Piloceratidae

Lateral and ventral views and cross-section of Cassinoceras explanator; note the greater preservation of the more mineralised siphuncle. Figures from Teichert (1964).

Belongs within: Endoceratoidea.

The Piloceratidae were a family of Lower Ordovician breviconic endocerid cephalopods. They had a large endocone-packed siphuncle occupying a large part of the shell.

Characters (from Teichert 1964): Breviconic, more or less strongly curved, rapidly expanding conches with compressed section; body chamber may have slightly contracted aperture. Siphuncle rapidly expanding, large; septal necks holochoanitic; endocones simple, complex system of endosiphuncular blades and endosiphofunicles occasionally present.

Piloceratidae
    |--Parapiloceras Obata 1939 T64
    |    `--*P. shimizui Obata 1939 T64
    |--Utoceras Ulrich, Foerste & Miller 1943 T64
    |    |--*U. coloradoense Ulrich, Foerste & Miller 1943 T64
    |    `--U. gleneyriense Ulrich, Foerste & Miller 1943 P68
    |--Cassinoceras Ulrich & Foerste 1936 T64
    |    |--*C. explanator (Whitfield 1886) [=Piloceras explanator] T64
    |    |--C. arkansasense Ulrich, Foerste & Miller 1943 P68
    |    |--C. grande Ulrich & Foerste 1943 P68
    |    `--C. wortheni T64
    |--Piloceras Salter in Murchison 1859 T64
    |    |--*P. invaginatum Salter in Murchison 1859 T64
    |    |--P. hornei P68
    |    |--P. manchuriense Endo 1932 P68
    |    |--P. saffordi Ulrich, Foerste & Miller 1943 P68
    |    `--P. tasmaniense T64
    `--Allopiloceras Ulrich & Foerste 1936 [incl. Trundleoceras Foerste 1938] T64
         |--*A. tennesseense Ulrich & Foerste 1936 T64
         |--A. affine Ulrich, Foerste & Miller 1943 P68
         |--A. baylorense Ulrich, Foerste & Miller 1943 P68
         |--A. breve Ulrich, Foerste & Miller 1943 P68
         |--A. compressum Ulrich, Foerste & Miller 1943 P68
         |--A. erectum Ulrich, Foerste & Miller 1943 P68
         |--A. sevierense Ulrich, Foerste & Miller 1943 P68
         |--A. subrectum Ulrich, Foerste & Miller 1943 P68
         |--A. subunguliforme Ulrich, Foerste & Miller 1943 P68
         `--A. unguliforme Ulrich, Foerste & Miller 1943 P68

*Type species of generic name indicated

REFERENCES

[P68] Purnell, L. R. 1968. Catalog of the Type Specimens of Invertebrate Fossils. Part I: Paleozoic Cephalopoda. United States National Museum Bulletin 262: 1-198.

[T64] Teichert, C. 1964. Endoceratoidea. In Treatise on Invertebrate Paleontology pt. K. Mollusca 3. Cephalopoda – General Features – Endoceratoidea – Actinoceratoidea – Nautiloidea – Bactritoidea (R. C. Moore, ed.) pp. K160-K189. The Geological Society of America and the University of Kansas Press.