Palaeoisopus
| Palaeoisopus Temporal range:
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|---|---|
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| Fossil | |
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| Reconstruction | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | Arthropoda |
| Subphylum: | |
| Class: | Pycnogonida |
| Order: | †Palaeoisopoda
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| Family: | †Palaeoisopodidae Dubinin, 1957
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| Genus: | †Palaeoisopus Broili, 1928
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| Species: | †P. problematicus
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| Binomial name | |
| †Palaeoisopus problematicus Broili, 1928
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Palaeoisopus is a
Lower Devonian Hunsrück Slate of Germany.[1] It have several characters unusual for a pycnogonid, such as swimming legs with alternating size, medially-arranged eyes, and most significantly, a long, segmented abdomen, which were highly reduced in modern counterparts.[1]
Morphology
Palaeoisopus is a large
chelicerates, always located at the ventral boundary of abdomen and telson), the latter was also suggest to be a fusion of 5th abdominal somite and the original telson.[1]
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Fossil of Palaeoisopus, showing the long, fully-extended 1st leg pair. -
Ventral fossil, showing full set of appendages. -
Fossil compose of 3 individuals, showing dorsal morphology.
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Medial to the anterodorsal margin of cephalon was an eye-bearing ocular tubercle. Unlike the paired 4-eyed arrangement of most pycnogonids, it compose of a pair of large eyes and 2 smaller eyes that arranged anteroposteriorly in a midline.setae arrangement, 4 flatten distal podomeres instead of 5).[1]
Paleoecology
The large eyes, robust chelifores and oar-like legs suggest that Paleoisopus was a
Phylogeny
While some analysis placing Palaeoisopus within a derived position,