Hollardops

{{Short description|Extinct genus of trilobites}}

{{Italic title}}

{{Taxobox

| fossil_range = {{fossil range|Emsian|Eifelian}}

| image = Hollardops mesocristata, Early Devonian, TazoulaOt Formation, Jbel OufatEne & Jbel Issoumour, MaOder Region, Morocco - Houston Museum of Natural Science - DSC01602.JPG

| image_caption = Hollardops sp.
Houston Museum of Natural Science - DSC01602

| regnum = Animalia

| phylum = Arthropoda

| classis = Trilobita

| ordo = Phacopida

| familia = Acastidae

| genus = Hollardops

| genus_authority = Morzadec, 1997

| subordo = Phacopina

| superfamilia = Acastoidea

| subfamilia = Asteropyginae

| subdivision_ranks = Species

| subdivision = {{specieslist

|Asteropyge mesocristata|Le Maître, 1952

|H. aithassainorum|Chatterton et al., 2006

|H. angustifrons|Van Viersen & Kloc, 2022

|Rhenops babini|Morzadec, 1983

|Philipsmithiana burtandmimiae|Lieberman & Kloc, 1997

|H. boudibensis|Morzadec, 2001

|Rhenops circumapodemus|Smeenk, 1983

|Philipsmithiana hyfinkeli|Lieberman & Kloc, 1997

|H. kyriarchos|Van Viersen & Kloc, 2022

|H. klugi|Van Viersen & Kloc, 2022

|H. luscus|Van Viersen & Kloc, 2022

|H. multatuli|Van Viersen & Kloc, 2022

|Greenops struvei|Morzadec, 1969

}}

}}

Hollardops is a genus of trilobite in the order Phacopida that lived during the Devonian. Their fossils are found in the upper Emsian of western Europe (France, Spain) and in the lower Emsian to lowermost Eifelian of North Africa (Morocco, Algeria). The type species, Asteropyge mesocristata, was described from Algeria by Le Maître in 1952. The genus Hollardops was erected by Morzadec in 1997.{{Cite journal |last=Morzadec |first=Pierre |date=1997-04-29 |title=Les Trilobites Asteropyginae du Dévonien de l'Ougarta (Algérie) |url=https://www.schweizerbart.de/papers/pala/detail/244/101033/Les_Trilobites_Asteropyginae_du_Devonien_de_l_Ouga?af=crossref |journal=Palaeontographica Abteilung A |volume=244 |issue=4–6 |language=fr |pages=143–158 |doi=10.1127/pala/244/1997/143|bibcode=1997PalAA.244..143M |s2cid=247209941 }} In the same year, Lieberman & Kloc{{Cite journal |last1=Lieberman |first1=Bruce S. |last2=Kloc |first2=Gerald J. |date=1997 |title=Evolutionary and biogeographic patterns in the Asteropyginae (Trilobita, Devonian) Delo, 1935 |url=https://digitallibrary.amnh.org/handle/2246/1623 |journal=Bulletin of the AMNH |language=en-US |volume= |issue=232}} erected Modellops and Philipsmithiana but those genera are regarded as subjective synonyms of Hollardops. The 10-segmented thoracic condition of Hollardops is a rare feature among acastid trilobites that almost always have 11 thorax segments. Van Viersen & Kloc (2022){{Cite journal |last1=Viersen |first1=Allart P. VAN |last2=J. Kloc |first2=Gerald |date=2022-12-09 |title=Functional morphology, coaptation and palaeoecology of Hollardops (Trilobita, Acastidae), with descriptions of new species and two new genera from the Devonian of Morocco |url=https://popups.uliege.be/1374-8505/index.php?id=7004 |journal=Geologica Belgica |volume=25 |issue=3–4 |pages=99–144 |language=en |doi=10.20341/gb.2022.005 |issn=1374-8505|doi-access=free }} revisited Hollardops and described a number of new species from the Devonian of Morocco. They also regarded Pennarbedops Bignon & Crônier, 2013 as a synonym of Hollardops. Van Viersen & Kloc construed Hollardops as a scavenger or predator with well-developed eyes, that used its shovel-like cephalon to plough the top layers of the sediment in search of food. Hollardops had small pits horizontally along the fringe of the exoskeleton; these are believed to have housed setae that allowed the trilobite to closely monitor its surroundings.