''Hiltonius'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of cylindrical

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 in the family

Spirobolidae Spirobolidae is a family of millipedes in the order Spirobolida. The family consists of several genera with numerous species, and is commonly divided into the subfamilies Spirobolinae and Tylobolinae. Classification Subfamily Spirobolinae * '' ...

comprising 10 species ranging from the southwestern United States to Guatemala, with most species being found in Mexico. The genus was named by

Ralph Vary Chamberlin Ralph Vary Chamberlin (January 3, 1879October 31, 1967) was an American biologist, Ethnography, ethnographer, and historian from Salt Lake City, Utah. He was a faculty member of the University of Utah for over 25 years, where he helped establish ...

in 1918, after Professor William A. Hilton of

Pomona College Pomona College ( ) is a private university, private Liberal arts colleges in the United States, liberal arts college in Claremont, California. It was established in 1887 by a group of Congregationalism in the United States, Congregationalists ...

who collected the

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

of ''H. pulchrus''.

Description

Species of ''Hiltonius'' range from long and wide, with 40–49 body segments. The eyes are composed of patches of

ocelli A simple eye or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

, widely spaced, containing 21 to 37 ocelli per patch. The legs are short, usually not reaching the sides of the body when held horizontally. Like many other spirobolids, color ranges from brown to nearly black, and thin bands of red or yellow may occur on the rear margins of each segment.

Species

''Hiltonius'' contains 10 named species. Some have wide distributions while others are known only from the type locality- the place where the

s were initially discovered. The northernmost species are ''H. pulchrus'' and ''H. carpinus'', ranging into southern California and northern Arizona, respectively. A

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of ''H. carpinus'' occurs in an isolated population in

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

Similar species

''Hiltonius'' co-occurs with some species of ''

Tylobolus ''Tylobolus'' is a genus of millipedes in the order Spirobolida with seven known species found in western North America. It is in the family Spirobolidae, and is the type genus of the subfamily Tylobolinae. The genus was named by Orator F. Cook ...

'' in southern California. ''Tylobolus'' species can be distinguished by larger maximum size (up to 92 mm or 3.6 in long), having more ocelli per eye patch (27–50), a larger hooked process on the coxa of the third leg in males, and in details of the

gonopods Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipe ...

, male reproductive structures.

References

External links

''Hiltonius''
on

BugGuide BugGuide (or BugGuide.net) is a website and online community of naturalists, both amateur and professional, who share observations of arthropods such as insects, spiders, and other related creatures. The website consists of informational guide p ...

{{Taxonbar, from=Q4255897 Spirobolida Millipedes of North America