• Almost complete, prone on matrix
• Part of anterior border of the cephalon missing as of the last thoracic ring.
• Exoskeleton hardly granulous.
• Ordovician.
• Valongo, Portugal.
• Size : 72 mm.

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).

• Cephalon: Semicircular to subtriangular.
• Typically with gonatoparian sutures (a few opisthoparian, e.g., Bathycheilidae, primitive Homalonotidae).
• Glabella narrowing forwards.
• Eyes holochroal, often small.
• Hypostome conterminant.
• Rostral plate present.
• Thorax: 11 – 13 (typically 13) segments with rounded tips.
• Pygidium: Semicircular or triangular.
• Without spinose margin.

Family

Calymenidæ

BURMEISTER 1843

• Cephalon : Semicircular and convex.
• Glabella bell-shaped or parabolic
• Glabella widest across occipital ring or preoccipital.
• May or may not project in front of genae.
• 2 to 4 pairs of lateral furrows.
• Lateral lobes of glabella diminishing in size forward, tending to be isolated by shallow furrows from median lobe and independantly convex (2nd and 3rd lateral lobes - L2 and L3 - may be papillate).
• Axial furrows bordering lateral glabellar lobes deep.
• Anterior pit deep.
• Relatively small eye lobes, situated on the highest part of genae opposite to L2 or L3.
• Low eye ridges may be present.
• Convex lateral border clearly defined by broad furrows.
• Frontal area variable in length (sag.), in some form extending into frontal spine.
• Connective sutures converging backwards.
• Doublure rolled under borders and not extending inside them.
• Hypostoma longer than wide, with subovate middle body.
• Posterior lobe of the hypostoma crescentic.
• Large anterior hypostomal wings.
• Thorax : 12 ou 13 segments.
• Axis convex .
• Deep articulating furrows and apodemal pits.
• Pygidium : Axis extending almost to posterior margin.
• Axis sloping steeply backward and sideward.

Subfamily

HUPÉ 1855

• Cephalon : Semicircular to semielliptical, much wider than long.
• Border defined in front only, very narrow, touching front of glabella. in anterior view, strongly bent down at sides.
• Glabella narrowing forward considerably, with smoothly convex sides, anterior end truncate.
• Circumglabellar furrows sharp and rather deep.
• 2 - 4 pairs of lateral glabellar furrows.
• Eyes usually far forward.
• Eye lobes strinkingly small, not elevated above genæ, hardly interrupting general course of facial sutures.
• Weak eye ridges may be present.
• Fixigenæ very wide (tr.)
• Posterior sections of facial sutures forming evenly convex curves that cut margins of cephalon near genal angles.
• Rostral suture apparently on anterior margin.
• Thorax : Well-marked moderately wide axis.
• Pygidium : Transversely elliptical or subtriangular, wider than long.
• Trilobation distinct.

Genus

Salterocoryphe

HAMMANN 1977

• Cephalon : Glabella pentagonal.
• Dorsal furrows converging forward
• 3 or 4 pairs of lateral furrows
• Preglabellar area short (sag.) and convex, well delimited with the glabella by a deep furrow.
• Pygidium : Coaptativ structures more or less developped.
• External pleural field with visible segmentation.

Species

salteri

(ROUAULT 1851)

• Cephalon : Glabella narrow (tr.) with slightly concave side edges towards outside. The reduction in width is more notable in the anterior part.
• Convex preglabellar area.
• Stalk eyes, whose posterior ends are on the level of S2.
• Pygidium : Rachis narrow (tr.), well segmented.
• 10 à 11 axial rings.
• Pleurae divided into 2 by a furrow (coaptative structure).
• 7 to 8 furrows perpendicular to the pygidial border on the external portions of the pleurae.
• With the exception of the furrows and articular surfaces, granulations covering the whole of the exoskeleton.

Dorsal views of the pygidium.