Trilobite - Crotalocephalus sp.
SKU:
ITEM # TRILO-Morocco-0029
$250.00
$250.00
Devonian - 360 mya
Anlif, Morocco
ITEM # TRILO-Morocco-0029
This is an excellent example of a trilobite Crotalocephalus sp. from the Devonian of Morocco. Crotalocephalus sp. is a member of the Order Phacopida, Family Cheiruridae.
The most diagnostic features of this taxon are the sharp pleural and pygidial spines and the distinctive cephalon. The describer of this one thought it bore a resemblance to the head of a rattlesnake (Crotalus), hence the genus name. The spines may have aided it in staying at the surface of the soft seafloor. This one is displayed in a sinuous pose as if undulating across its matrix. The name has changed several times, from Crotalocephalus to Crotalocephalina, and recently to Cheirurus, making it hard for the layman to keep up.
Phacopida ("lens-face") is an order of trilobite that lived from the Ordivician to the Devonian. It is made up of a morphologically diverse group of related suborders.
The origin of the Phacopida order is uncertain. It comprises three suborders (Phacopina, Calymenina, and Cheirurina), which share a distinctive protaspis (developmental stage lacking segments) type. The Cheirurina and Calymenina retain a rostral plate (an apomorphy) but in virtually all Phacopina the free cheeks are yoked as a single piece.
This sort of similarity in development suggest phylogenetic unity. The suborder Calymenina is the most primitive of the Phacopida order and shares some characteristics with the order Ptychopariida, though it is not included in the subclass Libristoma.
Phacopida had 8 to 19 thoracic segments and are distinguishable by the expanded glabella, short or absent preglabellar area, and schizochroal (Phacopina) or holochroal (Cheirurina and Calymenina) eyes. Schizochroal eyes are compound eyes with up to around 700 separate lenses. Each lens has an individual cornea which extended into a rather large sclera. The development of schizochroal eyes in phacopid trilobites is an example of post-displacement paedomorphosis. The eyes of immature holchroal Cambrian trilobites were basically miniature schizochroal eyes. In Phacopida, these were retained, via delayed growth of these immature structures (post-displacement), into the adult form.
This specimen is approximately 3 3/4 inches long on a matrix measuring 3 3/4 inches by 5 1/4 inches.
SORRY, THIS ITEM IS SOLD.
Anlif, Morocco
ITEM # TRILO-Morocco-0029
This is an excellent example of a trilobite Crotalocephalus sp. from the Devonian of Morocco. Crotalocephalus sp. is a member of the Order Phacopida, Family Cheiruridae.
The most diagnostic features of this taxon are the sharp pleural and pygidial spines and the distinctive cephalon. The describer of this one thought it bore a resemblance to the head of a rattlesnake (Crotalus), hence the genus name. The spines may have aided it in staying at the surface of the soft seafloor. This one is displayed in a sinuous pose as if undulating across its matrix. The name has changed several times, from Crotalocephalus to Crotalocephalina, and recently to Cheirurus, making it hard for the layman to keep up.
Phacopida ("lens-face") is an order of trilobite that lived from the Ordivician to the Devonian. It is made up of a morphologically diverse group of related suborders.
The origin of the Phacopida order is uncertain. It comprises three suborders (Phacopina, Calymenina, and Cheirurina), which share a distinctive protaspis (developmental stage lacking segments) type. The Cheirurina and Calymenina retain a rostral plate (an apomorphy) but in virtually all Phacopina the free cheeks are yoked as a single piece.
This sort of similarity in development suggest phylogenetic unity. The suborder Calymenina is the most primitive of the Phacopida order and shares some characteristics with the order Ptychopariida, though it is not included in the subclass Libristoma.
Phacopida had 8 to 19 thoracic segments and are distinguishable by the expanded glabella, short or absent preglabellar area, and schizochroal (Phacopina) or holochroal (Cheirurina and Calymenina) eyes. Schizochroal eyes are compound eyes with up to around 700 separate lenses. Each lens has an individual cornea which extended into a rather large sclera. The development of schizochroal eyes in phacopid trilobites is an example of post-displacement paedomorphosis. The eyes of immature holchroal Cambrian trilobites were basically miniature schizochroal eyes. In Phacopida, these were retained, via delayed growth of these immature structures (post-displacement), into the adult form.
This specimen is approximately 3 3/4 inches long on a matrix measuring 3 3/4 inches by 5 1/4 inches.
SORRY, THIS ITEM IS SOLD.
