Fallotaspidoidea

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Fallotaspidoidea
Nevadia, from the Nevadiidae family

Nevadia, from the Nevadiidae family

Temporal occurrence
Lower Cambrian - Second Series
524 to 513 million years
Locations
  • worldwide
Systematics
Over trunk : Ecdysozoa
Trunk : Arthropod (arthropoda)
Class : Trilobites (Trilobita)
Order : Redlichiida
Subordination : Olenellina
Superfamily : Fallotaspidoidea
Scientific name
Fallotaspidoidea
Hupé , 1953

The Fallotaspidoidea ( Syn .: Fallotaspoidea) are with the Olenelloidea one of the two superfamilies from the trilobite suborder Olenellina . They appeared for the first time in the course of the Lower Cambrian and, in addition to the bigotinids Serrania gordaensis ( Spain ) and Hupetina antiqua ( Morocco ) with Profallotaspis jakutensis ( Siberia ) and Fritzaspis sp. ( Laurentia ) the first trilobites to appear in the fossil record . It was named after the French paleontologist Paul Fallot .

description

Cephalon : An essential and original character trait are the missing facial seams - comparable to the Olenelloidea. The glabella is cylindrical or slightly conical, the glabellar lobes L2 and L3 are simple. The eye ridge connects to the glabella on the front outside of the glabellar lobe LA. The glabellar furrows are deeply cut. The hypostome is natural.

Thorax : Has a large number of flat segments, spines occasionally attach to the spindle.

Pygidium : narrow, consists of only a few segments.

Distribution and occurrence

Distribution areas of Fallotaspidoidea are Laurentia (northwestern and southwestern Canada , southwestern United States , northern Greenland ), Baltica ( Sweden , Poland ), western Gondwana ( Morocco ), western Mongolia and northeastern and southeastern Siberia .

stratigraphy

The first appearance of the fallotaspidoid Profallotaspis jakutensis and Fritzaspis sp. defines the beginning of the second series (third stage) of the Cambrian in Siberia or in Laurentia.

Biostratigraphic trilobite zones were named after some representatives of the Fallotaspidoidea (sorted from young to old):

In Laurentia:

In Siberia:

  • Judomia zone
  • Fallotaspis zone or Repinaella zone
  • Profallotaspis jakutensis zone

Development history

Jell (2003) is of the opinion that the Fallotaspidoidea, as one of the first trilobites to appear in the fossil record, assume a basal position and that further side branches then split off from them. Compared to Fortey he takes the opinion that the hypostome in the Fallotaspidoidea was natant and not conterminant - the natant positioning therefore represents the original character. The also natant Ptychopariida emerged from the Fallotaspidoidea during the Cambrian . Furthermore, the Proasaphiscidae , the remaining Olenellina, the Redlichiina , the Odontopleurida and the Corynexochida split off from them - in these trilobite groups, however, the hypostome had migrated into the conterminant position.

In particular, Jell recognizes the following evolutionary side branches:

If Jell's ideas turn out to be correct, a polyphyletic composition of the orders Ptychopariida and Redlichiida will follow.

Systematics

The fallotaspidoid superfamily contains the following families:

Previously, the Daguinaspididae were also included, but they have now become a subfamily of the Fallotaspidae as Daguinaspinae .

Individual evidence

  1. ↑ Peter A. Jell (2003). Phylogeny of Early Cambrian Trilobites. In: Lane, PD, Siveter, DJ & Fortey, BA Trilobites and Their Relatives. Special Papers in Paleontology, 70, pp. 45-57. Paleontological Association

Web links

Commons : Fallotaspidoidea  - collection of images, videos and audio files

swell

  • Benton, MJ (1993): The Fossil Record 2 . Chapman & Hall
  • Lane, PD, Siveter, DJ & Fortey, RA (2003): Trilobites and Their Relatives . Special Papers in Paleontology, 70th Paleontological Association