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Our Trilobites of the Order Phacopida

 


Metacanthina barrandei (I)

 

 

Survey of images

Metacanthina barrandei (I_01).. (I_08)

 

General Informations

Locality

Formation

 

 Southern Morocco, Atlas Mountains, Alnif/ Fezzou

 Laatchana Formation

Stratigraphy

 

 Middle Devonian

Age

 ca. 380 Mio. Years
Taxon  Order Phacopida\ Suborder Phacopina\ Superfamily Acastoidea

 

.

Metacanthina barrandei (I_01)

 

 

 

Morphological features

I. Sizes [in.]
Cephalon  

 

Length:

  Total length, 

  Cephalic length:

 

Diameter Lateral margin:

Glabella:

 

 

The Cephalons total length  Anterior margin, Genal spine is 1,14 whereupon the length  Anterior margin, Occipital lobe (posterior) represents 0,63.

 

The maximum Diameter is 1,30.

The Glabellas length is 0,50 whereupon the maximum width is 0,61.

Thorax  

 

Thoracic- length and width:

Max. elevation rachis:

 

The thoracic length amounts to 1,16 at maximum width of 1,34.

The maximum visible elevation is 0,07 (Pleura, Max.).

Pygidium  

 

Length:

 

The length along the central axis amounts to 0,55 (pygidial spine incl.).

 

 

II. Structures
Cephalon  

 

Glabella anterior divergent, ranging to the anterior border; 3 pairs of glabellar furrows visible; schizochroal eyes (lenses partial missing at left eye); Librigenae developed prominently; prominent eye ridges and palpebrae; posterior forrow prominent; sutures proparian articulated (particulary right side); Genal spines prepped free like needle laces, with genal furrow adumbrated.

Thorax  

 

11 thoracic segments; prominent pleural furrows.

Pygidium  
 

Pygidial border is ending in broad pygidial spines; prominent border furrow; segments affiliated.

 

 

 

Conclusion

Cause of fracture (the segment before last, posterior), the thorax is slightly embedded in torsive way (I_03, I_08), but completely preserved. Some lenses are missing at the left eye, the preserved lenses are very well prepped free. This trilobite is a typical representative of the Species Metacanthina barrandei morphologically.

 


Zlichovaspis sp. (I)

 

 

Survey of images

Zlichovaspis sp. (I_01).. (I_06)

 

General Informations

Locality

Formation

 

 Southern Morocco, Atlas Mountains, Alnif/ Fezzou

 Laatchana Formation

Stratigraphy

 

 Middle Devonian

Age

 ca. 380 Mio. Years
Taxon  Order Phacopida\ Suborder Phacopina\ Superfamily Dalmanitoidea

 

.

Zlichovaspis sp. (I_01)

 

 

Morphological features

I. Sizes [in.]
Cephalon  

 

Length:

  Total length, 

  Cephalic length:

 

Diameter Lateral margin:

Glabella:

Preglabellar field:

 

Anterior border:

 

 

The Cephalons total length  Anterior margin, Genal spine is 1,61 whereupon the length  Anterior margin, Occipital lobe (posterior) represents 0,76.

 

The maximum Diameter is 1,44.

The Glabellas length is 0,55 whereupon the maximum width is 0,56.

The field's witdth anterior of the glabella is 0,02.

 

The border's width is 0,079 (axial).

 

Thorax  

 

Thoracic- length and width:

Max. elevation rachis:

 

The thoracic length amounts to 0,97 at maximum width of 1,22.

The maximum visible elevation is 0,063 (Pleura, Max.).

Pygidium  

 

Length:

 

The length along the central axis amounts to 0,72 (pygidial spine incl.).

 

 

II. Structures
Cephalon  

 

Glabella anterior divergent, articulate convex; small- sized preglabellar field; anterior border with axial bulge; 3 pairs of glabellar furrows; big- sized schizochroal eyes (semilunar, horizontal circumferential visibility); librigenae well articulated; eye furrow and palprebal lobe well articulated; posterior border articulated; occipital ring with occipital knot; sutures proparian articulated; long genal spines with genal furrows adumbrated.

 

Thorax  

 

11 thoracic segments; prominent pleural furrows.

Pygidium  
 

Articulated pygidial border, axial with little aceterated spine; prominent border furrow; segments affiliated; dorsal furrow present.

 

 

 

 

Conclusion

Even the pygidium is slightly dislocated, this is a Odontochile in very well preservation. Every characteristic feature of this Species is present at this representative.

 


Calymene celebra (I)

 

 

Survey of images

Calymene celebra (I_01).. (I_06)

 

General Informationens

Locality

Formation

 

USA, Ohio, Ludlow Falls

Cedarville Dolomit

Stratigraphy

 

Silur (Llandovery)

Age

ca. 430 Mio. Years
Taxon Order Phacopida\ Suborder Calymenina\ Family Calymene

 

.

Calymene celebra (I_01)

 

Diskussion

With this "big caterpillar" only the mineral Dolomit, formerly covered with trilobites exoskeleton, remained over the process of fossilisation from the exoskeletons leading layer. This well- defined Calymene has a total length of 43,8mm.

 

Cephalon triangular shaped with max. width of 28,2mm and a total length of 11,0mm; short preglabellar field; sutures ending at genal angles (gonatoparian); glabella tapering forwards; S0 occipital furrow as well as 3 lateral furrows (S1..S3); knobby lateral lobes L1, L2; very small holochroal eyes.

 

Thorax with total length of 32,0mm and a max. width of 21,5mm; 13 thoracic segments; rachis significantly vaulted ; defined dorsal furrows; pleures also vaulted with well defined pleural furrows; ribbons well developed;

 

Pygidium with a total length of 8mm, triangular; rachis ring vaulted with furrow.


Placoparia zippei (I)

 

 

Survey of images

Placoparia zippei (I_01).. (I_10)

 

General Informations

Locality

Formation

 

Rokycany, Czech Republic

Sarka Formation

Stratigraphy

 

Lower Ordovician

Age

ca. 475 Mio. Years
Taxon Order Phacopida\ Suborder Cheirurina\ Superfamily Pliomeridae

 

.

Placoparia zippei (I_01)

 

 

Discussion

A nearly complete positive fossil, as well as it's  complete negative cast's hidden inside of this concretion. The sectional plane is exactly trilobites frontal layer. Trilobites total length is 29,0mm. The exoskeleton is defined sharply.

 

Cephalons shape is a circular segment with 6,3mm in height and a maximum width of 13,4mm; anterior border with small fringe (I_07,08), sharply defined posterior border with posterior furrow; rectangular glabella, slightly trapezoidal widening forward; no preglabellar field;  3 pairs of sharply incised lateral glabellar furrows; sharply defined intraocular fixigenae; no eyes; pointed genal angle.

 

Thorax with anterior maximum with  of 13,1mm, posterior tapering; 12 segments; Rachis vaulted intesively (I_09); pleures dorsal orthodromic and strongly orthogonal towards rachis; inflated pleures sloping distally.

 

Very small pygidium with broad spines (I_10), also sloping distally.



 

 
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