Only a small fraction of the external surfaces of the supraoccipital, prootic
and exoccipital-opisthotic can be seen in dorsolateral view.
In the chondrocranium this is observed in the occipital and supraoccipital region; the prootic
, otoccipital (opisthotic-exoccipital), basioccipital and basisphenoid are present.
However, the parabasisphenoid is less extended vertically, and the prootic
has separate foramina for branches V1 and V2-3 of the trigeminal nerve (Fig.
a, angular; art, articular; bo, basioccipital; d, dentary; ect, ectopterygoid; f, frontal; j, jugal; l, lacrimal; mcg, meckelian groove; mx, maxilla; n, nasal; op, opisthotic; p, parietal; pal, palatine; pf, postfrontal; pmx, premaxilla; po, postorbital; pp, postparietal; pro, prootic
; prf, prefrontal; pbs, parabasisphenoid; pt, pterygoid; q, quadrate, qj, quadratojugal; so, supraoccipital; sp, splenial; sq, squamosal; st, supratemporal; sa, surangular; ta, tabular; v, vomer
The subsquamosal foramen is anteroposteriorly elongated; therefore, a large area (relative to other species, see below) of the petrosal bone (including the sulcus of the prootic
sinus) is exposed (Fig.
Anterior portion of parasphenoid covering postero dorsal surface of vomer; posterior portion of parasphenoid in contact with prootic
skull bones, otoliths, jaws, prootic
bones of clupeids, teeth and opercula of bony fishes, toothplates of hagfish, and cephalopod beaks and pens) were separated, identified, weighed, and original length measurements were estimated indirectly (standard length for fishes and mantle length for cephalopods).
and/or pterotic bulla lodging diverticulum of swimbladder.
Membrane attached posteriorly to prootic
Anterior supraorbital margins of frontoparietals barely upturned, forming ah indistinct crest; posterior supraorbital margin somewhat upturned; frontoparietals extending over dorsal area of prootic
to level of epiotic eminence; anterior arm of squamosal extending about half distance to maxillary.
3); one pair of slender uroneurals; three epurals; a free parhypural; three thin supraneurals, generally straight; two supernumerary spines on first dorsal pterygiophore; no procumbent spines (spurs); thin Y-shaped basisphenoid, free from parasphenoid and prootics
; neurocranium with frontal tabs similar to Vincentia Castelnau, 1872 (Fraser 1972: pl 31); supramaxilla absent; posttemporal smooth or with 1-3 small serrae on posterior margin; preopercle with 2-3 small, widely spaced serrae near angle, ridge smooth; infraorbitals smooth; infraorbital shelf present on third bone; ring of scleral cartilage, no ossification present; 7 branchiostegals; ceratohyal notched, suture smooth with epihyal; urohyal with short anterior process.