On a new genus and species of Hemicytheridae (Ostracoda, Crustacea) from the southern Brazilian coast
Author
de Morais, Anderson L. M.
Universidade Federal do Rio Grande do Sul, Departamento de Paleontologia e Estratigrafia, Caixa Postal 15001, 91501 - 970, Porto Alegre, RS, Brazil.
crescermorais@hotmail.com
Author
Coimbra, João C.
Universidade Federal do Rio Grande do Sul, Departamento de Paleontologia e Estratigrafia, Caixa Postal 15001, 91501 - 970, Porto Alegre, RS, Brazil.
joao.coimbra@ufrgs.br
text
Iheringia
2014
Série Zoologia
2014-09-30
104
3
367
372
http://dx.doi.org/10.5281/zenodo.7802489
journal article
10.1590/1678-476620141043367372
0073-4721
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.
Tab. I. Occurrence of
Auricythere sublitoralis
gen. nov., sp. nov.
in the study area.
| Sample |
Municipality |
Beach |
Coordinates |
Substrate |
N° carapaces |
N° valves |
| M0901N |
Florianópolis |
Armação |
27°43’S/48°30’W |
Algae |
0 |
2 |
| M0904N |
Florianópolis |
Armação |
27°43’S/48°30’W |
Algae |
0 |
2 |
| M0905N |
Florianópolis |
Ponta das Canas |
27°23’S/48°26’W |
Sediments |
0 |
2 |
| M0910N |
Florianópolis |
Naufragados |
27°50’S/48°33’W |
Algae |
1 |
6 |
| M0955N |
Barra Velha |
Grant |
26°41’S/48°40’W |
Algae |
1 |
0 |
| M0941N |
Porto Belo |
Estaleiro |
27°07’S/48°31’W |
Algae |
0 |
3 |
| M0942N |
Porto Belo |
Estaleiro |
27°07’S/48°31’W |
Algae |
10 |
6 |
| M0943N |
Porto Belo |
Estaleiro |
27°07’S/48º31’W |
Algae |
12 |
14 |
| M0946N |
Bombinhas |
Tainha |
27°12’S/48°30’W |
Algae |
0 |
1 |
| M0947N |
Bombinhas |
Tainha |
27°12’S/48°30’W |
Algae |
4 |
0 |
| M0960N |
Bombinhas |
Sepultura |
27°08’S/48°28’W |
Algae |
6 |
1 |
| M0961N |
Bombinhas |
Sepultura |
27°08’S/48°28’W |
Algae |
11 |
11 |
| M0962N |
Bombinhas |
Sepultura |
27°08’S/48°28’W |
Sediments |
1 |
1 |
| M0949N |
Bombinhas |
Sepultura |
27°08’S/48°28’W |
Algae |
2 |
0 |
| Total |
48 |
49 |
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)
.