosmopolitan genus Aurila Pokorný, 1955 is more ear-shaped in LV lateral view and possesses a quite distinct ornamentation constituted by punctae and/ or reticulae, often concentric about mid-point; never with heavy ribs. For more details of morphological features of all Aurilini genera see JELLINEK (1995, tab. 2), and only for a review of the diagnosis of Aurila see HARRISON et al. (2000).