From inside the progressive P. hemioliopterus the brand new relevant central area of the head rooftop is practically completely ornamented of the reticulating ridges and pits, with partners if any elongate, parallel ridges and sulci ( Fig. 4a). Regarding Acre Phractocephalus brand new central region of the skull rooftop has some elongate ridges and sulci and reticulating ridges and you can pits.

The new horizontal ethmoid limbs off P

2) Mesethmoid bones really wider ( Table step 1); dorsal surface commonly ornamented; prior boundary rarely emarginate in order to lightly round ( Fig. 3a).

The brand new mesethmoid limbs out of P. hemioliopterus is fairly thin-necked, reduced widely ornamented simply centrally and you will posteriorly, as well as prior boundary is emarginate or shallowly concave ( Fig. 4a). nassi.

3) Horizontal ethmoid maybe not excessive projecting anteriorly more than palatine condyle; its horizontal margin convex and you can reducing orbital level on the margin away from skull roof ( Fig. 3a).

hemioliopterus is even perhaps not excessively projecting anteriorly across the olfactory area otherwise palatine condyle; but it is concave laterally, and has a well defined orbital sulcus into margin of head rooftop ( Fig. 4a). On Acre Phractocephalus brand new lateral ethmoid strategies much anteriorly over the olfactory region and you will palatine condyle; it’s convex sideways, removing the orbital sulcus into the margin from head rooftop.

Progressive P. hemioliopterus enjoys an unbarred anterior cranial fontanelle in this a popular depression out of epiphyseal region ( Fig. 4a), whereas on Acre Phractocephalus new fontanelle and anxiety of your own epiphyseal area lack.

5) Supraoccipital process with game horizontal and you will posterolateral margins, rear margin concave medially; supraoccipital procedure long, in the dorsal consider totally covering altered prior backbone from Weberian advanced ( Fig. 3a).

The fresh opercle P

When you look at the modern P. hemioliopterus the new supraoccipital techniques was brief, for the dorsal evaluate not entirely level changed spinal vertebrae regarding Weberian advanced; this has angular lateral and you may posterolateral margins, and its particular posterior margin was abnormal to help you concave medially and you will hit a-deep unornamented expansion lower than prior nuchal dish ( Fig. 4a). About Acre Phractocephalus the latest supraoccipital techniques try long, entirely covering the Weberian state-of-the-art; the procedure provides angular edges and upright lateral margins, as well as rear ented expansion below anterior nuchal plate.

hemioliopterus is incompletely wrapped in reticulating ridges and you may pits ( Fig. 5c). The fresh new opercle is actually yet unknown on Acre Phractocephalus.

7) Cleithrum having rough ornamentation stretching together ventral edge creating external bulge otherwise « shoulder » lateral so you’re able to spine articulation; fat regarding « shoulder » terminating posteriorly, according to cancellation of articular retailer from pectoral lower back ( Figs. 5e-g).

The fresh new cleithrum from P. hemioliopterus does not have coarse ornamentation collectively ventral edge of « neck, » plus the horizontal fat of « shoulder » terminates rear to the stage regarding articular retailer of pectoral spine ( Figs. 5i, j). No cleithrum of one’s Acre Phractocephalus is known.

8) Pectoral back ornamentation controlled by rough subparallel ridges and sulci, and you may apparently pair reticulating ridges and you will pits ( Fig. 5h).

The latest pectoral lower back ornamentation away from P. hemioliopterus is controlled by the reticulating ridges and you may pits ( Fig. 5i). The new pectoral spine of Acre Phractocephalus is actually yet unknown.

Etymology. The newest Urumaco species of Phractocephalus is named to have Dr. Pedro Nass during the detection out-of his contributions to the systematics and you may morphology from pimelodid catfishes out-of South america.

Dysfunction. Discover Lundberg mais aussi al. (1988) to own dysfunction away from neurocranium (MCN.USB 72-85 PB) and extra dimensions. The second information is provided by the new holotype and you may has just acquired specimens.

Neurocranium, dorsal factor ( Fig. 3a). Information brand of skull whenever rectangular, width all over horizontal ethmoids equivalent to width round the sphenotics, horny Sapiosexual dating that widths a little below restriction depth round the pterotic wings; thickness around the pterotics contained dos.twenty five times within the (45% of) dorsal head size out of mesethmoid suggestion to help you posterior edge of supraoccipital processes. Body mainly apartment but margins curved a bit downwards and dorsal midline even more arched posteriorly. The skeleton ornamented having rough reticulating ridges and you can game pits and you will some longitudinally elongate ridges and you may grooves, except for olfactory pills and extremities out of mesethmoid cornua.