Kelanella sp.

Betts, Marissa J., Claybourn, Thomas M., Brock, Glenn A., Jago, James B., Skovsted, Christian B. & Paterson, John R., 2019, Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia, Acta Palaeontologica Polonica 64 (3), pp. 489-522 : 511-512

Kelanella sp.

Fig. 13O.

2017 Kelanella sp. ; Betts et al. 2017b: fig. 14N–U.

Material.— One specimen ( SAM P57235 ) from Clast 5. From the Dailyatia odyssei Zone, WPC, Kangaroo Island , South Australia .

Description. — Single, flattened, spine-like sclerite bearing concentric, fasciculate, growth-related ornamentation (Fig. 13O). Both ends of specimen with open apertures. Smaller aperture is smooth (likely intact) and larger aperture has jagged edges (Fig. 13O 1 –O 3, O 6). Cross section oval with width gently increasing (from about 300–400 μm) towards wider aperture, although in the central zone, the width decreases slightly (Fig. 13O 1). In lateral view, the sclerite profile is gently undulating with a marked change in growth direction coinciding with central zone of decreasing width (Fig. 13O 2). Width of concentric growth increments variable (from about 25–100 μm), with more narrow growth increments in the central zone (Fig. 13O 4) and close to the smaller aperture (Fig. 13O 6). Internally, sclerite bears ornamentation of fine pustules (Fig. 13O 7, O 8).

→ Fig. 13. Problematic, multi-element taxa Stoibostrombus crenulatus Conway Morris and Bengtson in Bengtson et al., 1990 (A–F), Lapworthella fasciculata Conway Morris and Bengtson in Bengtson et al., 1990 (G–N) and Kelanella sp. (O) from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia. A. SAM P 57311 in lateral view. B. SAM P 57312 in lateral view. C. SAM P 57313 in lateral view (C 1); C 2, detail of the aperture showing texture on the internal surface. D. SAM P 57314 in oblique lateral view (D 1); D 2, detail of the characteristic wrinkled external microtexture. E. SAM P 57315 in lateral view. F. SAM P 57316 in lateral view. G. SAM P57317, external ornament. H. SAM P57318. I. SAM P57319. J. SAM P57320. K. SAM P57321. L. SAM P57322. M. SAM P57323. N. SAM P57324. O. SAM P57325, O 3 –O 8, details of the aperture and internal and external ornament.

Remarks. — Kelanella is a tommotiid genus with a more or less global distribution from Cambrian Stage 3 to the Wuliuan ( Devaere et al. 2014b). The sclerites of Kelanella are large by comparison to most other tommotiids and are characterized by multitude of internal septa and a characteristic “gridded” ornament of transverse and longitudinal ribs, often with fine longitudinal striations between ribs Devaere et al. 2014b; Yang et al. 2015). A large number of morphologically variable sclerite morphs are known and these have often been described under different generic names (see review in Devaere et al. 2014b), but the scleritome is still poorly understood ( Devaere et al. 2014b; Yang et al. 2015) and the taxonomic composition of this genus remains uncertain, pending review of larger sclerite assemblages.

In the collections from the WPC, Kelanella is represented by a single long, flattened, spine-shaped sclerite with the characteristic external ornament of fine longitudinal striations (Fig. 13O 1 –O 6). Apart from the broken aperture, the wall of the single sclerite is complete and internal septa could not be observed. However, similar spine-shaped and septate sclerites are often associated with the more characteristic broad sclerites of Kelanella in assemblages from Siberia (with specimens described under the generic name Tesella Missarzhevsky and Grigorieva, 1981 , now considered a junior synonym of Kelanella by Devaere et al. 2014b) Missarzhevsky and Grigorieva 1981: pl. 11: 15), France Devaere et al. 2014b: fig. 9J–L), South China ( Yang et al. 2015: fig. 12F–G), as well as in undescribed collections from Greenland and Siberia (CBS, personal observation 2018). This type of sclerite morphology is not known from other tommotiids.

Betts et al. (2017b) reported Kelanella sp. as a minor component of the fauna of the D. odyssei Zone of the Arrowie Basin. Although no spine-shaped sclerites were illustrated Betts et al. 2017b: fig. 14N–U), such sclerites occur in the associated assemblages, closely matching the morphology of the specimens recovered from the WPC, suggesting these collections originate from a single, as yet undescribed species (MJB, CBS, personal observations 2018).