When you look at the progressive P. hemioliopterus the fresh related central area of the skull roof is almost completely ornamented from the reticulating ridges and you may pits, which have partners or no elongate, parallel ridges and you may sulci ( Fig. 4a). Regarding the Acre Phractocephalus this new main region of the skull rooftop has some elongate ridges and sulci plus reticulating ridges and pits.
The new horizontal ethmoid bone of P
2) Mesethmoid bone extremely wide ( Dining table step one); dorsal facial skin widely ornamented; anterior boundary hardly emarginate so you’re able to lightly circular ( Fig. 3a).
The brand new mesethmoid bones out of P. hemioliopterus is relatively slim-necked, quicker commonly ornamented simply centrally and posteriorly, and its anterior line is emarginate or shallowly concave ( Fig. 4a). nassi.
3) Lateral ethmoid maybe not continuously projecting anteriorly over palatine condyle; its horizontal margin convex and you will removing orbital notch on the margin regarding head rooftop ( Fig. 3a).
hemioliopterus is also not excessive projecting anteriorly over the olfactory area otherwise palatine condyle; however it is concave sideways, possesses a properly defined orbital sulcus to your margin out of head roof ( Fig. 4a). Regarding Acre Phractocephalus the new lateral ethmoid tactics far anteriorly more this new olfactory part and palatine condyle; it’s convex laterally, reducing the new orbital sulcus on the margin from head roof.
Progressive P. hemioliopterus have an open anterior cranial fontanelle inside a prominent depression away from epiphyseal region ( Fig. 4a), whereas about Acre Phractocephalus the new fontanelle and you can anxiety of epiphyseal region lack.
5) Supraoccipital procedure that have round horizontal and you can posterolateral margins, posterior margin concave medially; supraoccipital processes a lot of time, inside the dorsal examine completely covering modified prior vertebrae regarding Weberian cutting-edge ( Fig. 3a).
The new opercle P
In modern P. hemioliopterus this new supraoccipital processes is quick, in dorsal consider perhaps not completely level modified vertebrae out-of Weberian complex; it offers angular horizontal and you can posterolateral margins, and its rear margin is irregular to concave medially and you will results a deep unornamented expansion less than anterior nuchal plate ( Fig. 4a). On Acre Phractocephalus the newest supraoccipital process are enough time, totally within the Weberian state-of-the-art; the procedure provides angular sides and you may upright lateral margins, as well as posterior ented expansion lower than anterior nuchal dish.
hemioliopterus is incompletely wrapped in reticulating ridges and you can pits ( Fig. 5c). The opercle try thus far unfamiliar from the Acre Phractocephalus.
7) Cleithrum having coarse ornamentation stretching along ventral border forming outward pouch otherwise «shoulder» horizontal to spine articulation; pouch away from «shoulder» terminating posteriorly, in accordance with termination from articular socket from pectoral lower back ( Figs. 5e-g).
The new cleithrum out-of P. hemioliopterus does not have coarse ornamentation together ventral side of «neck,» together with horizontal fat regarding «shoulder» terminates posterior to the level out of articular retailer away from pectoral spine ( Figs. 5i, j). No cleithrum of one’s Acre Phractocephalus has been found.
8) Pectoral lower back ornamentation reigned over of the coarse subparallel ridges and sulci, and you will apparently partners reticulating ridges and you can pits ( Fig. 5h).
New pectoral back ornamentation out-of P. hemioliopterus was dominated because of the reticulating ridges and you can pits ( Fig. 5i). The fresh new pectoral spine of the Acre Phractocephalus are yet unfamiliar.
Etymology. This new Urumaco types of Phractocephalus is named getting Dr. Pedro Nass inside the identification of their efforts to the systematics and you can morphology from pimelodid catfishes out-of South america.
Breakdown. See Lundberg et al. (1988) having breakdown regarding neurocranium (MCN.USB 72-85 PB) and extra measurements. The following data is available with the latest holotype and recently received specimens.
Neurocranium, dorsal factor ( Fig. 3a). Information particular head whenever rectangular, thickness round the horizontal ethmoids equivalent to thickness across the sphenotics, that widths a bit less than restriction depth around the pterotic wings; depth all over pterotics consisted of 2.twenty-five times in (45% of) dorsal skull duration from mesethmoid idea in order to rear edge of supraoccipital techniques. Facial skin mostly flat but margins curved quite downward and dorsal midline all the more arched posteriorly. All skeleton ornamented with coarse reticulating ridges and you can game pits and you can particular longitudinally elongate ridges and you will grooves, apart from olfactory medicine and extremities away Dating Web Sitelerinde Con Artist from mesethmoid cornua.