In progressive P. hemioliopterus brand new involved central side of the skull roof is almost totally ornamented by the reticulating ridges and you will pits, having pair or no elongate, synchronous ridges and you can sulci ( Fig. 4a). Throughout the Acre Phractocephalus the fresh new main area of the head rooftop has many elongate ridges and you will sulci also reticulating ridges and pits.
This new horizontal ethmoid bones away from P
2) Mesethmoid bones very wider ( Desk 1); dorsal skin commonly ornamented; prior border barely emarginate to gently rounded ( Fig. 3a).
The fresh mesethmoid limbs off P. hemioliopterus is relatively thin-necked, shorter extensively ornamented only centrally and you will posteriorly, and its own anterior line is emarginate or shallowly concave ( Fig. 4a). nassi.
3) Horizontal ethmoid perhaps not excessive projecting anteriorly more than palatine condyle; their lateral margin convex and you can removing orbital notch into the margin regarding skull roof ( Fig. 3a).
hemioliopterus is also not an excessive amount of projecting anteriorly over the olfactory region otherwise palatine condyle; however it is concave laterally, and has now a highly laid out orbital sulcus for the margin away from head roof ( Fig. 4a). About Acre Phractocephalus the fresh new lateral ethmoid systems much anteriorly more this new olfactory region and you can palatine condyle; it is convex laterally, removing the latest orbital sulcus towards margin off skull rooftop.
Progressive P. hemioliopterus have an unbarred prior cranial fontanelle in this a popular depression from epiphyseal escort service Santa Maria part ( Fig. 4a), while from the Acre Phractocephalus the brand new fontanelle and you can depression of epiphyseal part are lacking.
5) Supraoccipital processes having round lateral and you will posterolateral margins, rear margin concave medially; supraoccipital processes a lot of time, within the dorsal examine entirely covering altered anterior vertebrae out of Weberian cutting-edge ( Fig. 3a).
New opercle P
When you look at the modern P. hemioliopterus this new supraoccipital processes is actually short, for the dorsal have a look at perhaps not entirely layer modified backbone out-of Weberian state-of-the-art; it has angular horizontal and posterolateral margins, and its particular posterior margin is unusual so you’re able to concave medially and hit an intense unornamented expansion less than anterior nuchal dish ( Fig. 4a). In the Acre Phractocephalus the new supraoccipital procedure try much time, completely within the Weberian cutting-edge; their processes enjoys angular sides and you will straight horizontal margins, as well as rear ented extension less than anterior nuchal plate.
hemioliopterus is actually incompletely wrapped in reticulating ridges and you may pits ( Fig. 5c). This new opercle is so far not familiar throughout the Acre Phractocephalus.
7) Cleithrum having coarse ornamentation stretching together ventral line forming outward pouch or “shoulder” horizontal in order to lower back articulation; fat from “shoulder” terminating posteriorly, in accordance with cancellation from articular socket from pectoral lower back ( Figs. 5e-g).
This new cleithrum off P. hemioliopterus does not have rough ornamentation together ventral edge of “neck,” in addition to horizontal fat out-of “shoulder” terminates rear to the point out of articular retailer off pectoral back ( Figs. 5i, j). Zero cleithrum of one’s Acre Phractocephalus has been seen.
8) Pectoral spine ornamentation reigned over from the coarse subparallel ridges and sulci, and apparently couple reticulating ridges and you can pits ( Fig. 5h).
The newest pectoral lower back ornamentation off P. hemioliopterus was ruled by the reticulating ridges and you can pits ( Fig. 5i). The latest pectoral back of your Acre Phractocephalus are but really unfamiliar.
Etymology. New Urumaco types of Phractocephalus is named to have Dr. Pedro Nass in the recognition of his contributions with the systematics and you can morphology off pimelodid catfishes away from South usa.
Breakdown. See Lundberg ainsi que al. (1988) to have dysfunction out-of neurocranium (MCN.USB 72-85 PB) and extra dimensions. Another information is provided by the latest holotype and recently obtained specimens.
Neurocranium, dorsal factor ( Fig. 3a). Information version of skull approximately rectangular, thickness across the horizontal ethmoids comparable to depth round the sphenotics, and they widths a little below restrict thickness across the pterotic wings; thickness all over pterotics consisted of dos.twenty-five minutes inside (45% of) dorsal skull length out-of mesethmoid idea to posterior side of supraoccipital processes. Surface mainly flat however, margins rounded somewhat downwards and you can dorsal midline all the more arched posteriorly. All of the bones ornamented which have coarse reticulating ridges and you will game pits and you may particular longitudinally elongate ridges and you will grooves, apart from olfactory drugs and you can extremities off mesethmoid cornua.