Erbenochile

Erbenochile
Temporal range: Emsian to Eifelian
↓
E. erbeni
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Trilobita
Order:
Phacopida
Family:
Acastidae
Genus:
Erbenochile
Type species
Odontochile (Erbenochile) erbeni
Alberti, 1981
Species
  • E. erbeni Alberti, 1981 (type), = Odontochile (Erbenochile) erbeni
  • E. issoumourensis Chatterton & Gibb, 2010

Erbenochile is a genus of spinose phacopid trilobite, of the family Acastidae, found in Lower to Middle Devonian age rocks from Algeria and Morocco.[1][2] Originally described from an isolated pygidium (the posterior body part or shield),[1] the first complete articulated specimen of E. erbeni revealed the presence of extraordinarily tall eyes:

"Straight-sided towers of lenses... with [up to] 18 lenses in a vertical file"

— Fortey & Chatterton (2003)[3]

Number of lenses has been estimated at 560[3] or 450[4] incomplete preservation accounting for the uncertainty. A lens count of 18 lenses per file is unusually high (twice that of closely related genus) and accounts for the height of the eye, as opposed to a noticeable increase in the size of the individual lenses.[4] A recently found species (E. issoumourensis) has smaller eyes, with fewer files (33–35) and fewer lenses per file (13–14 max) than E. erbeni.[4] E. erbeni eyes allow full 360 degree coverage in the horizontal plane and were high enough to allow the trilobite to see backwards over its thorax. The presence of eye shades, blocking glare from over head, validates the suggestion that (at least some) trilobites were diurnal and not nocturnal,

"a detail of life habit which had previously been equivocal: Eyeshades are no use in the dark."

— Fortey & Chatterton (2003)[3]
  1. ^ a b Morzadec, P. (1995), "Erbenochile erbeni (Alberti), Trilobite de Dévonian inférieur d'Ougarta (Algerie).", Neues Jahrb. Geol. Paläontol. Monatsh., 10: 614–621, doi:10.1127/njgpm/1995/1995/614
  2. ^ Alberti, G.K.B. (1981), "Beziehungen zwischen "herzynischen" Trilobitenfauna NW-Marokko und Deutschland (Unter- und Mittel-Devon)", Natur und Museum, 110: 172–182
  3. ^ a b c Fortey, R.; Chatterton, B. (2003), "A Devonian Trilobite with an Eyeshade", Science, 301 (5640): 1689, doi:10.1126/science.1088713, PMID 14500973, S2CID 45993674
  4. ^ a b c Chatterton, B.; Fortey, R.; Brett, K.; Gibbs, S.; McKellar, R. (2006), "Trilobites from the Lower to Middle Devonian Timrhanrhart Formation, Jbel Gara el Zquilma, southern Morocco.", Palaeontographica Canadiana, 25, ISBN 1-897095-15-5