|This is a nice trilobite plate with three Gerastos lisanrasus and one enrolled phacopid trilobite.|
The three Gerastos lisanrasus are shown nicely as a typical trilobite cluster.
Stacey Gibb 2005 mentions in here discussion of the new species the potential high affinity to Gerastos cultrijugati.
Maybe Gerastos lisanrasus build together with Gerastos cultrijugati and Gerastos doernbergensi a population group inside the genus Gerastos. This can might be called „Rhenocynproetus like Gerastos “ or „cultrijugatus Gerastos type“.
But it seems unlikely that this is a monophyletic species group regading the large distribution.
Gerastos cultrijugatus moved thew numerous taxa. Such as Longiproetus (Cavet & Pillet 1958), later it was assigned by Luetke 1990 to Devonoproetus. In 2002 Basse catched Gerastos cultrijugatus up in his new genus Rhenocynproetus. S. Gibb 2005 mention at the difficulty inside this species groub. Viersen and Prescher revising the genus Rhenocynproetus Basse 2002 as a junior synonym of Gerastos GOLDFUSS, 1843. Trilobites systematic isn’t easy. Especially above the species levis it is quite dynamic and sometimes it shows some relativity.
The Phacopid - Trilobite in this piece is might to account to the genus Geesops.
The matrix measures about 98 x 57 mm.
|Serdra near Tazzarine , Morocco|
|Size:||about 16, 17 & 18 mm long|
|Age:||Middle Devon, Eifilian (about 390 mill. y.o.)|