Original diagnosis by Foster (1969: 383): ''Prostomium triangular, flared anteriorly, lacking frontal horns, ... [details]
Western Atlantic Ocean: North Carolina to Puerto Rico; Gulf of Mexico. [details]
Western Atlantic Ocean: North Carolina to the Gulf of Mexico (Alabama; Texas). [details]
The specific epithet mayaguezensis refers to the type locality of the species, Mayagüez (Puerto Rico, Caribbean Sea). [details]
The name Apoprionospio is composed by the prefix of Greek origin apo-, meaning 'away from' or 'separate', and the ... [details]
The species is named for Dr. John H. Day (b. Sussex, England, 25 August 1909 - d. Knysna, South Africa, 24 April ... [details]
Feminine. See the etymology notes for a full discussion of some complexities [details]
Indeterminable. According to Foster (1969: 388), ''Prionospio nova, based on an incomplete specimen, is considered ... [details]
Off Mayagüez, Puerto Rico, Caribbean Sea (gazetteer estimate 18.2º, -67.16º), 10 feet depth (= about 3 m). [details]
Off Beaufort, North Carolina, Atlantic coast of the USA (gazetteer estimate 34.4º, -76.7º). [details]
Holotype (USNM 39485) and paratype (USNM 39486) deposited in the Smithsonian Institution, Washington D.C., USA. [details]