Into the progressive P. hemioliopterus the fresh new corresponding central area of the head rooftop is almost entirely ornamented by reticulating ridges and pits, that have couples if any elongate, synchronous ridges and you can sulci ( Fig. 4a). From the Acre Phractocephalus this new main section of the head roof has some elongate ridges and you may sulci along with reticulating ridges and you can pits.
The latest lateral ethmoid limbs regarding P
2) Mesethmoid bone really greater ( Table 1); dorsal skin extensively ornamented; anterior border barely emarginate to gently circular ( Fig. 3a).
The brand new mesethmoid bone out-of P. hemioliopterus is fairly narrow-necked, reduced generally ornamented merely centrally and you may posteriorly, and its particular prior border try emarginate or shallowly concave ( Fig. 4a). nassi.
3) Lateral ethmoid maybe not too much projecting anteriorly over sdc singles dating site palatine condyle; their lateral margin convex and you will getting rid of orbital level into the margin regarding skull roof ( Fig. 3a).
hemioliopterus is additionally not way too much projecting anteriorly across the olfactory area or palatine condyle; but it is concave sideways, and has a highly discussed orbital sulcus to your margin out of skull rooftop ( Fig. 4a). Throughout the Acre Phractocephalus the brand new lateral ethmoid tactics far anteriorly over the new olfactory part and you can palatine condyle; it’s convex laterally, removing the brand new orbital sulcus towards the margin regarding skull roof.
Modern P. hemioliopterus keeps an open anterior cranial fontanelle in this popular anxiety regarding epiphyseal part ( Fig. 4a), while from the Acre Phractocephalus the newest fontanelle and you will anxiety of the epiphyseal region are lacking.
5) Supraoccipital procedure with circular horizontal and you can posterolateral margins, rear margin concave medially; supraoccipital techniques enough time, for the dorsal have a look at completely level modified anterior vertebrae out-of Weberian cutting-edge ( Fig. 3a).
The fresh new opercle P
Within the modern P. hemioliopterus the brand new supraoccipital techniques try short, in the dorsal examine not completely level modified vertebrae from Weberian cutting-edge; it’s got angular horizontal and you will posterolateral margins, and its particular rear margin are unpredictable to help you concave medially and results a deep unornamented expansion less than prior nuchal dish ( Fig. 4a). In the Acre Phractocephalus the fresh supraoccipital procedure try enough time, entirely within the Weberian cutting-edge; the process keeps angular edges and you will straight lateral margins, and its own posterior ented expansion less than prior nuchal dish.
hemioliopterus was incompletely covered with reticulating ridges and you can pits ( Fig. 5c). New opercle was yet unfamiliar on the Acre Phractocephalus.
7) Cleithrum which have coarse ornamentation extending together ventral boundary developing external pouch otherwise “shoulder” horizontal to help you back articulation; fat away from “shoulder” terminating posteriorly, in accordance with cancellation from articular retailer of pectoral back ( Figs. 5e-g).
The cleithrum regarding P. hemioliopterus lacks rough ornamentation along ventral side of “shoulder,” while the lateral fat of “shoulder” terminates posterior to the stage regarding articular socket regarding pectoral lower back ( Figs. 5i, j). No cleithrum of your own Acre Phractocephalus has been discovered.
8) Pectoral lower back ornamentation controlled by rough subparallel ridges and you can sulci, and you will seemingly few reticulating ridges and you may pits ( Fig. 5h).
The new pectoral back ornamentation out-of P. hemioliopterus are ruled because of the reticulating ridges and you may pits ( Fig. 5i). The new pectoral spine of one’s Acre Phractocephalus are but really unknown.
Etymology. The brand new Urumaco types of Phractocephalus is known as to own Dr. Pedro Nass when you look at the identification regarding his benefits toward systematics and you can morphology out of pimelodid catfishes away from South america.
Description. Come across Lundberg ainsi que al. (1988) to own description regarding neurocranium (MCN.USB 72-85 PB) and extra measurements. The next info is available with the holotype and you may recently acquired specimens.
Neurocranium, dorsal element ( Fig. 3a). Definition type of skull whenever rectangular, depth round the horizontal ethmoids equal to thickness across sphenotics, and these widths a little below restriction depth across the pterotic wings; depth across pterotics contained 2.25 minutes during the (45% of) dorsal skull length out-of mesethmoid idea to posterior edge of supraoccipital processes. Body primarily apartment however, margins curved slightly downward and you can dorsal midline much more arched posteriorly. All of the bones ornamented that have rough reticulating ridges and circular pits and specific longitudinally elongate ridges and you may grooves, except for olfactory supplements and extremities of mesethmoid cornua.