Phacopidae
Extinct family of trilobites
title: "Phacopidae" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["phacopidae", "phacopoidea", "trilobite-families", "late-ordovician-first-appearances", "late-devonian-animals", "late-devonian-extinctions"] description: "Extinct family of trilobites" topic_path: "general/phacopidae" source: "https://en.wikipedia.org/wiki/Phacopidae" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Extinct family of trilobites ::
| fossil_range = | image = Drotops armatus, Middle Devonian, Bou DOb Formation, Jbel Issoumour & Jbel Mrakib, MaOder Region, Morocco - Houston Museum of Natural Science - DSC01634.JPG | image_caption = Drotops armatus | display_parents = 2 | taxon = Phacopidae | authority = Hawle & Corda, 1847
Phacopidae is a family of phacopid trilobites that ranges from the Lower Ordovician to the Upper Devonian, with representatives in all paleocontinents.
Description
::figure[src="https://upload.wikimedia.org/wikipedia/commons/d/d5/Phacops_rana_crassituberculata_eye_2.jpg" caption="cephalon]]), a situation called micropygous."] ::
In the Phacopidae a merger of the anterior and the two pairs of neighbouring lobes of the glabella forms a frontal lobe that expands forward and can be inflated and overhanging the frontal border. To the back of the glabella two furrows (or sometimes one) cross the glabella forming two rings ("intercalating ring" and "occipital ring"). The cephalon does not end in genal spines. The side lobes of the thorax (or pleurae, singular pleura) have rounded ends. The pygidium is well rounded, semicircular or shorter, with an entire margin, and without lateral and posterior projections. In many Phacopidae, where the facial sutures are apparently continuous and well developed, they were evidently nonfunctional in ecdysis, since no separate free cheeks can be found.
Taxonomy
The Phacopinae likely have evolved from the Pterygometopidae, and the presumed sister taxon is Podowrinella.
Distribution
The earliest species and the only one known from the Ordovician (upper Katian) is Sambremeusaspis fossesensis. The Phacopidae became a prominent family during the Silurian and had an enormous taxonomic diversity during the Devonian.
Genera
The following genera are included:
- Acernaspis
- Acuticryphops
- Adastocephalum
- Afrops
- Ainasuella
- Altaesajania
- Ananaspis
- Angulophacops
- Arduennops
- Atopophacops
- Babinops
- Boeckops
- Burtonops
- Chotecops
- Cryphops
- Cultrops
- Denckmannites
- Dianops
- Dienstina
- Drotops
- Ductina
- Echidnops
- Echinophacops
- Eldredgeops
- Eocryphops
- Eophacops
- Geesops
- Hypsipariops
- Illaenula
- Kainops
- Liolophops
- Lochkovella
- Magreanops
- Morocops
- Nandanaspis
- Nephranomma
- Nephranops
- Nyterops
- Omegops
- Orygmatos
- Paciphacops
- Pedinopariops
- Phacopidella
- Phacops
- Plagiolaria
- Portlockia
- Prokops
- Rabienops
- Reedops
- Rhinophacops
- Rhinoreedops
- Sambremeusaspis
- Signatops
- Somatrikelon
- Spinicryphops
- Struveaspis
- Struveops
- Tangbailaspis
- Teichertops
- Toxophacops
- Trimerocephalus
- Viaphacops
- Weyerites
- Zaplaops
- Zhusilengops
References
References
- Moore, R.C.. (1959). "Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha". Geological Society of America/University of Kansas Press.
- J.M. Adrian. (2014). "Early Palaeozoic Biogeography and Palaeogeography". Geological Society of London.
- S.M. Gon III. "Order Phacopida".
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