The mesethmoid limbs of one’s Acre Phractocephalus is similar to that out of ?P
From inside the progressive P. hemioliopterus new involved main section of the head rooftop is almost entirely ornamented of the reticulating ridges and pits, that have couples if any elongate, synchronous ridges and you will sulci ( Fig. 4a). From the Acre Phractocephalus the central area of the skull rooftop has some elongate ridges and you can sulci and reticulating ridges and you will pits.
Brand new horizontal ethmoid bones out-of P
2) Mesethmoid limbs very wider ( Dining table 1); dorsal facial skin generally ornamented; anterior edge barely emarginate so you can carefully game ( Fig. 3a).
The new mesethmoid bones away from P. hemioliopterus is relatively slim-necked, shorter extensively ornamented only centrally and posteriorly, and its prior boundary was emarginate otherwise shallowly concave ( Fig. 4a). nassi.
3) Lateral ethmoid perhaps not way too much projecting anteriorly more palatine condyle; its horizontal margin convex and you can getting rid of orbital level with the margin from skull roof ( Fig. 3a).
hemioliopterus is also not excessively projecting anteriorly along side olfactory region or palatine condyle; but it is concave sideways, and has a proper outlined orbital sulcus on the margin off head roof ( Fig. 4a). About Acre Phractocephalus the fresh new horizontal ethmoid plans much anteriorly more than the latest olfactory area and palatine condyle; it’s convex laterally, removing new orbital sulcus towards the margin away from head rooftop.
Progressive P. hemioliopterus features an unbarred prior cranial fontanelle within popular anxiety away from epiphyseal part ( Fig. 4a), while in the Acre Phractocephalus the fresh new fontanelle and you will anxiety of your own epiphyseal region lack.
5) Supraoccipital process that have game lateral and you may posterolateral margins, posterior margin concave medially; supraoccipital processes long, in dorsal have a look at totally level changed anterior backbone out of Weberian advanced ( Fig. 3a).
The opercle P
Inside modern P. hemioliopterus the newest supraoccipital procedure are small, into the dorsal have a look at maybe not totally level changed backbone out of Weberian cutting-edge; it offers angular horizontal and you can posterolateral margins, and its own posterior margin are unusual so you’re able to concave medially and you can hit a deep unornamented extension below prior nuchal dish ( Fig. 4a). Regarding the Acre Phractocephalus the fresh supraoccipital procedure was enough time, entirely within the Weberian complex; their processes features angular corners and you may straight lateral margins, as well as rear ented extension less than prior nuchal plate.
hemioliopterus try incompletely wrapped in reticulating ridges and you can pits ( Fig. 5c). The brand new opercle try so far unfamiliar regarding Acre Phractocephalus.
7) Cleithrum which have rough ornamentation extending collectively ventral border building external fat otherwise “shoulder” horizontal to help you spine articulation; bulge off “shoulder” terminating posteriorly, in line with termination off articular outlet away from pectoral spine ( Figs. 5e-g).
The latest cleithrum of P. hemioliopterus lacks coarse ornamentation together ventral edge of “neck,” and the lateral fat regarding “shoulder” terminates posterior concise out of articular outlet from pectoral back ( Figs. 5i, j). Zero cleithrum of the Acre Phractocephalus has been seen.
8) Pectoral back ornamentation controlled of the coarse subparallel ridges and you can sulci, and you will seemingly couples reticulating ridges and you will pits ( Fig. 5h).
The fresh pectoral back ornamentation away from P. hemioliopterus are controlled by the reticulating ridges and pits ( Fig. 5i). The latest https://datingmentor.org/escort/santa-clarita/ pectoral back of the Acre Phractocephalus was but really not familiar.
Etymology. The latest Urumaco species of Phractocephalus is called to possess Dr. Pedro Nass from inside the identification off their contributions to the systematics and you may morphology off pimelodid catfishes of South america.
Dysfunction. Get a hold of Lundberg et al. (1988) having breakdown out of neurocranium (MCN.USB 72-85 PB) and extra measurements. The following info is provided with the latest holotype and you can has just acquired specimens.
Neurocranium, dorsal aspect ( Fig. 3a). Definition types of head just as much as square, depth across the horizontal ethmoids equal to depth across the sphenotics, that widths a bit less than restriction thickness all over pterotic wings; depth across the pterotics contained dos.twenty-five times when you look at the (45% of) dorsal skull duration out-of mesethmoid suggestion so you’re able to posterior edge of supraoccipital procedure. Skin mostly apartment however, margins rounded quite down and dorsal midline even more curved posteriorly. The skeleton ornamented with coarse reticulating ridges and you can game pits and you may specific longitudinally elongate ridges and you may grooves, with the exception of olfactory medicine and extremities away from mesethmoid cornua.