The new mesethmoid bones of Acre Phractocephalus is similar to one out-of ?P

Within the modern P. hemioliopterus the latest associated main section of the skull rooftop is practically entirely ornamented of the reticulating ridges and you will pits, having couples or no elongate, parallel ridges and you will sulci ( Fig. 4a). About Acre Phractocephalus the latest central section of the head rooftop has many elongate ridges and you may sulci and additionally reticulating ridges and you will pits.

New horizontal ethmoid bone from P

2) Mesethmoid bone most large ( Desk 1); dorsal epidermis widely ornamented; prior boundary barely emarginate to softly circular ( Fig. 3a).

The mesethmoid limbs out of P. hemioliopterus is relatively narrow-necked, less generally ornamented just centrally and posteriorly, and its anterior edge are emarginate otherwise shallowly concave ( Fig. 4a). nassi.

3) Horizontal ethmoid maybe not excessively projecting anteriorly more than palatine condyle; the lateral margin convex and you can eliminating orbital level towards the margin of head rooftop ( Fig. 3a).

hemioliopterus is even not too much projecting anteriorly along side olfactory part or palatine condyle; however it is concave laterally, and has now a proper outlined orbital sulcus toward margin regarding head rooftop ( Fig. 4a). Regarding Acre Phractocephalus the fresh horizontal ethmoid plans far anteriorly more this new olfactory area and you can palatine condyle; it is convex laterally, reducing the fresh orbital sulcus into the margin of skull roof.

Progressive P. hemioliopterus have an unbarred prior cranial fontanelle contained in this popular anxiety away from epiphyseal area ( Fig. 4a), while about Acre Phractocephalus brand new fontanelle and you can anxiety of your epiphyseal part lack.

5) Supraoccipital processes that have round lateral and you will posterolateral margins, rear margin concave medially; supraoccipital techniques enough time, when you look at the dorsal glance at completely coating changed anterior vertebrae of escort girl South Bend Weberian state-of-the-art ( Fig. 3a).

The fresh new opercle P

Inside the modern P. hemioliopterus the newest supraoccipital techniques are short, in dorsal view maybe not completely layer modified vertebrae of Weberian advanced; it’s got angular horizontal and you will posterolateral margins, and its particular posterior margin was unusual so you can concave medially and you may impact a-deep unornamented expansion below prior nuchal plate ( Fig. 4a). Throughout the Acre Phractocephalus the fresh supraoccipital processes is actually a lot of time, totally within the Weberian state-of-the-art; their process keeps angular corners and straight lateral margins, and its particular rear ented extension less than anterior nuchal dish.

hemioliopterus was incompletely covered with reticulating ridges and you can pits ( Fig. 5c). The latest opercle try at this point not familiar regarding Acre Phractocephalus.

7) Cleithrum having coarse ornamentation extending with each other ventral edge building external bulge otherwise «shoulder» horizontal to help you back articulation; bulge regarding «shoulder» terminating posteriorly, in line with termination of articular outlet from pectoral back ( Figs. 5e-g).

Brand new cleithrum regarding P. hemioliopterus does not have coarse ornamentation with each other ventral edge of «shoulder,» in addition to horizontal fat away from «shoulder» terminates rear to the point regarding articular socket out-of pectoral spine ( Figs. 5i, j). Zero cleithrum of one’s Acre Phractocephalus has been found.

8) Pectoral back ornamentation reigned over because of the rough subparallel ridges and you can sulci, and you may relatively couple reticulating ridges and you may pits ( Fig. 5h).

The latest pectoral lower back ornamentation of P. hemioliopterus try controlled from the reticulating ridges and you can pits ( Fig. 5i). The latest pectoral spine of your Acre Phractocephalus is yet , not familiar.

Etymology. The fresh new Urumaco types of Phractocephalus is known as having Dr. Pedro Nass during the recognition from their benefits towards the systematics and you may morphology from pimelodid catfishes regarding South usa.

Dysfunction. Find Lundberg et al. (1988) getting dysfunction out-of neurocranium (MCN.USB 72-85 PB) and additional measurements. Next data is available with new holotype and you can has just gotten specimens.

Neurocranium, dorsal factor ( Fig. 3a). Information sort of skull everything square, thickness around the lateral ethmoids equivalent to width all over sphenotics, that widths quite lower than restriction width round the pterotic wings; width across pterotics contains 2.twenty five times from inside the (45% of) dorsal head duration from mesethmoid suggestion to help you rear edge of supraoccipital techniques. Body mostly flat however, margins curved a bit down and you will dorsal midline all the more curved posteriorly. Every skeleton ornamented having rough reticulating ridges and you can rounded pits and you can some longitudinally elongate ridges and you can grooves, except for olfactory products and you can extremities of mesethmoid cornua.