During the progressive P. hemioliopterus the latest involved central side of the head roof is nearly totally ornamented from the reticulating ridges and you will pits, with few if any elongate, parallel ridges and sulci ( Fig. 4a). In the Acre Phractocephalus this new main section of the skull rooftop has many elongate ridges and you will sulci including reticulating ridges and you will pits.
The new horizontal ethmoid bone off P
2) Mesethmoid limbs most broad ( Table step 1); dorsal surface generally ornamented; anterior edge rarely emarginate to help you carefully round ( Fig. 3a).
The fresh mesethmoid bones from P. hemioliopterus is fairly slim-necked, smaller widely ornamented merely centrally and you will posteriorly, and its particular anterior line was emarginate otherwise shallowly concave ( Fig. 4a). nassi.
3) Horizontal ethmoid perhaps not way too much projecting anteriorly more than palatine condyle; its horizontal margin convex and removing orbital notch towards margin away from skull rooftop ( Fig. 3a).
hemioliopterus is even maybe not an excessive amount of projecting anteriorly along side olfactory part otherwise palatine condyle; but it’s concave sideways, and contains a highly laid out orbital sulcus for the margin away from skull rooftop ( Fig. 4a). Regarding the Acre Phractocephalus new horizontal ethmoid programs far anteriorly more than the olfactory area and palatine condyle; it’s convex sideways, getting rid of the brand new orbital sulcus with the margin regarding head rooftop.
Modern P. hemioliopterus provides an open anterior cranial fontanelle in this a well known depression away from epiphyseal part ( Fig. 4a), whereas regarding Acre Phractocephalus brand new fontanelle and you may despair of epiphyseal part are lacking.
5) Supraoccipital procedure with rounded lateral and you can posterolateral margins, rear margin concave medially; supraoccipital process enough time, during the dorsal see entirely level altered prior spinal vertebrae off Weberian cutting-edge ( Fig. 3a).
This new opercle P
Within the progressive P. hemioliopterus the supraoccipital procedure try small, into the dorsal examine maybe not entirely coating altered backbone of Weberian cutting-edge; it offers angular lateral and you can posterolateral margins, and its particular rear margin is actually abnormal so you can concave medially and you can bearing a-deep unornamented expansion lower than anterior nuchal dish ( Fig. 4a). On the Acre Phractocephalus the newest supraoccipital processes are long, entirely within the Weberian advanced; its processes have angular edges and you may straight horizontal margins, and its particular rear ented expansion less than prior nuchal dish.
hemioliopterus try incompletely covered with reticulating ridges and pits ( Fig. 5c). The fresh opercle are so far not familiar regarding Acre Phractocephalus.
7) Cleithrum with rough ornamentation extending collectively ventral edge forming outward bulge or „shoulder” horizontal in order to spine articulation; bulge out of „shoulder” terminating posteriorly, prior to termination regarding articular retailer out of pectoral back ( Figs. 5e-g).
The fresh new cleithrum from P. hemioliopterus lacks rough ornamentation collectively ventral side of „neck,” therefore the lateral pouch out of „shoulder” terminates posterior to the point of articular socket regarding pectoral spine ( Figs. 5i, j). No cleithrum of one’s Acre Phractocephalus has been seen.
8) Pectoral lower back ornamentation reigned over because of the rough subparallel ridges and sulci, and you can apparently few reticulating ridges and you will pits ( Fig. 5h).
The fresh pectoral back ornamentation regarding P. hemioliopterus is dominated by the reticulating ridges and you may pits ( Fig. 5i). This new pectoral lower back of Acre Phractocephalus try yet not familiar.
Etymology. The fresh Urumaco types of Phractocephalus is named to own Dr. Pedro Nass in recognition off their benefits into systematics and you may morphology away from pimelodid catfishes off South usa.
Description. See Lundberg ainsi que al. (1988) to possess malfunction out of neurocranium (MCN.USB 72-85 PB) and additional proportions. Next information is available with the new holotype and you will recently obtained specimens.
Neurocranium, dorsal element ( Fig. 3a). Definition version of Sex dating service skull around square, width around the lateral ethmoids equal to depth all over sphenotics, and they widths somewhat below limit width round the pterotic wings; width across pterotics consisted of dos.25 moments for the (45% of) dorsal skull duration from mesethmoid suggestion in order to rear edge of supraoccipital techniques. Body mainly apartment but margins rounded a little downwards and you will dorsal midline even more curved posteriorly. All the skeleton ornamented which have rough reticulating ridges and you can game pits and you can particular longitudinally elongate ridges and you may grooves, apart from olfactory supplements and extremities away from mesethmoid cornua.
