In progressive P. hemioliopterus the fresh new associated main region of the skull roof is virtually entirely ornamented because of the reticulating ridges and you can pits, with couple or no elongate, synchronous ridges and you can sulci ( Fig. 4a). About Acre Phractocephalus this new central section of the head rooftop has many elongate ridges and you can sulci together with reticulating ridges and you will pits.
This new horizontal ethmoid bones of P
2) Mesethmoid limbs very broad ( Dining table step one); dorsal epidermis extensively ornamented; anterior boundary rarely emarginate in order to softly round ( Fig. 3a).
New mesethmoid bones off P. hemioliopterus is fairly thin-necked, faster extensively ornamented just centrally and you will posteriorly, and its anterior line was emarginate otherwise shallowly concave ( Fig. 4a). nassi.
3) Lateral ethmoid not a lot of projecting anteriorly more than palatine condyle; its horizontal margin convex and eliminating orbital level towards margin from skull rooftop ( Fig. 3a).
hemioliopterus is additionally maybe not excessive projecting anteriorly over the olfactory region or palatine condyle; but it is concave laterally, best single men dating site Los Angeles features a proper discussed orbital sulcus for the margin out-of head rooftop ( Fig. 4a). Regarding the Acre Phractocephalus this new horizontal ethmoid plans much anteriorly more the fresh olfactory area and you can palatine condyle; it’s convex laterally, removing the fresh orbital sulcus into the margin from skull roof.
Progressive P. hemioliopterus possess an unbarred anterior cranial fontanelle within this a prominent despair off epiphyseal area ( Fig. 4a), whereas in the Acre Phractocephalus the newest fontanelle and you may depression of your epiphyseal region lack.
5) Supraoccipital processes which have rounded lateral and you may posterolateral margins, posterior margin concave medially; supraoccipital procedure much time, when you look at the dorsal consider totally level modified anterior backbone regarding Weberian advanced ( Fig. 3a).
This new opercle P
Inside the modern P. hemioliopterus the brand new supraoccipital process are brief, inside dorsal see maybe not entirely coating changed vertebrae of Weberian cutting-edge; it has got angular horizontal and posterolateral margins, as well as posterior margin was unpredictable to concave medially and you can influence a-deep unornamented expansion lower than anterior nuchal dish ( Fig. 4a). Regarding the Acre Phractocephalus the fresh supraoccipital techniques try a lot of time, entirely covering the Weberian complex; the process keeps angular sides and you will upright lateral margins, as well as rear ented extension less than prior nuchal dish.
hemioliopterus was incompletely wrapped in reticulating ridges and you may pits ( Fig. 5c). New opercle was up to now unfamiliar on Acre Phractocephalus.
7) Cleithrum having rough ornamentation stretching together ventral edge developing outward fat otherwise “shoulder” horizontal in order to back articulation; fat out of “shoulder” terminating posteriorly, in accordance with termination out-of articular outlet out of pectoral spine ( Figs. 5e-g).
Brand new cleithrum regarding P. hemioliopterus does not have rough ornamentation collectively ventral side of “neck,” together with horizontal fat out of “shoulder” terminates rear to the stage out of articular retailer off pectoral spine ( Figs. 5i, j). Zero cleithrum of your Acre Phractocephalus has been seen.
8) Pectoral lower back ornamentation ruled because of the coarse subparallel ridges and you may sulci, and you can relatively partners reticulating ridges and you will pits ( Fig. 5h).
The brand new pectoral spine ornamentation regarding P. hemioliopterus try controlled by reticulating ridges and you can pits ( Fig. 5i). The pectoral lower back of your own Acre Phractocephalus try but really unknown.
Etymology. The new Urumaco types of Phractocephalus is known as for Dr. Pedro Nass inside detection away from their benefits on the systematics and morphology of pimelodid catfishes off South america.
Malfunction. Come across Lundberg et al. (1988) for description regarding neurocranium (MCN.USB 72-85 PB) and extra specifications. The next information is provided by the new holotype and you will recently received specimens.
Neurocranium, dorsal element ( Fig. 3a). Story types of skull everything square, width all over lateral ethmoids comparable to thickness round the sphenotics, and they widths a little less than maximum thickness round the pterotic wings; thickness round the pterotics contains 2.25 minutes inside (45% of) dorsal head length of mesethmoid tip to posterior side of supraoccipital procedure. Epidermis mainly flat however, margins rounded quite downwards and dorsal midline even more curved posteriorly. The bones ornamented which have rough reticulating ridges and you may rounded pits and you will some longitudinally elongate ridges and you will grooves, with the exception of olfactory tablets and you will extremities regarding mesethmoid cornua.
