Into the modern P. hemioliopterus brand new relevant main section of the head rooftop is practically completely ornamented by the reticulating ridges and you can pits, having couples if any elongate, synchronous ridges and you will sulci ( Fig. 4a). Regarding the Acre Phractocephalus the fresh new main area of the head roof has many elongate ridges and you may sulci and additionally reticulating ridges and you will pits.
Brand new horizontal ethmoid limbs from P
2) Mesethmoid bone really wider ( Dining table 1); dorsal facial skin extensively ornamented; anterior line rarely emarginate to gently round ( Fig. 3a).
This new mesethmoid bones of P. hemioliopterus is relatively slim-necked, quicker commonly ornamented simply centrally and you can posteriorly, and its own anterior line was emarginate otherwise shallowly concave ( Fig. 4a). nassi.
3) Lateral ethmoid not excessively projecting anteriorly more palatine condyle; the horizontal margin convex and you may eliminating orbital level to your margin from skull rooftop ( Fig. 3a).
hemioliopterus is even not continuously projecting anteriorly along side olfactory region otherwise palatine condyle; but it’s concave sideways, possesses a highly outlined orbital sulcus for the margin out-of skull roof ( Fig. 4a). Regarding Acre Phractocephalus the fresh lateral ethmoid methods far anteriorly more brand new olfactory region and you will palatine condyle; it is convex sideways, eliminating the latest orbital sulcus on the margin from skull rooftop.
Modern P. hemioliopterus have an unbarred anterior cranial fontanelle within this a well known despair from epiphyseal part ( Fig. 4a), while throughout the Acre Phractocephalus new fontanelle and you will anxiety of epiphyseal part are lacking.
5) Supraoccipital processes with round lateral and you can posterolateral margins, posterior margin concave medially; supraoccipital process much time, inside the dorsal evaluate totally level modified anterior vertebrae from Weberian advanced ( Fig. 3a).
This new opercle P
For the progressive P. hemioliopterus the fresh supraoccipital process is small, in dorsal see not entirely level altered vertebrae off Weberian cutting-edge; it offers angular lateral and you may posterolateral margins, and its particular rear margin is actually irregular in order to concave medially and you can impact an intense unornamented expansion below prior nuchal dish ( Fig. 4a). Regarding Acre Phractocephalus the latest supraoccipital process is enough time, entirely since the Weberian complex; their process keeps angular sides and you can straight horizontal margins, and its particular rear ented expansion less than anterior nuchal dish.
hemioliopterus are incompletely wrapped in reticulating ridges and you will pits ( Fig. 5c). The newest opercle try at this point unfamiliar on the Acre Phractocephalus.
7) Cleithrum with coarse ornamentation extending along ventral boundary developing external fat or “shoulder” lateral in order to lower back articulation; fat from “shoulder” terminating posteriorly, in line with termination off articular retailer regarding pectoral back ( Figs. 5e-g).
The new cleithrum regarding P. hemioliopterus does not have coarse ornamentation collectively ventral side of “neck,” and horizontal fat out-of “shoulder” terminates posterior to the stage off articular retailer out of pectoral spine ( Figs. 5i, j). Zero cleithrum of your own Acre https://datingmentor.org/pl/shaadi-recenzja/ Phractocephalus has been found.
8) Pectoral spine ornamentation controlled from the rough subparallel ridges and sulci, and you can seemingly pair reticulating ridges and you can pits ( Fig. 5h).
This new pectoral back ornamentation off P. hemioliopterus is reigned over by the reticulating ridges and pits ( Fig. 5i). The brand new pectoral spine of the Acre Phractocephalus are yet , unfamiliar.
Etymology. The brand new Urumaco species of Phractocephalus is called to possess Dr. Pedro Nass into the identification of their benefits on systematics and you can morphology off pimelodid catfishes of South usa.
Malfunction. Find Lundberg et al. (1988) for description of neurocranium (MCN.USB 72-85 PB) and additional measurements. The next information is available with the latest holotype and you may recently received specimens.
Neurocranium, dorsal factor ( Fig. 3a). Definition type of skull approximately rectangular, depth round the horizontal ethmoids equal to thickness all over sphenotics, that widths some below restrict width across the pterotic wings; thickness round the pterotics consisted of 2.twenty five minutes inside the (45% of) dorsal skull length from mesethmoid tip so you can posterior edge of supraoccipital techniques. Facial skin mostly apartment however, margins rounded quite down and you will dorsal midline much more curved posteriorly. Most of the bones ornamented with rough reticulating ridges and you will circular pits and you may some longitudinally elongate ridges and you will grooves, with the exception of olfactory supplements and extremities of mesethmoid cornua.