948


Journal of Paleontology 91(5):933–959


2015 Oryctocarella sibirica; Peng et al., p. 89, pl. 1, fig. 5. 2017 Oryctocarella sibirica; Korovnikov and Novozhilova, p. 267, pl. 5, figs. 1–7; text-fig. 3.a, 3.b.


Neotype.—The original type material, including the holotype (an exoskeleton) and more than 10 additional variously complete exoskeletions, of which five were figured by Tomashpolskaya and Karpinski (1961, pl. 1, figs. 1, 3–6), is apparently lost. An incomplete cranidium, CSGM 2075/2 (Fig. 6.1) from a recent collection of topotypes, is designated as the neotype (see discussion below).


Diagnosis.—Oryctocarella with subrectangular or cylindrical glabella; preglabellar field absent; palpebral ridge faint, close to anterior border furrow; palpebral lobe located anterior to gla- bellar mid-length, with posterior tip opposite mid-length of L2 (~34% of cephalic length); palpebral area narrower than gla- bella; posterior section of facial suture nearly transverse; crani- dial posterior border widens abaxially. Thorax with nine segments; anterior pleural band equal to or slightly shorter than posterior band. Pygidial margin may have slight inward curva- ture medially, but lacks medial notch. Dorsal surface densely granulose.


Occurrence.—Known only from outcrop 863, Region of Dolgii Mys Mountain, Batenevsky Ridge, Kuznetsk Alatau, Altay- Sayan Foldbelt, southwestern Siberia, Russia; basal Amgan Stage (traditional middle Cambrian) of the Siberian regional stratigraphy, corresponding to the Cambrian Stage 4.


Materials.—Two unfigured cranidia (CSGM2075/16, CSGM 2075/17) and three specimens illustrated by Korovnikov and Novozhilova (2017), which include an incomplete cranidium (CSGM2075/2), an incomplete exoskeleton (CSGM2075/5), and a thoracopygon (CSGM2075/6); all in a single collection from the basal Amgan Stage of Siberian regional stratigraphy (provisional Cambrian Stage 4), Region of Dolgii Mys (Long Cape) Mountain, Batenevsky Ridge, Kuznetsk Alatau, Altay- Sayan Foldbelt, Russia, the type locality of the species.


Remarks.—The type species of Oryctocarella, Oryctocara sibirica, was originally based on a single exoskeleton, the


holotype (Tomashpolskaya in Khalfin, 1960, p. 199, pl. 23, fig. 5, No. 863(1)58; refigured in Tomashpolskaya and Karpinski, 1961, pl. 1, fig. 2) from the traditional lower middle Cambrian,


Region of Dolgii Mys Mountain, Batenevsky Ridge, Kuznetsk Alatau, southwestern Siberia, Russia; by monotypy. When Tomashpolskaya and Karpinski (1961) erected the genus Oryctocarella, with Oryctocara sibirica as its type species, addi- tional specimens from the same collection as the holotype were illustrated (Tomashpolskaya and Karpinski, 1961, pl. 1, figs. 1, 3–6). At least 10 variously complete exoskeletons were in the collection with the holotype (see Tomashpolskaya and Karpinski, 1961). The original material, which was housed at the Geological Museum of the Tomsk Polytechnic Institute (TPI, now Tomsk Polytechnic University), now appears to be lost. A search on our request by I. Korovnikov, Novosibirsk through the collections at Tomsk Polytechnic University, failed to recover any material of O. sibirica from Tomashpolskaya’s original collection. Because of the absence of the original material, a neotype (Fig. 6.1) is selected from a collection of topotypes collected by I. Korovnikov from Tomashpolskaya’s original locality in the Dolgii Mys Mountain region. This new material (Korovnikov and Novozhilova, 2017, pl. 5, figs. 1–7; Fig. 6), although not well pre- served, is sufficient to demonstrate most morphological characters of O. sibirica,and that Oryctocarella should be regarded as a valid genus.


