Clavofabella? lanshella Guillam & Forel, 2022

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 : 11-12

Clavofabella? lanshella Guillam & Forel sp. nov.

urn:lsid:zoobank.org:act:9B24EB32-22A9-4A92-99D8-6C5F7B6744D0

Fig. 5F–L

Diagnosis

A new species questionably attributed to Clavofabella with elongate outline and laterally compressed spinose free margin at LV.

Etymology

The specific epithet refers to the Latinization of the Chinese ‘ lan she ’, which means ‘blue snake’ in reference to the name given to the section.

Material examined

Holotype

CHINA • 1 complete carapace ( Fig. 5F–G ); Blue Snake section , Gelaohe Formation, sample 19BAI 68; Famennian, late Devonian; P6M 3842 .

Paratype

CHINA • 1 complete carapace ( Fig. 5H ); Blue Snake section , Gelaohe Formation, sample 19BAI 68; Famennian, late Devonian; P6M 3843 .

Other material

CHINA • 1 complete carapace (A-1, Fig. 5I ); Blue Snake section , Gelaohe Formation, sample 19BAI 68; P6M 3844 • 1 complete carapace (A-2, Fig. 5J ); Blue Snake section , Gelaohe Formation, sample 19BAI 68; P6M 3845 • 1 complete carapace (A-3, Fig. 5L ); Blue Snake section , Gelaohe Formation, sample 19BAI 68; P6M 3846 • 20 complete carapaces; Blue Snake section , Gelaohe Formation, samples 19BAI 63, 19BAI 67, 19BAI 68, 19BAI 74. All from the Famennian, late Devonian.

Dimensions

See Fig. 4A .

Description

Carapace large, preplete, ovoid/rectangular (adults) to inverted triangular (young juveniles) in lateral view, lenticular with laterally compressed anterior and posterior margins in dorsal view. Lmax slightly above mid-H, Hmax in front of mid-L, Wmax around mid-H and slightly in front of mid-L. RV overlaps LV all around, with maximum along free margin. Hinge line slightly sinuous with gentle concavity immediately posterior to ACA, slightly invaginated all along its length. Obtuse cardinal angles, ACA about 145°, PCA about 130°. Surface coarsely reticulate with round reticulae. LV with a spinose free margin that could indicate the presence of a velar structure. Pit relatively large (H about 32% of Hmax, L about 14% of Lmax), ovoid, elongated dorso-ventrally, located slightly in front of mid-L, slightly above mid-H, at Wmax.

Remarks

This species is doubtfully attributed to the genus Clavofabella Martinsson, 1955 described from the Late Wenlock (Silurian) of Gotland, Sweden ( Martinsson 1955) because of RV overlapping LV, surface reticulated, sulcal pit and spinose free margin that could indicate the presence of a velar structure and that points to heteromorphs after Moore (1961). However, the tubercles in all known species belonging to Clavofabella are short and rounded and are absent at DB where the dolon is located in heteromorphs. In our material, these structures are spines rather than tubercles and are located along the entire free margin and are larger than those described from all known species belonging to this genus. Clavofabella? lanshella sp. nov. also differs from all other species of this genus by its laterally compressed morphology, more elongate lateral outline, larger sulcal pit, coarse reticulation and straighter DB. The H/L scatter plot of Clavofabella? lanshella sp. nov. ( Fig. 4A ) allows to discriminate four ontogenetic stages (A-3 to Ad). The ontogenetic development of this species is marked by the elongation of the carapace, increasing compression of the free margin, enlargement of the pit and growth of spines along free margin.

Occurrence

Samples 19BAI 63, 19BAI 67, 19BAI 68, 19BAI 74, Gelaohe Formation, Blue Snake section, Famennian, late Devonian (this work).

Figures

Fig. 5. 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 (numbers P6M****).A. Aparchites sp., left lateral view of a carapace, sample 19BAI 08 (P6M 3837). B. Fellerites sp. 1, right lateral view of a carapace, sample 19BAI 67 (P6M 3838). C. Fellerites sp. 2, right lateral view of a carapace, sample 19BAI 80 (P6M 3839). D. Parabolbinella sp., right lateral view of an anteriorly broken carapace, sample 19BAI 74 (P6M 3840). E. Amphissites sp., right lateral view of a steinkern, sample 19BAI 74 (P6M 3841). F–L. Clavofabella? lanshella Guillam & Forel sp. nov. F. Holotype, left lateral view of a carapace, sample 19BAI 68 (P6M 3842). G. Same specimen, dorsal view. H. Paratype, left lateral view of a carapace, sample 19BAI 68 (P6M 3843). I. A-1, left lateral view of a carapace, sample 19BAI 68 (P6M 3844). J. Same specimen, dorsal view. K. A-2, left lateral view of a carapace, sample 19BAI 68 (P6M 3845). L. A-3, left lateral view of a carapace, sample 19BAI 68 (P6M 3846). M–R. Clavofabella? sp. M. Adult, left lateral view of a carapace, sample 19BAI 68 (P6M 3847). N. A-1, left lateral view of a carapace, sample 19BAI 69 (P6M 3848). O. A-2, left lateral view of a carapace, sample 19BAI 68 (P6M 3849). P. A-3, left lateral view of a carapace, sample 19BAI 68 (P6M 3850). Q. A-4, left lateral view of a carapace, sample 19BAI 68 (P6M 3851). R. A-5, left lateral view of a carapace, sample 19BAI 68 (P6M 3852). S. Coryellina grammi Olempska, 1999, left lateral view of a carapace, sample 19BAI 41 (P6M 3853). T. Selebratina sp., left lateral view of a carapace, sample 19BAI 41 (P6M 3854). U. Beyrichiopsis sp., left lateral view of a carapace, sample 19BAI 41 (P6M 3855). Scale bars = 100 µm.

Fig. 4. H/L scatter plots of all specimens belonging to the four new species described in this contribution. A. Clavofabella? lanshella Guillam & Forel sp. nov. B. Sansabella gelaohensis Guillam & Forel sp. nov. C. Sulcella baisuzhena Guillam & Forel sp. nov. D. Cytherellina caerulea Guillam & Forel sp. nov.