Anoria? bessus (Walcott, 1916a), 1935

Foster, John R., 2022, Continuous character variation within the Glossopleura-Anoria-Sonoraspis plexus: Dolichometopid trilobites from the Cadiz Formation (Cambrian: Miaolingian, Wuliuan), California, Palaeontologia Electronica (a 18) 25 (2), pp. 1-25 : 19

publication ID

https://doi.org/ 10.26879/1173

persistent identifier

https://treatment.plazi.org/id/1D3087BE-2047-FFA1-8C17-13022A9AF9B5

treatment provided by

Felipe

scientific name

Anoria? bessus (Walcott, 1916a)
status

 

Anoria? bessus (Walcott, 1916a)

Dolichometopus? bessus Walcott, 1916a, p. 362 – 363, pl. 51, figs. 3, 3a–c.

Anoria bessus (Walcott) Resser, 1935, p. 10 , p. 54, pl. 9, fig. 2.

Anoria baton (part) Schwimmer, 1973, pl. 6, fig. 3.

Type specimens. USNM 62699 About USNM , nearly complete specimen ; USNM 62700 About USNM , pygidium ; USNM 62701 About USNM , cephalon with hypostome .

Occurrence. Gordon Shale, Montana; Bright Angel Formation, Grand Canyon (Grand Wash Cliffs), Arizona; Glossopleura Assemblage Biozone, Interval Biozone (Morgan, 2021) undesignated, (Wuliuan, Miaolingian).

Material examined. USNM 62699, USNM 62700, USNM 62701, DMNH EPI.42915, DMNH EPI.42916, USNM uncataloged (in Schwimmer, 1973).

Remarks. Species characterized by short to long eyes, reduced oval pygidium smaller than cephalon, and moderately elongate pleural spines on all thoracic segments. This latter character contrasts with the short pleural spines of most species of Glossopleura and the elongate fifth thoracic pleural spines of G. lodensis and the type material of Anoria tontoensis . These features are pronounced in USNM 62699 and the uncataloged specimen illustrated by Schwimmer (1973). Despite qualitatively moderately short eyes in the Gordon Shale specimens, most specimens have moderate to long eyes except USNM 62699 (EL/GL of 0.298 versus 0.428 in Schwimmer’s, 1973, USNM uncataloged and 0.446 in DMNH EPI.42915). Thus, all but one specimen featuring moderately elongate pleural spines and a small, oval pygidium from the Gordon and Bright Angel formations, typical of Anoria bessus , actually have elongate eyes that fit within the range of Glossopleura . Because the single anomalous, short-eyed specimen (USNM 62699) is the most complete of the cotypes, all the studied material here is designated Anoria? bessus . The question of whether the species is better placed in Glossopleura (despite the short-eyed USNM 62699 and considering the results of this study regarding eye length) is left for a separate investigation.

USNM

Smithsonian Institution, National Museum of Natural History

DMNH

Delaware Museum of Natural History

Kingdom

Animalia

Phylum

Arthropoda

Class

Trilobita

Order

Corynexochida

Family

Dolichometopidae

Genus

Anoria

Loc

Anoria? bessus (Walcott, 1916a)

Foster, John R. 2022
2022
Loc

Anoria bessus (Walcott)

Resser 1935: 10
1935
Loc

Anoria baton

Resser 1935
1935
Loc

Dolichometopus? bessus

Walcott 1916: 362
1916
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