Agraulos Hawle & Corda, 1847

Unger, Tanja, Hildenbrand, Anne, Stinnesbeck, Wolfgang & Austermann, Gregor, 2022, Biostratigraphy and taxonomy of polymerid trilobites of the Manuels River Formation (Drumian, middle Cambrian), Newfoundland, Canada, Geodiversitas 44 (33), pp. 1051-1087 : 1055-1056

Genus Agraulos Hawle & Corda, 1847

Agraulos Hawle & Corda, 1847: 26 , 27. —

Type species: Arion ceticephalus Barrande, 1846 , designated by Miller (1889).

Arion Barrande, 1846: 12 , 13. —

Type species: Arion ceticephalus Barrande, 1846 , by monotypy ( Barrande 1846).

Arionides – Barrande 1847: 391.

Herse Hawle & Corda, 1847: 19 . —

Type species: Herse neubergii Hawle & Corda, 1847 , by monotypy ( Hawle & Corda 1847).

Arionellus – Barrande 1852b: 404.

DIAGNOSIS. — Cranidium parabolic and domed; exoskeleton thick; glabella domed, equal-sided to trapezoidal; preglabellar field long; thorax of 16 segments (based onLake 1932; Harrington et al. 1959; Fletcher 2017, with modifications).

REMARKS

The genus was first described by Barrande (1846) as Arion . As the name Arion was occupied by a genus of gastropods, Hawle & Corda (1847) renamed the trilobite Arion to Agraulos . Barrande (1847) corrected his mistake and renamed the genus to Arionides . Barrande (1852b) re-renamed the genus to Arionellus , as in his opinion Arionides might still be challenged by other authors. He rejected Agraulos Hawle & Corda (1847) as he found the name too similar to Agraulis , a genus of butterflies. Nevertheless, Pompeckj (1896) and Lake (1932) stated that a similarity of names, i.e. Agraulos and Agraulis , was not an adequate reason to reject the name given by Hawle & Corda (1947). Therefore, Agraulos is now the name established for this genus. Lake (1932) mentioned that Hawle & Corda (1847) described juvenile forms of Agraulos as the new genus Herse .

The genus Agraulos is closely related to Skreiaspis Růžička, 1946 , but differs by a longer preglabellar field ( Harrington et al. 1959). Agraulos is here included in the family Agraulidae Howell, 1937 , following e.g., Harrington et al. (1959), Martin & Dean (1988), Jell & Adrain (2002), Bentley & Jago (2004) and Weidner & Nielsen (2014). The limiting of Agraulidae to a subfamily of the family Solenopleuridae Angelin, 1854 , as proposed by Fletcher (2017), is not followed herein. This latter author suggested that the same characters that support Agraulidae , as defined by Bentley & Jago (2004), are also seen in Parasolenopleura aculeata ( Angelin, 1851) , the reference species of the Solenopleuridae .However, the Solenopleuridae has a deep occipital furrow and a narrow border ( Harrington et al. 1959), which differ from a weakly to effaced occipital furrow and presence of a preglabellar field, as characteristically seen in the Agraulidae ( Harrington et al. 1959; Bentley & Jago 2004).