Comura bultyncki

Comura bultyncki MORZADEC 2001

Comura bultyncki MORZADEC 2001 is a Moroccan Devonian asteropygine.

Here a splendid complete specimen of one of the most spectacular species of trilobites known as “spiny,” quite simply because their spines are hyper-developed. For the collectors of asteropygines, as well as collectors of Moroccan trilobites, Comura bultyncki is a kind of a grail. There is little doubt of the species when you find one of them. On the other hand, beware of the fakes on the Net!

2001

Comura bultyncki

nov. sp., MORZADEC 2001, p.69, plate12, fig. 1 - 4.

Specimen description :

Complete trilobite.
On matrix.
Almost perfectly symetrical
Total size : 57 mm including the pygidial spines.
Devonian.
El Otfal Formation, Upper Emsian.
Ma'der.
Morroco.

Antero-lateral view of the specimen.

Postero-lateral view.

Diagnosis :

Order	Phacopida	SALTER 1864	Occurrence: Lower Ordovician (Tremadoc) to Upper Devonian (Famennian). Cephalon: Proparian (Phacopina and Cheirurina), gonatoparian (Calymenina) or opisthoparian (Calymenina), Preglabellar field often very short or absent. 4 or fewer pairs of glabellar furrows. Eyes : when present, schizochroal (Phacopina) or holochroal (Cheirurina and Calymenina). With rostral plates (Calymenina and Cheirurina) or without (some Phacopina). Hypostome conterminant (all suborders) to impendent (some devonian Phacopina). Exosqueletton generally granulous. Thorax: 8 – 19 segments, sometimes distinctly furrowed. Axis sometimes broad (e.g., Homalonotidae). Pygidium : Typically micropygous (most Calymenina and Phacopina), but variable (e.g., subisopygous in Dalmanitoidea and Acastoidea). May be lobed or spiny (e.g., Cheirurina, some Dalmanitoidea, Acastoidea), or smooth-margined, with round or subtriangular outline (e.g., Calymenina, Phacopoidea).
Sub-order	Phacopina	STRUVE 1959	Cephalon : Proparian sutures (sometimes fused). Schizochroal eyes. Glabella expands forwards. Librigena typically yoked as single piece. Hypostome conterminant to impendent, some with no rostral plate. Some with genal spines. Thorax: 10 to (typically) 11 segments. Pleurae furrowed, articulating facets distinct. Rounded, angular, or spinose tips. Pygidium : Typically smaller than cephalon (but subisopygous in Dalmanitoidea and Acastoidea). Smooth or spinose.
Super-family	Acastoiedea	DELO 1935	Cephalon : Axial furrows slightly to moderately divergent. Anterior glabellar lobes and furrows usually not fused (although furrows may be indistinct). Eyes typically distant from posterior border furrows, but not strongly anterior. Frontal glabellar lobe auxilliary impression system triangular in outline. Maximum width of glabella adjacent to preglabellar furrow. Median region of glabella devoid of muscle scars. Cephalic margin "shouldered". Laterally convex course of genal margin topographically distinct from curvature of axial margin. Thorax : Pleural endings blunt, rounded or angular. Sometimes spinose. Pygidium : Micropygous to subisopygous. Sometimes spinose (expressed as marginal spines). Pygidial axis with deep, apodemal anterior ring furrows, with abrupt transition to shallow posterior ring furrows. Coincident decrease in angle of axial furrow convergence.
Family	Acastidae	EDGECOMBE 1993	Cephalon : Semi-circular to rounded subtriangular. Cephalic border narrow in front of the glabella. Dorsal furrows slilghtly to moderately divergent. Anterior glabellar furrows (S3) simple. Medial furrows (S2) moderately deep. Deep posterior furrows (S1). L2 and L3 lateral glabellar lobes generally fused distally. Muscle scars bearing sometimes callosities (Acastinae). Eyes typically distant from the posterior genal furrows. Hypostoma Pygidium : micropygous to subisopygous. Semi-circular to rounded subtriangular. Short posterior spine present.
Sub-family	Asteropyginae	DELO 1935	Traditionnally included in the Dalmanitidae, Asteropyginae are now included in the Acastids. Mostly benthic trilobites. Cephalon : Closely similar to the Dalamanatid Dalmanitides BARRANDE 1853. Glabella expanding forward. 3 lateral glabellar furrows. Eyes generally large. Genal angles acutely pointed or bearing medium-length to very long genal spines in straight continuation of lateral margins. Pygidium : Rachis never reaching the posterior region of the pygidial border. Generally 5 pairs of lateral spines (sometimes 4 or 6). Unpaired posterior lappet or spine.
Genus	*Comura*	R. & E. RICHTER 1926
Species	*bultyncki*	MORZADEC 2001	Cephalon : trapezoïdal strip/tongue in front of the cephalon. Long occipital spine Palpebral and metaxigenal spines 30 dorso-ventral files of with a maximum of 11 lenses per file. Thorax : First thoracic ring without median spine on the rachis. Pygidium : 10 curved/bent axial rings. 5 pairs of pleural ribs, the 5 anterior pairs bearing in their distal part a pair of dorso-ventral spines. 5 pairs of lateral pygidial spines, whose 5th pair does not exceed subsequently the level of 4th. Median spine moderatly shorter than the 5th lateral spines.

Complementary description :

Cephalon :
In front of the cephalon, the limb widens in a strip of trapezoidal contour.
The occipital ring carries a long median spine bent backwards whose end reaches the level of the 5th thoracic ring.
The palpebral lobes present each one a bent spine.
On the posterior edge of the cephalon, a pair of metafixigenal spines.
The L3 lobes and the frontal lobe of glabella decorated with large tubercles.
Visual areas made up of 30 dorso-ventral files with a maximum of 12 lenses per file.
The genal points are short, reaching the level of the 4th thoracic segment.
Thorax :
11 segments which all carry, except the first, a long median spine of which the length decreases towards the back and a vertical spine at the pleural ends.
The pleurae are prolonged by long pleural spines.
Pygidium : 10 axial rings with on each one a long bent median spine.
5 - 6 pairs of pleural ribs, 5th and the 6th being reduced to has half-ribs, separated by broad pleural furrows.
The former half-ribs are broader and more in relief that the posterior ones and present each one a vertical spine towards their distal end.
The pygidial segmentation is of cometa type.
The 5 pairs of pygidial spines are fine/thin, of sub-circular section and bent backwards.
The 4 first are of the same length, the shorter 5th does not exceed in length the 4th.
The median spine is slightly shorter than the fifth pair of lateral spines.

More pictures :

Antero-lateral view, B&W.


Lef lateral view. Note the lack of chemical treatment on the first hemi-thoracic segments.	Frontal view of the cephalon.


Details of the thoracic and pygidial spines	Details of the palpebral and metafixigenal spines.

Study of the thoracic spines. No spine on the first segment.

References :

MORZADEC P. 2001. Les Trilobites Asteropyginae du Dévonien de l'Anti-Atlas (Maroc) [Asteropyginae Trilobites from the Devonian of the Anti-Atlas (Morocco)]. Paleontograph. Abt. A 262 (1/3) : pp 53 - 85.

Back to Home Page