Tesselacauda Ross 1951
- Dataset
- Revision of the Early Ordovician (late Tremadocian; Stairsian) cheirurid trilobite Tesselacauda Ross, with species from the Great Basin, western USA
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Trilobita
- order
- Phacopida
- family
- Pliomeridae
- genus
- Tesselacauda
materials_examined
Material. Assigned specimens SUI 147587 – 147594, from Section MME 36.4 m, Fillmore Formation (upper Tremadocian; Stairsian; Rossaspis leboni Zone), southern Confusion Range, Ibex area, Millard County, western Utah. Discussion. Specimens retrieved from Section MME 36.4 m are from lower in the same zone as those of T. morrisoni. The sample from MME 36.4 m is in general fragmentary and sparse, but most species seem to occur also in the assemblage at MME 49.8 m. The Tesselacauda specimens, however, definitely do not belong to T. morrisoni. The dorsal pygidial surfaces of most specimens are almost completely effaced, and lack the clusters of tubercles on the distal parts of the pleurae which characterize T. morrisoni. The terminal piece, while relatively large, is about as wide as it is long, whereas those of pygidia of T. morrisoni are much longer than wide. The MME 36.4 m material seems to represent a poorly known but distinct species, the oldest member of the genus thus far recovered.