Muensterelloidea

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Muensterelloidea
Temporal range: Early Jurassic–Campanian
Fossil of Muensterella scutellaris
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Cephalopoda
Order:
Octopoda
Suborder:
†Teudopseina
Superfamily:
†Muensterelloidea
Roger, 1952
Type species
†Muensterella scutellaris
(Münster, 1842) Schevill, 1950
Subgroups

Muensterelloidea is a superfamily (or clade) of stem-octopod cephalopods from the Early Jurassic to Late Cretaceous. Two families are currently identified, Muensterellidae, and Patelloctopodidae. The clade is the ancestral group from which modern octopus arose.

Description

Overall

Soft tissue anatomy within the Muensterelloidea is well-documented. Muenster (1842), who first recorded the holotype specimen of Muensterella, noted its egg-shaped anatomy and apparent lack of swimming fins.[1] Indeed, in all preserved specimens the same body structure is present, with all lacking a distinct swimming fin. Fuchs et al. (2003) suggested it possessed marginal fins, as a slight ridge along the sides of its body, when seen under oblique light, can be easily seen.[1]

All members of the Muensterelloidea possessed a roughly spoon-shaped section of the gladius known as the patella. This type of gladius is believed to be ancestral to the condition present in modern octopuses, in which the gladius is vestigial.[2]

Musculature

The musculature of muensterelloids is well-known from fossils. In certain specimens of Muensterella, bundles of muscle fibres are clearly visible.

funnel.[1]

Tentacles

In several specimens of Muensterella, four arm bases are known. In the holotype specimen, four ridges are known, indicating four pairs of arms. Fuchs et al. (2003) note there is no indication that a fifth pair was present. Only the very tips of the arms are missing, so the arms were likely rather short. They also note the likely presence of four short arm webs, around 1 cm beyond the arm bases.[1]

Phylogeny

Muensterelloidea consists of two families: Muensterellidae and Patelloctopodidae. The muensterelloids are characterized by having a roughly spoon-shaped end of the gladius called the patella. This type of gladius is likely ancestral to the gladius remnants of modern octopuses.[2] Cladistic analysis indicates that modern octopus are descended from the Patelloctopididae.[3]

References

  1. ^ a b c d e f Fuchs, D., Keupp, H., & Engeser, T. (2003). New records of soft parts of Muensterella scutellaris Muenster, 1842 (Coleoidea) from the Late Jurassic Plattenkalks of Eichstätt and their significance for octobrachian relationships. Berliner Paläobiologische Abhandlungen, 3, 101-111.
  2. ^
    S2CID 135245479
    .
  3. S2CID 198256507
    .
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