# Aponileus

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***Aponileus*** is an [extinct](/source/Extinct) [genus](/source/Genus) of [trilobites](/source/Trilobite). Chung-Hung Hu [circumscribed](/source/Circumscription_(taxonomy)) the genus in 1963. The genus was once considered a [junior subjective synonym](/source/Junior_subjective_synonym) of the genus *[Psephosthenaspis](/source/Psephosthenaspis)* but it is considered to be a distinct genus again. As of 2021, fossils have been found in Greenland, Texas, and Utah. They all date to the Upper [Floian](/source/Floian) (Blackhillsian) within the [Ordovician](/source/Ordovician) Period.

## Taxonomic history

*Aponileus* was initially [circumscribed](/source/Circumscription_(taxonomy)) by Chung-Hung Hu in 1963.[1] The [type species](/source/Type_species) is *A. latus*, also [described](/source/Species_description) by Hu in 1963. The type material was poorly preserved.[2] Hu initially said that *Aponileus* is "most like *[Nileus](/source/Nileus)*",[3] i.e., treating it as a [nileid](/source/Nileidae).[4] Subsequently, this genus received "virtually no mention" in the trilobite literature for many years,[5] aside from C. P. Hughes's 1979 assessment that two specimens which Lehi F. Hintze had tentatively assigned to *[Barrandia](/source/Barrandia)* in 1953[6] should be placed in *Aponileus*.[7] In 2003, Jonathan M. Adrain [synonymized](/source/Synonym_(taxonomy)) *Aponileus* with *[Psephosthenaspis](/source/Psephosthenaspis)*, placing it in the family [Bathyuridae](/source/Bathyuridae).[8]

In 2012, Adrain and Neo E. B. McAdams treated *Aponileus* as a distinct genus within Bathyuridae.[9] They also included the species *A. glaber*,[10][11] which Christian Poulsen had initially described in the genus *[Bolbocephalus](/source/Bolbocephalus)* in 1927. Adrain and McAdams placed five newly described species in *Aponilus*, namely *A. aasei*, *A. belkaae*, *A. laikaae*, *A. strelkaae*, and *A. ugolekae*; they also tentatively assigned a further newly described species to this genus: *A.*? *veterokae*.[9] While they believed the "best supported current hypotheses" was to place it in *Aponileus*, they acknowledged it is "very different from all other species included in the genus" and hence "assign[ed] the species only with question".[12]

Various [specific epithets](/source/Specific_epithet) are named after [Soviet space dogs](/source/Soviet_space_dogs) like [Laika](/source/Laika),[13] Belka,[14] Strelka,[15] Ugolyok,[16] and Veterok.[16]

## Phylogeny

In 2012, Adrain and McAdams said they believed that *Aponileus* was likely related to the "*Acidiphorus* group", but said that the [sister group](/source/Sister_group) remained unclear.[17] While *Psephosthenaspis* resembles *Aponileus*, Adrain and McAdams believe they belong to distinct [clades](/source/Clade).[9]

*Aponileus laikaae* is the [basal](/source/Basal_(phylogenetics)) species.[9]

## Distribution

Chronologically, *Aponileus* is found entirely within the [Lower Ordovician](/source/Lower_Ordovician), specifically the upper [Floian](/source/Floian) (Blackhillsian).[9] The genus's type species, *A. latus*, has found in the [El Paso Formation](/source/El_Paso_Formation) within the [Franklin Mountains](/source/Franklin_Mountains_(Texas)) of west Texas.[18] *A. glaber* was found in [Washington Land](/source/Washington_Land), in northwestern Greenland.[19] The remaining species, which Adrain and McAdams first described in 2012, are all from the [Confusion Range](/source/Confusion_Range) in [Millard County, Utah](/source/Millard_County,_Utah).[20]

## Species

As of 2021, the following species are recognized:[21]

