Sellanucheza tenebra (Hoffman, 1961)
Fig. 1
Szechuanella tenebra Hoffman 1961: 535 (D).
Szechuanella tenebra – Hoffman 1963: 586 (M, K); Jeekel 1968: 75 (M); Wang and Mauriès 1996: 87 (L); Sierwald 2009: 125 (M).
Sellanucheza tenebra – Enghoff et al. 2004: 39 (M); Nguyen and Sierwald 2013: 1296 (L); Golovatch 2013 a: 22 (M, K); 2013 b: 330 (M, K).
Distribution.
China, Sichuan Province, Wushan, 31.07°N, 109.52°E (Hoffman 1961).
Remarks.
Sellanucheza tenebra was originally described as the type species of the genus Szechuanella Hoffman, 1961, based on a male holotype from Wushan, Sichuan Province, China (Hoffman 1961). However, as the name Szechuanella Hoffman, 1961 was found to be preoccupied by a trilobite genus (Zhang and Fan 1960), Enghoff et al. (2004) proposed Sellanucheza as a replacement name. Somatically, this species is unique among congeners due to the strongly reduced paraterga on rings 3–19, these being represented only by very faint bulges devoid of any delimiting sulci. This character makes S. tenebra clearly distinguished from all other known species, in which the paraterga, even if poorly developed, are always demarcated by at least a dorsal sulcus. In addition, male sternum 5 is characteristic in bearing a large, hemispherical lobe between coxae 4. Regarding the gonopod, S. tenebra is characterized by a long, strongly coiled solenophore (sph) which is subequal in length to a subunciform femorite (fe) (Fig. 1 A). Most notably, the gonopod bears a conspicuous, long and acute process pa directed ventrad, as well as a small, acute, basal process pb (Fig. 1 A, B). The solenophore tip is bifid, consisting of two large, rounded, subequal, hyaline, spatulate lobules (Fig. 1 A, B). These features make S. tenebra clearly distinguished from congeners such as S. variata or S. grandis, which typically show a relatively shorter or differently shaped solenophore. The species remains known only from the type locality in Sichuan Province, China.
Publication Date: 2026-06-23