Into the modern P. hemioliopterus the newest corresponding main side of the skull rooftop is nearly completely ornamented by reticulating ridges and you can pits, having partners or no elongate, parallel ridges and you may sulci ( Fig. 4a). On the Acre Phractocephalus the latest central region of the head roof has some elongate ridges and you will sulci along with reticulating ridges and you will pits.
The fresh new horizontal ethmoid bones out of P
2) Mesethmoid limbs very wider ( Desk step one); dorsal skin extensively ornamented; prior edge hardly emarginate so you’re able to lightly rounded ( Fig. 3a).
The fresh new mesethmoid bone of P. hemioliopterus is fairly thin-necked, reduced generally ornamented just centrally and you can posteriorly, as well as anterior border are emarginate or shallowly concave ( Fig. 4a). nassi.
3) Horizontal ethmoid perhaps not extreme projecting anteriorly more than palatine condyle; their lateral margin convex and getting rid of orbital level into the margin from skull rooftop ( Fig. 3a).
hemioliopterus is even not excessive projecting anteriorly across the olfactory area or palatine condyle; but it is concave laterally, features a proper laid out orbital sulcus to the margin of skull rooftop ( Fig. 4a). Regarding Acre Phractocephalus new lateral ethmoid projects much anteriorly over the olfactory part and you may palatine condyle; it’s convex sideways, getting rid of the orbital sulcus into the margin of skull rooftop.
Progressive P. hemioliopterus provides an unbarred prior cranial fontanelle in this a popular despair off epiphyseal area ( Fig. 4a), whereas on Acre Phractocephalus the latest fontanelle and despair of your epiphyseal region are lacking.
5) Supraoccipital techniques that have round horizontal and you may posterolateral margins, posterior margin concave medially; supraoccipital procedure a lot of time, during the dorsal glance at totally level altered anterior spinal vertebrae regarding Weberian complex ( Fig. 3a).
Brand new opercle P
Inside the modern P. hemioliopterus the brand new supraoccipital procedure are small, into the dorsal glance at maybe not entirely covering modified backbone from Weberian advanced; it has angular horizontal and you will posterolateral margins, and its particular posterior margin are irregular to concave medially and you can results a deep unornamented extension lower than anterior nuchal dish ( Fig. 4a). From the Acre Phractocephalus the supraoccipital procedure try a lot of time, totally within the Weberian advanced; their process provides angular edges and you will upright horizontal margins, and its rear ented extension lower than anterior nuchal dish.
hemioliopterus is incompletely covered with reticulating ridges and you will pits ( Fig. 5c). The newest opercle is actually thus far not familiar throughout the Acre Phractocephalus.
7) Cleithrum with rough ornamentation stretching with each other ventral line building outward pouch or “shoulder” lateral to help you back articulation; fat out-of “shoulder” terminating posteriorly, in line with cancellation out of articular socket from pectoral lower back ( Figs. 5e-g).
The new cleithrum out of P. hemioliopterus does not have rough ornamentation together ventral edge of “shoulder,” and the horizontal bulge off “shoulder” terminates posterior to the level away from articular retailer from pectoral spine ( Figs. 5i, j). Zero cleithrum of the Acre Phractocephalus has been discovered.
8) Pectoral spine ornamentation dominated from the rough subparallel ridges and you may sulci, and relatively couple reticulating ridges and pits ( Fig. 5h).
The newest pectoral lower back ornamentation off P. hemioliopterus was reigned over of the reticulating ridges and you may pits ( Fig. 5i). The brand new pectoral back of one’s Acre Phractocephalus are yet not familiar.
Etymology. The latest Urumaco species of Phractocephalus is known as to possess Dr. Pedro Nass in recognition from their contributions for the systematics and you can morphology regarding pimelodid catfishes from South usa.
Malfunction. Look for Lundberg et al. (1988) to possess malfunction out of neurocranium (MCN.USB 72-85 PB) and additional specifications. The next information is available with the holotype and you will has just obtained specimens.
Neurocranium, dorsal factor ( Fig. 3a). Information version of head whenever rectangular, width across the lateral ethmoids equivalent to width around the sphenotics, and these widths quite lower than limitation thickness round the pterotic wings; depth around the pterotics consisted of dos.twenty-five moments during the (45% of) dorsal head size out of mesethmoid suggestion so you can rear side of supraoccipital process. Body mainly flat however, margins curved a little down and dorsal midline much more curved posteriorly. All of the skeleton ornamented that have coarse reticulating ridges and game pits and you may certain longitudinally elongate ridges and you will grooves, except for olfactory medicine and extremities out-of mesethmoid cornua.
