844
Journal of Paleontology 92(5):838–849
Figure 6. Soligorskopterus tchepeliensis n. gen. n. sp., paratype BKM 942; prosomal appendage II: (1) specimen photograph; (2) interpretive drawing. Abbreviations as in Figure 3. Scale bar=10mm.
Figure 5. Soligorskopterus tchepeliensis n. gen. n. sp., paratype BSUM P-276/P-170; prosoma with appendage pair VI viewed from the ventral surface. Scale bar=10mm.
notch where they join, which indicates they might have been separate or only partially fused. The metasoma is preserved in slightly rougher condition
than the mesosoma. The metasomal segments narrow regularly posteriorly: the seventh segment is 14mm in length, 62mm in width across its posterior; the eighth segment is 14mm in length, 58mm in width; the ninth segment is 15mm in length, 55mmin width; the tenth segment is 16mmin length, 50mmin width; the eleventh segment is 18mm in length, 40mm in width; and the pretelson is 32mm in length, 18mm in width. The cuticular ornament of the metasomal sternites comprises small semilunate and acicular scales, which enlarge and form paired ridges on segments 10–12. Small epimera are present at the posterolateral margins of the metasomal segments. The telson is poorly preserved and present as only a few small fragments of cuticle posterior to the pretelson. The second paratype (BSUM P-276/P-170; Fig. 5) is
represented by a fragmentary prosoma comprising the outline of the prosomal carapace with the prosomal appendage coxa, metastoma, and a complete paired appendage VI. The prosoma is horseshoe-shaped with a length of 75mm and a width of 83mm, resulting in a length/width ratio of 0.90. The narrow 2–3mm wide marginal rim extends around the anterior and lateral edge of the carapace and tapers to its posterior. The metastoma is petaloid in shape, narrow, with relatively straight sides and a shallow anterior notch. The cuticle at its posterior is
absent but imprints in the sediment suggest it had a truncated, flattened posterior margin. Paired appendage VI is preserved in its entirety, revealing a narrow coxa with no anteriorly expanded
ear. The appendages are long and nonspiniferous, with the fourth podomere being the longest and all subsequent podo- meres shortening consecutively. No modified podomere 7a is present. Distal podomeres are not expanded into a swimming paddle. The anterodistal margin of podomere VI-8 is drawn out into a long projection, extending for three-fifths the length of podomere VI-9. The ornamentation on the appendages comprises small semilunate scales, with a thickened border of scales along the lateral podomere margins. Dense scale ornament is also visible on the coxa. The final paratype (BKM 942; Fig. 6) is a partially
exfoliated but fairly complete prosomal appendage II. The appendage tapers in width from 10mm proximally to 3mm distally; its total length is 75mm and it is comprised of six podomeres, including the coxa. The coxa and second podomere are devoid of armature, whereas podomeres II-3–II-5 bear
numerous short (5–8mm) and thin (0.9–1.1mm) spines, at least five per podomere. These spines bear slight striations running along their length. The surface of the first two podomeres of the appendage has sculpture in the form of dense semilunate and acicular scales.
Etymology.—The species name is derived from the village of Tchepeli, near where one of the eurypterid specimens was found.
Remarks.—The new eurypterid (Fig. 7) exhibits a number of characteristics that place it firmly within the stylonurines. The most obvious of these is the retention of prosomal appendage VI as awalking limb lacking amodified podomere 7a, however the assignment is also supported by the lack of an expanded ear on coxa VI, the transverse suture on the prosomal ventral plates, and the possession of a visible anterior opercular plate (Lamsdell et al., 2010b). Within the Stylonurina, Soli- gorskopterus n. gen. exhibits closest affinities to the Stylo- nuroidea, lacking as it does the spiniferous appendage V characteristic of Kokomopteroidea (Tetlie, 2008; Lamsdell et al., 2010b) and the cleft posterior metastoma and sweep- feeding modifications seen in Mycteropoidea (Lamsdell et al., 2009; Lamsdell, 2013). The multiple spines per podomere on appendages II–IV also preclude the new species from assign- ment to Rhenopteroidea (Lamsdell et al., 2010a). Multiple spines per podomere are, however, known from some members
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