Minicryphaeus

Order:  PHACOPIDA  Salter, 1864

Suborder: PHACOPINA  Struve, 1959

Superfamily: ACASTOIDEA  Reijers, 1972

Family: ACASTIDAE  Delo, 1935

Subfamily: ASTEROPYGINAE  Delo, 1935

Genus MINICRYPHAEUS  Bignon and Crônier, 2014

 

Diagnosis

Diagnosis (emend. from Bignon and Crônier, 2014):

Cephalon may have a prefrontal spine; frontal lobe diamond shaped; axial furrows straight between S1 and S3, no contact between S2 and axial furrows; 5–8 lenses per vertical row on visual surface; genal spine shorter than glabella with narrow proximal portion; narrow anterior border, lateral border very large, poorly or developed on genal spine.

Pygidium with anterior pleural bands as wide and elevated as posterior bands, flat pleural bands; axis with 7–10 rings; 4 or 5 pleural segments; 4 or 5 pairs of pygidial spines shorter than pleural width (tr.), mainly developed from posterior pleural bands; terminal pygidial spine wider than axis, roughly triangular, twice or as long as other pygidial spines.

 

Occurence

Minicryphaeus is found in the Pragian (Lower Devonian) of the Mader Basin, in Morocco

 

Recognizing Minicryphaeus species

Morzadec described the first 3 species in 2001. He assigned them to the genus Pseudocryphaeus. Bignon and Crônier (2014) determined them to be a distinct genus, Minicryphaeus. In Morocco this genus is often referred to as ‘Cryphina’. Pseudocryphaeus does not exist in Morocco.

 


 

Minicryphaeus minimus

Morzadec 2001 (Pragian)

There is a long median spine in front of the cephalon. The eyes have 21 rows of maximum 5 lenses. The occicpital ring bares a median tubercle.

The pygidium has 5 pairs of pygidial spines. The median spine is longer than the rest.


 

Minicryphaeus quaterspinosus

Morzadec 2001 (Pragian)

The cephalon enlarges a lot around the eyes with a flat limb extended towards the front by a spine. The genal spines are short and steamlined. The eyes have 22 rows of maximum 6 lenses.

The pygidium has only 4 pairs of pointed pygidial spines. The median spine is broad at the base and is longer than the lateral pygidial spines.


minicryphaeus sarius

Minicryphaeus sarius

Morzadec 2001 (Pragian)

Cephalon: M. sarius has very large cheeks. The genal spines are short and streamlined. The eyes have 24 rows of maximum 8 lenses. The occipital ring is smooth.

The pygidium has 5 pairs of pygidial spines that are quite long, acute and clearly spaced. The median spine is  triangular and is much longer than the other pygidial spines.

 

Picture used with permission of Sam Gon III


minicryphaeus giganteusMinicryphaeus giganteus

Minicryphaeus giganteus

Bignon and Crônier, 2014 (Pragian)

This species is very easy to recognize because of its size. It is almost 3 times larges than the other species (7-8,5 cm)

Cephalon:
The cephalon has a precephalic spine, but it has a thinner basis as M. minimus. The eyes have 34 rows of maximum 8 lenses.

Pygidium:
The pygidium has a median spine that is as long as the other pygidial spines.

 

Image used with permission (Bignon & al, 2014)
Picture used with permission of Luis Gopaldas


 

References

Bignon, A., Crônier, C., 2014. The systematics and phylogeny of the Devonian subfamily Asteropyginae (Trilobita: Phacopida). Journal of Systematic Palaeontology 12, 637–668.

Morzadec, P., 2001. Les trilobites Asteropyginae du Dévonien de l’Anti-Atlas (Maroc). Palaeontographica Abteilung A 262, 53–85.