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. 2006 Nov 21;274(1609):489–498. doi: 10.1098/rspb.2006.3749

Figure 2.

Figure 2

Strict consensus of the 116 shortest trees from the parsimony analysis of the morphological dataset of fossil and Recent Actinopterygii. Bold lines indicate crown-group Neopterygii. (a) Discoserra pectinodon Lund (2000), from the Mississippian (Serpukhovian) of Montana, USA. Dermal skull of CM (Carnegie Museum) 35211B in lateral view, anterior to left. Standard neopterygian apomorphies include the presence of an interopercular bone (iop), a supraorbital (spo), the shape and separation of the maxilla (mx) from the preopercular (pop), and the presence of a coronoid process (cpr) on the lower jaw. (b) Discoserra pectinodon (CM 41009A): caudal fin, external view with scales showing row-reversal at the meeting of peduncle and flank squamation. Neopterygian apomorphies include an abbreviated heterocercal shape (cf. modern lepisosteids), widely separated fin rays and the posterior terminus of lateral-line canal (tlln) directed onto fin, rather than extending posterio-dorsally along vestigial caudal lobe of the main body axis. Further details of braincase, hyoid arch, axial and caudal endoskeleton are provided in the electronic supplementary material. (c) Brachydegma caelatum Dunkle (1939), a basal stem-group halecomorph from the Early Permian (Artkinsian) of Texas, USA. Skull and pectoral region of MCZ (Museum of Comparative Zoology, Harvard University) 6503 in lateral view, anterior to right. (d) Brachydegma caelatum, left antorbital, showing a fractured anterior process (antpr) and in-filled sensory canal. (e) Brachydegma caelatum, left maxilla in (upper) dorsal and (lower) lateral views. Apomorphies shared with Amia and its closest fossil relatives include large median gular (mgu), maxilla (mx) with indented rear margin and horizontal median shelf or process (mpr), and antorbital (ao) with tapering anterior process (antpr). Neopterygian apomorphies include the presence of supraorbital (spo), accessory postcleithrum (apcl) and coronoid process (cpr) on the lower jaw. antpr, anterior process; ao, antorbital; aplcl, accessory postcleithrum; cl, cleithrum; cpr, coronoid process; dpt, dermopterotic; dsp, dermosphenotic; fb, basal fulcra; frf, fringing fulcra; hp, hypurals; io, infraorbital; iop, interoperculum; la, lachrymal; lgu, lateral gular; lpt, lepidotrichia; mgu, median gular; mpr, mesial process; mx, maxilla; op, opercular; pmx, premaxilla; pop, preoperculum; qj, quadratojugal; qu, quadrate; ro, rostral; sbo, suborbital; scb?, possible scale-bone; scl, supracleithrum; smb, smooth unornamented band; sop, subopercular; spo, supraorbital; tlln, terminal lateral-line scale.