Leite et al.—Limnic Ostracoda from the Lower Cretaceous of Brazil In the Potiguar Basin: H. alta, H. crepata and P. martinsi,
all from the middle–upper Aptian (Do Carmo et al., 2013). In the Jatobá Basin: H. angulata (upper Aptian) (Tomé et al., 2014). In the Sergipe-Alagoas Basin: H. angulata (upper Aptian) (Krömmelbein and Weber, 1971); C. jequiensis (Barremian) (Krömmelbein and Weber, 1971; Poropat and Colin, 2012a; Antonietto, 2015). In the Recôncavo Basin: C. conjugata (Barremian)
(Krömmelbein and Weber, 1971; Poropat and Colin, 2012a); C. hystrix (Berriasian to Valanginian) (Krömmelbein, 1962; Poropat and Colin, 2012a); C. infima (Berriasian) (Krömmelbein and Weber, 1971; Poropat and Colin, 2012a). In the Cedro Basin: H. angulata (upper Aptian) (Tomé,
2007). In the Paraná Basin: B. fulfaroi (Upper Cretaceous) (Dias-Brito et al., 2001). In the Tucano Basin: B. ovum (Berriasian) (Krömmelbein, 1965b; Poropat and Colin, 2012b). In Argentina, Pozo D-129 Formation in Cerro Chenques:
N.(Protoneuquenocypris) antiqua, Aptian (Musacchio and Simeoni, 1991) and Barremian-Aptian (Carignano et al., 2017). In the Austral Basin: N.(Protoneuquenocypris) antiqua (lower to upper Albian) (Ballent et al., 2011). In Africa, Gabon Basin and Congo and Cabinda Basin: H.
symmetrica (Barremian) (Grosdidier et al., 1996; Bate, 1999). Additionally, the Zone Harbinia spp. 201–218, coded as
NRT-011 (Do Carmo et al., 2008) was defined from the Araripe Basin, and comprises the Alagoas Floor (Schaller, 1968; Moura, 1987), upper Aptian–lower Albian (Antonietto et al., 2012), where the genus Harbinia plays an important role in dating Brazilian basins, both continental and marginal (Antonietto et al., 2012). The Paracypridea brasiliensis Zone, coded as NRT-O04, was defined from the Recôncavo Basin, where the occurrence of Cypridea hystrix is well marked in the Paracypridea bicallosa (NRT-O04.3) and Paracypridea maacki (NRT-O04.4) subzones (Viana et al., 1971; Cunha and Moura, 1979; Regali and Viana, 1989), of Valanginian age (Caixeta et al., 1994). The Tereza Farm outcrop has 11 species, which is the most
diversified. Ostracode assemblages occur with up to eight species at the richest levels, and when this abundance lessens, ostracode assemblages occurwith up to four species per level. The São José creek outcrop has seven species, where ostracode assemblages occurwith up to four species at the richest levels, and with up to two species at most levels. Additionally, the abundance of specimens is less,when compared to Tereza Farm. TheQuiricó creek outcrop has four species, all of them in one single level. Only B. ovum and P. pintoi n. sp. occur at the Tereza Farm
and São José and Quiricó creeks. At the São José creek outcrop there is a predominance of Harbinia species, which occur in assemblage with B. ovum and P. pintoi n. sp. only at the middle portion of the sequence. At the Quiricó creek outcrop, B. ovum and P. pintoi n. sp. occur in assemblage with A. longiformis n. sp. and B. fulfaroi. At the Tereza Farm outcrop, C. hystrix occurrance deter-
mines a chronostratigraphic attribution ofValanginian age for the basal portion of the sequence. The species that are in assemblage with C. hystrix, and therefore are of Valanginian age, are: P. martinsi,C. conjugata,C. jequiensis,N.(Protoneuquenocypris) antiqua,and T. sanfranciscanensis n. sp. The middle portion of the sequence is of Hauterivian age, possibly up to Aptian age. The species that are either at the basal portion and the middle portion,
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and of Valanginian–Aptian age are: P. pintoi n. sp., A. longiformis n. sp., B. fulfaroi, B. ovum,and C. infima. At São José creek, the occurrences of Harbinia indicate a
chronostratigraphic attribution of Aptian age for the top of the basal portion and the middle and upper portions. Therefore, B. ovum and P. pintoi n. sp. occur from Valanginian to Aptian. At Quiricó creek, there is the level of papyraceous shale
where the fish fossil Dastilbe moraesi occurs, along with leaf
impressions.Associated with this level, according to Lima (1979) and Arai et al. (1995), there is the Transitoripollis crisopolensis Palynozone, coded as P-230, indicating a Barremian age. The ostracode assemblage of P. pintoi n. sp., A. longiformis n. sp., B. ovum,and B. fulfaroi occurs below the papyraceous shale level, attributed possibly to the Valanginian–Barremian interval.
Conclusions
This study analyzed 168 samples from three outcrops encom- passing the São Francisco Basin, in the State of Minas Gerais, southeastern Brazil. Sixteen species were identified, of which five are unprecedented for theQuiricó Formation, and consequently for the Cretaceous of the São Francisco Basin. There is also the iden- tification of the genus Timiriasevia, unprecedented in the paleon- tological record of Brazil, as well as the description of three new species: Penthesilenula pintoi n. sp., Alicenula longiformis n. sp., and Timiriasevia sanfranciscanensis n. sp. Additionally, con- sidering the recovery of well-preserved material, new descriptions and emended diagnoses are proposed for four species: Brasacypris ovum, Cypridea conjugata, Cypridea hystrix,and Cypridea infima. The genus Alicenula is given a new diagnosis, due to the biblio- graphic confirmation of the presence of internal teeth on the left valve, which is a characteristic not present in the original diagnosis. The species Brasacypris fulfaroi, Penthesilenula martinsi,
Cypridea conjugata, Cypridea jequiensis, and Neuquenocypris (Protoneuquenocypris) antiqua represent herein their oldest record. The stratigraphic distribution is: B. fulfaroi, Valanginian to Upper Cretaceous; P. martinsi, Valanginian to Albian; C. conjugata, Valanginian to Barremian; C. jequiensis, Valangi- nian to Barremian-Aptian; N.(Protoneuquenocypris) antiqua, Valanginian to Albian. The species Brasacypris ovum presents the most recent record, with stratigraphic distribution from Berriasian to Aptian. Timiriasevia sanfranciscanensis n. sp., due to its occurrence exclusively at the Tereza Farm, is only attributed to the Valanginian. Penthesilenula pintoi n. sp. has a stratigraphic distribution from Valanginian to Aptian, and Alicenula longiformis n. sp. ranges from Valanginian to possibly Barremian. Harbinia species, recovered only at the São José creek outcrop, are of Aptian age. Therefore, the Quiricó Formation becomes attributed to the Valanginian–Aptian interval. The new data on ostracode taxonomy presented herein
improve the current understanding of distribution of limnic ostracodes from the Cretaceous of Brazil, Argentina, and Africa because it is possible to develop a correlation study with 13 other basins: Grajaú, Araripe, Potiguar, Jatobá, Sergipe-Ala- goas, Recôncavo, Cedro, Paraná, and Tucano, from Brazil; Gabon, Congo, and Cabinda basins in Africa; and the Austral Basin, in Argentina. From this study, it is possible to infer that the Quiricó Formation began its deposition during the Valanginian.
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