Knoxina sp., 1932

Guillam, Elvis, Forel, Marie-Béatrice, Song, Junjun & Crasquin, Sylvie, 2022, Late Devonian-early Carboniferous ostracods (Crustacea) from South China: taxonomy, diversity and implications, European Journal of Taxonomy 804, pp. 1-62 : 23-24

Knoxina sp.

Fig. 6S–T

Knoxiella subreticulata Wang, 1983 – Song & Gong 2019: fig. 4o.

Material examined

CHINA • 1 complete carapace ( Fig. 6S ); Blue Snake section, Gelaohe Formation, sample 19BAI 74; P6M 3873 • 1 complete carapace ( Fig. 6T ); Blue Snake section, Gelaohe Formation, sample 19BAI 74; P6M 3874 • 7 complete carapaces; Blue Snake section, Gelaohe Formation, samples 19BAI 74, 19BAI 80. All from the Famennian, late Devonian.

Dimensions

RV: L = 536–585 µm, H = 309–343 µm, H/L = 0.57–0.6.

LV: L = 484–558 µm, H = 263–311 µm, H/L = 0.5–0.6.

Remarks

The present species is rare in the studied material and is represented by poorly preserved specimens that do not allow for a specific attribution. It is attributed to the genus Knoxina because it has a sulcus opened dorsally just anterior to mid-L, a node in antero-dorsal part of the carapace and longitudinal ridges, which are diagnostic of the genus. It is morphologically close to Knoxina costata ( Zaspelova, 1959) from the Frasnian of the Russian Platform by its rectangular outline, presence and location of anterior, ventral and dorsal ridges and node located in front of sulcus. However, the specimens found here have a more rounded morphology, a strong overlap all around free margin and are smaller (based on the dimension of the figured holotype of Knoxina costata shown in Zaspelova (1959: pl. 8 fig. 9): L = 700µm, H = 400 µm and H/L around 0.57). The presence of pit and ornamentation cannot be verified because of the poorly preservation of our material. The specimen attributed to Knoxiella subreticulata Wang, 1983 shown in Song & Gong (2019: fig. 4o) does not belong to Knoxiella because it has ridges located dorsally and along ventral margin that point to the genus Knoxina . It is close to Knoxina sp. but the figured carapace is less stocky, has a slightly more concave VB and does not have a strong overlap as our material. The specimen shown in Song & Gong (2019) is a steinkern which would explain these differences so that we still consider it as conspecific.

Occurrence

Samples 19BAI 74, 19BAI 80, Gelaohe Formation, Blue Snake section, Famennian, late Devonian (this work).

Figures

Fig. 6. SEM pictures of ostracods from Blue Snake section, Dushan County, South China, late Famennian–Tournaisian, late Devonian–early Carboniferous. All specimens are temporarily housed in the collections of Sorbonne Université, Paris, France (SU). A. Kloedenellitina sincera Tschigova, 1960, left lateral view of a carapace, sample 19BAI 69 (P6M 3856). B–C. Kloedenellitina spinosa Gurevitch, 1972. B. ♀, right lateral view of a carapace, sample 19BAI 60 (P6M 3857). C. ♂, right lateral view of a carapace, sample 19BAI 69 (P6M 3858). D. Kloedenellitina sygmaeformis Egorov, 1950, right lateral view of a carapace, sample 19BAI 80 (P6M 3859). E. Blessites feluyensis Tschigova, 1977, right lateral view of a carapace, sample 19BAI 39 (P6M 3860). F–I. Hypotetragona angulata (Posner, 1951). F. Adult, left lateral view of a carapace, sample 19BAI 44 (P6M 3861). G. A-1, left lateral view of a carapace, sample 19BAI 02 (P6M 3862). H. A-2, left lateral view of a carapace, sample 19BAI 02 (P6M 3863). I. A-3, left lateral view of a carapace, sample 19BAI 03 (P6M 3864). J–M. Hypotetragona sp. J. Adult, left lateral view of a carapace, sample 19BAI 39 (P6M 3865). K. A-1, left lateral view of a carapace, sample 19BAI 05 (P6M 3866). L. A-2, left lateral view of a carapace, sample 19BAI 60 (P6M 3867). M. A-3, left lateral view of a carapace, sample 19BAI 69 (P6M 3868). N. Knoxiella archedensis Tschigova, 1960, left lateral view of a carapace, sample 19BAI 03 (P6M 3869). O. Knoxiella complanata (Kummerow, 1939), left lateral view of a carapace, sample 19BAI 80 (P6M 3870). P. Knoxiella subcompressa, Wang & Ma, 2007, left lateral view of a carapace, sample 19BAI 68 (P6M 3871). Q–R. Knoxiella cf. subcompressa, Wang & Ma, 2007. Q. Adult, left lateral view of a carapace, sample 19BAI 68 (P6M 3871). R. A-1, left lateral view of a carapace, sample 19BAI 68 (P6M 3872). S–T. Knoxina sp. S. Left lateral view of a carapace, sample 19BAI 80 (P6M 3873). T. Left lateral view of a carapace, sample 19BAI 74 (P6M 3874). U. Knoxites cf. argulata Zaspelova, 1959, adult, left lateral view of a carapace, sample 19BAI 02 (P6M 3875). Scale bars = 100 µm.