- *[A. latus](/source/Aponileus_latus)* Hu, 1963 — Texas
- *[A. aasei](/source/Aponileus_aasei)* Adrain & McAdams, 2012 — Utah
- *[A. glaber](/source/Aponileus_glaber)* (Poulsen, 1927) — Greenland
- *[A. laikaae](/source/Aponileus_laikaae)* Adrain & McAdams, 2012 — Utah
- *[A. belkaae](/source/Aponileus_belkaae)* Adrain & McAdams, 2012 — Utah
- *[A. strelkaae](/source/Aponileus_strelkaae)* Adrain & McAdams, 2012 — Utah
- *[A. ugolekae](/source/Aponileus_ugolekae)* Adrain & McAdams, 2012— Utah
- [*A.*? *veterokae*](/source/Aponileus_latus) Adrain & McAdams, 2012 — Utah

## See also

- [2012 in arthropod paleontology § Trilobites](/source/2012_in_arthropod_paleontology#Trilobites)

## References

1. Hu 1963, pp. 87–88.

1. Fortey & Bruton 2013, p. 20.

1. Hu 1963, p. 87.

1. Adrain & McAdams 2012.

1. Adrain & McAdams 2012, p. 3.

1. Hintze 1952, pp. 137–138.

1. Hughes 1979, p. 154.

1. Jell & Adrain 2003, p. 343.

1. Adrain & McAdams 2012, p. 10.

1. Adrain & McAdams 2012, pp. 12–13.

1. McCobb et al. 2014, p. 583.

1. Adrain & McAdams 2012, p. 24.

1. Adrain & McAdams 2012, p. 13.

1. Adrain & McAdams 2012, p. 18.

1. Adrain & McAdams 2012, p. 20.

1. Adrain & McAdams 2012, p. 21.

1. Adrain & McAdams 2012, p. 6.

1. Adrain & McAdams 2012, p. 11.

1. Adrain & McAdams 2012, p. 12.

1. Adrain & McAdams 2012, pp. 11, 13, 18, 20–21.

### Works cited

- Adrain, Jonathan M. & McAdams, Neo E. B. (2012). "The Lower Ordovician (upper Floian) bathyurid trilobite *Aponileus* Hu, with species from Utah, Texas, and Greenland". *Zootaxa*. **3293**: 1–67. [doi:10.11646/zootaxa.3293.1.1](https://doi.org/10.11646/zootaxa.3293.1.1)
- Fortey, Richard A. & Bruton, David L. (2013). *Lower Ordovician Trilobites of the Kirtonryggen Formation, Spitsbergen*. Vol. 59. Fossils and Strata. Hoboken, New Jersey: Wiley-Blackwell. [doi:10.1002/9781118850657](https://doi.org/10.1002/9781118850657). ISBN 9781118825396.
- Hintze, Lehi F. (1952). [*Lower Ordovician Trilobites from Western Utah and Eastern Nevada*](https://ugspub.nr.utah.gov/publications/bulletins/b-48.pdf). Vol. 48. Utah Geological and Mineralogical Survey Bulletin. pp. 1–249.
- Hu, Chung-Hung (1963). ["Some Lower Ordovician Trilobites from Franklin Mountains,Texas"](https://www.jstage.jst.go.jp/article/prpsj1951/1963/51/1963_51_86/_pdf). *Transactions and Proceedings of the Palaeontological Society of Japan*. **51**: 86–90, pl. 13. New Series.
- Hughes, C. P. (1979). ["The Ordovician trilobite faunas of the Builth–Llandrindod Inlier, central Wales. Part III"](https://www.biodiversitylibrary.org/page/2277340). *Bulletin of the British Museum (Natural History)*. **32** (3): 109–181. Geology series.
- Jell, P.A. & Adrain, J.M. (2003). ["Available Generic Names for Trilobites"](https://www.biodiversitylibrary.org/page/52968715). *Memoirs of the Queensland Museum*. **48** (2): 331–553.
- McCobb, Lucy M.E.; Boyce, W. Douglas; Knight, Ian; Stouge, Svend (2014). "Lower Ordovician trilobites from the Septembersø formation, North-East Greenland". *Alcheringa: An Australasian Journal of Palaeontology*. **38** (4): 575–598. [Bibcode:2014Alch...38..575M](https://ui.adsabs.harvard.edu/abs/2014Alch...38..575M). [doi:10.1080/03115518.2014.951913](https://doi.org/10.1080/03115518.2014.951913). [S2CID 129962497](https://api.semanticscholar.org/CorpusID:129962497)

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Adapted from the Wikipedia article [Aponileus](https://en.wikipedia.org/wiki/Aponileus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Aponileus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.