Russian Asaphus Trilobite Evolutionary Sequence:

Selective pressures due to salinity and turbidity led to adaptations of Asaphus genus Russian Ordovician Trilobites (see figure below). Asaphus expansus branched into two Asaphidae lines of decent, one ultimately leading to Asaphus kowalewski with high eyestalks, and the other branching into two lines, one leading to Asaphus plautini with its large, sharp genal spines genal, and the other leading to another sequence of ever higher eye stalks in Asaphus kotlukovi, then Asaphus punctatus, followed by Asaphus intermedius and finally Asaphus convincens. These observed evolutionary trends are supported by a century of cladistics research that document about two million years of adaptive radiation within the Asery horizon that is more than 50 feet think. As with the examples above, lines of descent can be traced from the ancestors on lower horizons (Wolchow and Kundra), to descendants in the upper horizons (Lasnamjagi and Llandeilo), as shown in the figure below (you can follow some hot spots in the figure).

Return to: Russian Trilobites










Russian Asaphus Trilobite Evolutionary Sequence Asaphus expansus Asaphus kowalewskii Asaphus delphinus Asaphus raniceps Russian Trilobite Asaphus lepidurus Asaphus kotlukovi Russian Trilobites Asaphus punctatus High-Eyestalked Russian Trilobite Asaphus latus

List of Asaphus trilobites:
Asaphus applananatus
Asaphus broggeri
Asaphus convincens
Asaphus cornutus
Asaphus delphinus
Asaphus holmi
Asaphus insolensus
Asaphus internedius
Asaphus kotlukovi
Asaphus kowalewskii
Asaphus knyrkoi
Asaphus laevissimus
Asaphus laticaudus
Asaphus lepidurus
Asaphus lamanskii
Asaphus major
Asaphus minor
Asaphus ornatus
Asaphus nodiurus
Asaphus pachyophthalmus
Asaphus platyurus
Asaphus plautini
Asaphas popovi
Asaphus punctatus
Asaphus raniceps
Asaphus ultimus