Challenging Darwin: Evolution of Triassic Conodonts and Their Struggle for Life in a Changing World

Abstract The phylogeny and distribution of Triassic conodonts reveal many aspects of their natural history. Conodonts incorporate the morphologic response to temperature as well as to eustatic cycles. Speciation, radiation, and extinction are not fortuitous and evolution uses heterochrony (progenesis and neoteny) in response to stress-generating events. Proteromorphosis (reappearance of ancestral morphs) and paedomorphosis (retention of juvenile traits) is a reaction to sublethal environmental stress. This often follows radiation of fully developed forms in the recovery stage after extinction that timely matches transgressions. Evolutionary retrogradation (neoteny) during eustatic high stan…

Conodonts versus Triassic Climatic and Eustatic Changes

Kılıç, Ali Murat (Balikesir Author)

Évolution rétrograde de Neospathodus au cours de la crise Permo - Triasique

The Permian - Triassic evolution of platform conodonts (Gondolellidae) consists mainly in developing the carina and the platform. During the sublethal environmental stress conditions subsequent to the Permian - Triassic extinction, the Wuchiapingian - Griesbachian Clarkina lineage is replaced by the primitive looking platform-lacking Dienerian - Aegean Neospathodus kummeli - Kashmirella timorensis lineage. Moreover, above Jinogondolella denticulata, end of the Capitanian Jinogondolella lineage, “Neospathodus” arcucristatus, an atavistic blade-like homeomorph that lacks a platform, underlies Protoclarkina crofti, of the base of the anagenetic Clarkina lineage. These primitive-looking forms a…

The evolutionary trend of platform denticulation in Middle Triassic acuminate Gondolellidae (Conodonta)

Kılıç, Ali Murat (Balikesir Author)

On the ontogeny and orientation of the Triassic Conodont P1-element in Pseudofurnishius murcianus Van den Boogaard, 1966

Successive growth stages of P1-elements in the Middle to early Late Triassic species Pseudofurnishius murcianus allows the observation of a detailed ontogeny. Besides the gradual enlargement of its curved blade and the growing number of its denticles, a small internal platform develops, eventually followed by an external one, both bearing denticles. The number of denticles on the blade and internal platform increases from five and one in the smallest specimens, respectively, to 14 and 9 in fully developed ones, whereby the distribution pattern of platform-denticles, on the inner one in particular, is of great morphological variety. For the orientation of the P1-element of P. murcianus, the …

Taxonomy and evolution of the Triassic conodont Pseudofurnishius

Pseudofurnishius is a late Anisian (Pelsonian)—early Carnian (Cordevolian) conodont genus of gondolellid stock, characteristic for the Sephardic Province and restricted to the “Southern Tethys” region of the northern margin of Gondwana. Its most commonly found species, Pseudofurnishius murcianus, appears at the base of the Ladinian (Fassanian). The Ladinian material of Spain reveals its ontogeny characterised by initial lateral protrusions from the carina that may develop first mono-platform and later bi-platform units, finally evolving into elaborated multi-denticulated forms. The late Anisian—early Carnian phylogenesis of Pseudofurnishius priscus → P. shagami → P. murcianus is proposed. A…

Comments on: A review of the evolution, biostratigraphy, provincialism and diversity of Middle and early Late Triassic conodonts