Nettapezoura
Extinct genus of arthropods
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Nettapezoura is a monotypic genus of fossil arthropod. The only known species is Nettapezoura basilika from the Marjum Formation of Utah, dating back to the Cambrian (Drumian) period.[1]
| Nettapezoura Temporal range: | |
|---|---|
| |
| Diagrammatic reconstruction as a habeliid | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Order: | †Habeliida |
| Genus: | †Nettapezoura Briggs et al., 2008[1] |
| Type species | |
| Nettapezoura basilika Briggs et al., 2008[1] | |
Morphology
Nettapezoura is known only by one specimen, UU 04083.02, which preserved the body in a parallel oblique angle, revealing more of its left dorsolateral side.[1]
The body comprise of a cephalon (head) and an 11-segmented trunk. All of the dorsal exoskeletons (tergites) does not have any well-defined boundaries between the axial region (vaulted middle section) and tergopleurae (lateral extensions). The cephalon is covered by a semicircular shield. The first 8 trunk segments are wide and possess triangular tergopleurae. The last 3 trunk segments are narrow and tube-like. Telson (tail) widen posteriorly and trifurcated into 3 short spines, resembling the webbed foot of a duck and hence the name Nettapezoura ("duck foot tail").[1]
Evidence of appendages are scarce. There are at least 2 pairs of thin, long appendages exposed from the cephalic shield. These were originally thought to be endopods (inner/lower branch),[1] but subsequently identified as exopods (outer/upper branch) like those of habeliids and Megachelicerax.[2] The trunk have at least 7, possibly 8 pairs of flap-like appendages, each possess an outer rami fringed by lamellae and an inner rami with leaf-like lobations. The last 3 trunk segments have no appendages.[1]
Classification
Similar to the co-described Dicranocaris, the taxonomic affinity of Nettapezoura is uncertain. Initially it was identified as an arachnomorph,[1] later a sister group of either Sidneyia or Dicranocaris.[3][4][5] Recent studies around 2020s suggest it is possibly a habeliid (stem chelicerate) alongside Dicranocaris and Messorocaris.[2]