Late Ordovician and Early Silurian graptolites from southern Iran

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Graptolites are described for the first time from the Faraghun mountains (Kuh-e-Faraghun) and the Gahkum mountains (Kuh-e-Gahkum) on the northern edge of the southeast part of the Zagros Mountains, Iran. 38 taxa are recorded, including 4 Ordovician and 34 Silurian species; the latter are the first Silurian graptolites described from Iran.

Ashgill (Late Ordovician) graptolite assemblages from Kuh-e-Faraghun include: Persculptograptus persculptus and Orthograptus amplexicaulis, indicating a persculptus Biozone age; and Orthograptus amplexicaulis abbreviatus, indicating the latest Ordovician anceps Biozone.

Kuh-e-Faraghun Early Silurian faunas include representatives of the Llandovery leptotheca Biozone; another assemblage, including Monograptus convolutus and Pseudorthograptus inopinatus, indicates the slightly younger Llandovery convolutus Biozone. Graptolites from Kuh-e-Gahkum comprise a rich Stimulograptus sedgwickii assemblage, indicating a slightly higher Llandovery level again (sedgwickii Biozone); a convolutus Biozone fauna is also probably represented in our collections.