Xyloiuloidea is an extinct superfamily of

millipede Millipedes (originating from the Latin , "thousand", and , "foot") are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derive ...

s that existed from the Lower Devonian through the Upper Pennsylvanian period in Europe and North America.

Description

Xyloiuloids are more or less cylindrical, with sternites, pleurites, and tergites of each

body segment Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other. This article focuses on the segmentation of animal body plans, specifica ...

fused into a complete ring. Adults possess 40 to 50 body rings. The legs are no longer than half the height of the body. The body surface is marked by small parallel grooves (striations), which vary in surface coverage between xyloiuloid families.

Taxonomy

Xyloiuloidea comprises four families: *† Gaspestriidae *† Nyraniidae *† Plagiascetidae *† Xyloiulidae The taxonomic history of Xyloiuloidea begins with Orator F. Cook designating the family Xyloiulidae in 1895. In 1969, Richard L. Hoffman established the families Nyraniidae and Plagiascetidae, and placed all three extinct families in the extant (still-living) order

Spirobolida Spirobolida is an Order (biology), order of "round-backed" millipedes containing approximately 500 species in 12 family (biology), families. Its members are distinguished by the presence of a "pronounced Suture (anatomy), suture that runs "verti ...

, as suborder "Xyloiulidea".Hoffman, Richard L., 1969. Myriapoda, exclusive of Insecta. R572–R606. In: Moore, R.C. (Ed.), ''Treatise on Invertebrate Paleontology'', Part R, Vol. 2. Geological Society of America and University of Kansas Press, Lawrence, KS. In 2006, two new species were described and placed in the new family Gaspestriidae, and group was reassigned as a superfamily of uncertain status (''

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'') within the juliform millipedes, a group that includes the cylindrical, fused-bodied orders Spirobolida,

Spirostreptida Spirostreptida is an order of long, cylindrical millipedes. There are approximately 1000 described species, making Spirostreptida the third largest order of millipedes after Polydesmida and Chordeumatida. Description Spirostreptida are generall ...

, and

Julida Julida is an order of millipedes. Members are mostly small and cylindrical, typically ranging from in length. Eyes may be present or absent, and in mature males of many species, the first pair of legs is modified into hook-like structures. Addit ...

References

Millipede taxonomy Arthropod superfamilies Carboniferous myriapods Devonian myriapods Carboniferous arthropods of Europe Carboniferous arthropods of North America Devonian arthropods of Europe Devonian arthropods of North America Early Devonian first appearances Pennsylvanian extinctions {{Paleo-myriapod-stub