Oryctocarella sibirica was originally reported to have eight


thoracic segments. One of the topotypes (Fig. 6.5, 6.6) shows that the thorax contains at least nine segments. In this specimen the axial ring of the ninth segment is present, but broken. Differences between the type species of Oryctocarella,


O. sibirica, and other species now referred to the genus, Oryctocarella balangensis (Qian and Lin in Yin and Li, 1978) and O. duyunensis (Qian, 1961), are discussed below.


Oryctocarella balangensis (Lu and Qian in Yin and Li, 1978) Figure 7


1961


1978 1980


1980 1980


Arthricocephalus duyunensis Qian (part), p. 97,


pl. 1, fig. 20, pl. 2, fig. 6; non pl. 1, fig. 19, pl. 2, figs. 5, 7, 8, 10, ?fig. 9.


Arthricocephalus (Arthricocephalites) balangensis Lu and Qian in Yin and Li, p. 442, pl. 157, fig. 10. Arthricocephalus (Arthricocephalites) xinzhaiheensis


Qian; Zhang et al., p. 276, pl. 93, fig. 1; non pl. 92, figs.5,6.


Arthricocephalus (Arthricocephalites) balangensis; Zhang et al., p. 277, pl. 93, figs. 2, 3.


Arthricocephalus (Arthricocephalites) xiaosaiensis Qian in Zhang et al. (part), p. 278, pl. 93, fig. 7,


and Li (1978, pl. 157, fig.10), GY210; (2) enlargement of part of cephalon in 1;(3) NIGP 38241, cephalon previously illustrated by Zhang et al. (1980, pl. 93, fig. 3), GY222; (4) NIGP 164947, incomplete cranidium on same slab as specimen in 8, XS-Xiao152; (5) NIGP 11485, cranidium previously illustrated by Qian (1961, pl. 1, fig. 20) as Arthricocephalus chauveaui, GY206; (6) NIGP 11492, cranidium previously illustrated by Qian (1961, pl. 2, fig. 6) as Arthricocephalus chauveaui, GY204; (7) NIGP 38239, cranidium previously illustrated by Zhang et al. (1980, pl. 93, fig. 1) as Arthricocephalus (Arthricocephalites) xinzhaiheensis, GY214; (8) NIGP 38244, cranidium previously illustrated by Zhang et al. (1980, pl. 93, fig. 7) as one of two ‘holotypes’ of Arthricocephalus (Arthricocephalites) xiaosaiensis Qian, retrodeformation with inferred strain ellipse, XS-Xiao152; (9) NIGP 38248, cranidium previously illustrated by Qian in Zhang et al. (1980, pl. 94, fig. 3) as one of two ‘holotypes’ of Arthricocephalus (Arthricocephalites) xiaosaiensis Qian, XS-Xiao152; (10) NIGP 38251, pygidium with six thoracic segments, previously illustrated by Zhang et al. (1980, pl. 94, fig. 6) as Arthricocephalus (Arthricocephalites) xiaosaiensis, XS-Xiao152; (11, 13) NIGP 164948, external mold of incomplete exoskeleton, two views, reversed images, XS-Xiao152, in association with the pygidium in 10; (12) NIGP 164949, reversed image of external mold of thoracopygon, XS-Xiao152, on same slab as the NIGP 38251 pygidium in 10 and thoracopygon in 11. All scale bars represent 1.0mm.


Figure 7. Oryctocarella balangensis (Lu and Qian in Yin and Li, 1978) from the Balang Formation in southeastern (1–3, 5) and eastern (4, 6–13) Guizhou, South China; all in dorsal view. White arrowhead indicates the posterior margin of thorax; arrowhead with black outline indicates the posterior margin of partially released segment of transitory pygidium; b = border, d = doublure: (1) holotype NIGP 38240, incomplete exoskeleton, original of Lu and Qian in Yin


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