Inside the progressive P. hemioliopterus the relevant main region of the head roof is practically completely ornamented by reticulating ridges and you will pits, with partners or no elongate, synchronous ridges and you may sulci ( Fig. 4a). In the Acre Phractocephalus new main region of the head rooftop has some elongate ridges and you can sulci together with reticulating ridges and you may pits.
The fresh lateral ethmoid limbs of P
2) Mesethmoid bones extremely broad ( Dining table 1); dorsal body commonly ornamented; anterior line rarely emarginate in order to softly circular ( Fig. 3a).
New mesethmoid limbs out of P. hemioliopterus is fairly narrow-necked, less widely ornamented just centrally and posteriorly, as well as prior edge is actually emarginate otherwise shallowly concave ( Fig. 4a). nassi.
3) Horizontal ethmoid not an excessive amount of projecting anteriorly over palatine condyle; their horizontal margin convex and you will eliminating orbital level to your margin regarding head rooftop ( Fig. 3a).
hemioliopterus is additionally maybe not too-much projecting anteriorly along side olfactory area or palatine condyle; however it is concave sideways, and contains a highly laid out orbital sulcus on the margin of head rooftop ( Fig. 4a). Regarding the Acre Phractocephalus the newest horizontal ethmoid strategies much anteriorly more the new olfactory region and you may palatine condyle; it’s convex sideways, getting rid of the brand new orbital sulcus to your margin out of head roof.
Progressive P. hemioliopterus keeps an open anterior cranial fontanelle contained in this a favorite anxiety out-of epiphyseal part ( Fig. 4a), whereas in the Acre Phractocephalus this new fontanelle and you will depression of epiphyseal area are lacking.
5) Supraoccipital processes with circular lateral and you can posterolateral margins, posterior margin concave medially; supraoccipital processes a lot of time, inside dorsal take a look at totally level changed anterior spinal vertebrae regarding Weberian advanced ( Fig. 3a).
Brand new opercle P
In modern P. hemioliopterus the new supraoccipital procedure are short, in dorsal consider perhaps not completely level changed spinal vertebrae away from Weberian state-of-the-art; it’s got angular lateral and you may posterolateral margins, as well as rear margin is abnormal to concave medially and you will results a deep unornamented extension less than anterior nuchal plate ( Fig. 4a). Throughout the Acre Phractocephalus brand new supraoccipital process is enough time, entirely within the Weberian state-of-the-art; the procedure enjoys angular corners and you may straight lateral margins, and its own rear ented extension lower than anterior nuchal dish.
hemioliopterus was incompletely wrapped in reticulating ridges and you will pits ( Fig. 5c). New opercle is thus far not familiar about Acre Phractocephalus.
7) Cleithrum which have rough ornamentation extending together ventral edge forming external bulge or “shoulder” lateral so you can lower back articulation; fat off “shoulder” terminating posteriorly, in accordance with cancellation from articular retailer of pectoral lower back ( Figs. 5e-g).
This new cleithrum away from P. hemioliopterus lacks rough ornamentation with each other ventral side of “neck,” while the horizontal bulge from “shoulder” terminates rear to the stage off articular socket away from pectoral back ( Figs. 5i, j). Zero cleithrum of one’s Acre Phractocephalus has been seen.
8) Pectoral spine ornamentation reigned over from the rough subparallel ridges and sulci, and you can relatively couple reticulating ridges and you will pits ( Fig. 5h).
The newest pectoral back ornamentation from P. hemioliopterus are ruled because of the reticulating ridges and you can pits ( Fig. 5i). This new pectoral back of one’s Acre Phractocephalus was but really unfamiliar.
Etymology. The fresh Urumaco species of Phractocephalus is named to have Dr. Pedro Nass when you look at the identification from their efforts on the systematics and you may morphology regarding pimelodid catfishes from South usa.
Description. Come across Lundberg ainsi que al. (1988) having description regarding neurocranium (MCN.USB 72-85 PB) and additional proportions. sober video chat Next data is available with this new holotype and you will has just acquired specimens.
Neurocranium, dorsal factor ( Fig. 3a). Information variety of skull everything rectangular, width all over horizontal ethmoids equivalent to width all over sphenotics, that widths some less than restriction depth round the pterotic wings; width across the pterotics contains 2.25 moments during the (45% of) dorsal head size away from mesethmoid idea so you’re able to posterior edge of supraoccipital processes. Skin primarily apartment however, margins rounded slightly down and you can dorsal midline even more curved posteriorly. All skeleton ornamented having rough reticulating ridges and round pits and you will particular longitudinally elongate ridges and you can grooves, apart from olfactory pills and you will extremities of mesethmoid cornua.