Mrirt area: Late Frasnian, Morocco

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Conodonta - Ozarkodinida - Palmatolepidae
Conodonta - Ozarkodinida - Polygnathidae
Polygnathus webbi Stauffer 1938
Trilobita - Proetida - Proetidae
Palpebralia sp. Richter and Richter 1927
Palpebralia brecciae (Richter 1913)
Trilobita - Proetida - Tropidocoryphidae
P. z. maroccanica subsp. nov.
    = Chlupaciparia maroccanica Feist 2002
Wagner 2020
Trilobita - Proetida - Otarionidae
Trilobita - Harpetida - Harpetidae
"Harpes" neogracilis Richter and Richter 1924
Trilobita - Phacopida - Phacopidae
Trilobita - Odontopleurida - Odontopleuridae
see common names

Geography
Country:Morocco
Coordinates: 33.2° North, 5.6° West (view map)
Paleocoordinates:39.0° South, 12.5° West (Wright 2013)
Basis of coordinate:based on political unit
Geographic resolution:local area
Time
Period: Devonian Epoch: Late Devonian
Stage: Frasnian 10 m.y. bin: Devonian 4
Key time interval: Late Frasnian Conodont zone:  upper Palmatolepis rhenana
Age range of interval: 375.2 - 372.15 m.y. ago
Stratigraphy
Formation:Bou Nebedou Member:Mrirt
Stratigraphic resolution:group of beds
Stratigraphy comments: Late Devonian cephalopod limestones in olistolithic slabs contained within Visean shales. Collections come from between the Lower and Upper Kellwasser events. Late Palmatolepis rhenana Zone.
Lithology and environment
Primary lithology:gray lime mudstone
Includes fossils?Y
Lithology description: "In this area the latest Frasnian succession is characterized by the occurrence of two dark-grey hypoxic limestone levels of Kellwasser-Kalk facies, the Lower (LKW) and Upper (UKW) Kellwasser levels (Lazreq 1992). They are separated by 80 cm of intervening grey-beige oxic calcilutites assigned to the Late Palmatolepis rhenana Zone by Lazreq (1992, 1999). The trilobites were recovered in section “1” from two levels: the older is situated 13 cm above theLKW, the younger 18 cm below the base of the UKW (horizons “1A” and “1B” in Fig. 1B). The sample collected in section “2” corresponds to the younger fauna of section “1”. Associated conodonts recov- ered from matrix material of the trilobite-bearing rocks were determined by Catherine Girard and Gilbert Klapper as fol- lows: the lower trilobite horizon yields Palmatolepis hassi sensu stricto and Pa. bogartensis which indicates the lower part ofMNZone 13 (for correlation of conodont zonations, see Klapper and Becker 1999); the upper trilobite bearing horizon yields Pa. rhenana, Pa. boogaardi, abundant Pa. bogartensis, Ancyrognathus asymmetricus and Polygnathus webbi (but neither Pa. linguiformis nor An. ubiquitus were found), indi- cating correlation with the upper part of MN Zone 13. Trilobite debris of exclusively disarticulated exuviae is concentrated in thin layers within the biomicritic limestone, along with mass occurrences of conodonts, homoctenid tenta- culites and fewer manticoceratid goniatites, smooth brachio- pods and crinoid ossicles. The association of reduced-eyed and blind trilobites with predominantly necto-benthonic organ- isms characterizes the well oxygenated cephalopod realm of a moderately deep outer platform environment. Accumulations of shelly debris that do not exhibit any evidence of corrosion and size sorting might result from intermittently slow sedi- mentation rates rather than from physical transport.
Environment:platform/shelf-margin reef
Geology comments: The association of reduced-eyed and blind trilobites with predominantly necto-benthonic organisms characterizes the well oxygenated cephalopod realm of a moderately deep outer platform environment. Accumulations of shelly debris that do not exhibit any evidence of corrosion and size sorting might result from intermittently slow sedimentation rates rather than from physical transport.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils,mesofossils
Collection methods and comments
Collection excludes:some macrofossils
Reason for describing collection:biostratigraphic analysis
Taxonomic list comments:Only trilobites and conodonts listed. Also present are tentaculites, cephalopods, brachiopods, and crinoid ossicles.

This can be split into individual horizons: PJW 2014-07-14.
Metadata
Also known as:Trilobites between Lower and Upper Kellwasser events, Mrirt area, Morocco
Database number:35385
Authorizer:M. Foote, P. Wagner Enterer:M. Foote, P. Wagner
Modifier:P. Wagner Research group:marine invertebrate
Created:2003-12-09 11:04:07 Last modified:2025-02-22 15:12:02
Access level:the public Released:2003-12-09 11:04:07
Creative Commons license:CC0
Reference information

Primary reference:
9563. R. Feist. 2002. Trilobites from the latest Frasnian Kellwasser Crisis in North Africa (Mrirt, central Moroccan Meseta). Acta Palaeontologica Polonica 47(2):203-210 [M. Foote/M. Foote/M. Foote]

Secondary references:

75124 R. Feist. 2003. Biostratigraphy of Devonian tropidocoryphid trilobites from the Montagne Noire (southern France). Bulletin of Geosciences 78(4):431-446 [P. Wagner/P. Wagner]
65064 P. Wagner. 2020. Subspecies kluges: a pointless taxonomic database to create species opinions for subspecies that then will be over-ruled and allow subspecies occurrences to be recognized as the subspecies rather than the parent species. [P. Wagner/P. Wagner/P. Wagner]