Peytoia infercambriensis

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"Cassubia" redirects here. For the region in Poland, see Kashubia.

Peytoia infercambriensis
Temporal range: Cambrian Stage 3
Interpretive drawing of holotype specimen of P. infercambriensis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: †Dinocaridida
Order: †Radiodonta
Family: †Hurdiidae
Genus: †Peytoia
Species:
†P. infercambriensis
Binomial name
†Peytoia infercambriensis
(Lendzion, 1975)
Synonyms
  • Cassubia infercambriensis (Lendzion, 1975)
  • Pomerania infercambriensis Lendzion, 1975 (preoccupied)

Peytoia infercambriensis is a species of

radiodont in the genus Peytoia
.

P. infercambriensis is the geologically oldest known radiodont; its remains date to the

junior synonym
of Peytoia.

History of study

Discovery and naming

The holotype—and only—specimen was recovered from the

arthropod.[1] In 1977, Lendzion discovered that the name Pomerania had already been used by an ammonoid, so she renamed the genus Cassubia, after the Kaszuby region of where the specimen was found.[2]

Reinterpretations

In 1988, Jerzy Dzik and Kazimiera Lendzion reinterpreted the specimen as representing the appendage of an

anomalocaridid. They interpreted both the "thorax" and "chelicera" as both parts of a single elongate appendage, similar to that of Anomalocaris.[3] Some researchers, such as Simon Conway Morris, suggested that it may even be synonymous with Anomalocaris itself.[4] In 1995, E. L. Bousfield proposed a taxonomic arrangement of early arthropods in which Cassubia and Anomalocaris were assigned to the same class, Anomalocaridea, but Cassubia was given a subclass of its own, Cassubiata. Though recognizing Cassubia as related to Anomalocaris, Bousfield followed Lendzion's original interpretation of the specimen as comprising a short appendage and long body.[5] When the radiodont Tamisiocaris was discovered by Allison Daley and John Peel in 2010, they took note of its apparent similarity to Cassubia infercambriensis, as it had been interpreted by Dzik and Lendzion.[6] In 2012, Joachim Haug et al. interpreted Cassubia as similar to the megacheiran Occacaris.[7]

These diverse interpretations led Alison Daley and David Legg to restudy the original specimen. They concluded that the specimen did indeed consist of both a body and appendage, but that they did not belong to the same animal. Rather, the body was that of an indeterminate arthropod, while the appendage was that of a radiodont similar to Peytoia nathorsti. As such, they synonymized Cassubia with Peytoia, making the new combination Peytoia infercambriensis.[8]

Description

Peytoia infercambriensis differed from its close relative Peytoia nathorsti in several characteristics of its frontal appendage, the only part of its anatomy known. The ventral spines are only half as wide as the associated podomere, and are estimated to have borne approximately 24 tightly-spaced auxiliary spines. The endites decrease sharply in length, such that the distalmost endite is only a quarter the length of the proximalmost.[8]

Paleoecology

The Zawiszyn Formation, in which the only known specimen of Peytoia infercambriensis was found, dates back to the

small shelly fossil Mobergella is abundant in the rock layers where Liwia and P. infercambriensis are found.[3] The depositional environment was a shallower-water environment than typical of places with Burgess Shale-type preservation.[4]

References

  1. ^ a b Lendzion, Kazimiera (1975). "Fauna of the Mobergella zone in the Polish Lower Cambrian". 19 (2): 237–242. {{cite journal}}: Cite journal requires |journal= (help)
  2. ^ Lendzion, Kazimiera (1977). "Cassubia - a new generic name for Pomerania Lendzion, 1975". Geological Quarterly. 21 (1).
  3. ^
    doi:10.1111/j.1502-3931.1988.tb01749.x
    .
  4. ^
    S2CID 130070181
    .
  5. ISSN 1189-9905
    .
  6. S2CID 130637114
    .
  7. S2CID 82841481
    .
  8. ^
    S2CID 130745134
    .
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