Ramphoprionidae

Reconstructed jaw apparatus of Ramphoprion elongatus, from Eriksson (2002).

Belongs within: Aciculata.

The Ramphoprionidae are a group of annelid worms known from the Ordovician and Silurian periods from their fossilised jaws only.

Characters (from Eriksson 2002): Maxillary apparatus asymmetrical; one pair of dorsally flattened, subrectangular carriers present posteriorly, followed by one pair of strongly asymmetrical first maxillae with denticulated dorsal side and slightly enclosed myocoele; short, subrectangular or subtrapezoid basal plate fitted into bight of right first maxilla; left first maxilla and basal plate both with wide transverse posterior margin; anterior maxillae (MII to MIV known) somewhat sickle-shaped with rounded anterior margin; lateral teeth present; laeobasal plate and intercalary tooth absent.

<==Ramphoprionidae
    |--Megaramphoprion Eriksson 2001 E02
    |    `--M. magnus E02
    |--Ramphoprion Kielan-Jaworowska 1962 E02
    |    |--R. elongatus E02
    |    `--R. gotlandensis E02
    |--Pararamphoprion Männil & Zaslavskaya 1985 E02
    |    |--P. matusevichi Männil & Zaslavskaya 1985 E02
    |    `--P. nordicus Männil & Zaslavskaya 1985 E02
    `--Protarabellites Stauffer 1933 E02
         |--*P. humilis Stauffer 1933 H62
         |--P. rectangularis E02
         |--P. staufferi E02
         `--P. triangularis E02

*Type species of generic name indicated

REFERENCES

[E02] Eriksson, M. 2002. The palaeobiogeography of Silurian ramphoprionid polychaete annelids. Palaeontology 45 (5): 985–996.

[H62] Howell, B. F. 1962. Worms. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W144–W177. Geological Society of America, and University of Kansas Press.