FIGURE 1. Specimen IGM 11532, Armigatus brevissimus from the Cenomanian shallow marine deposits of Hekel, Lebanon, coated with magnesium smoke.
FIGURE 2. Map of the Tlayúa quarry near Tepexi de Rodríguez, Puebla, central Mexico, and the stratigraphical column of the upper part of this site, including the magnetostratigraphy correspondence with the middle-late Albian age, and the distribution of fossils studied in this work (modified from Kashiyama et al., 2004, figure 3; Alvarado-Ortega 2005, figure 2.4; Benammi et al., 2006, figure 5).
FIGURE 3. IGM 11536, holotype of Armigatus carrenoae sp. nov. from the Albian deposits of Tlayúa lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico. A, photograph of the complete specimen under UV light. B, idealized drawing of the same specimen.
FIGURE 4. Paratypes of Armigatus carrenoae sp. nov. from Albian deposits of Tlayúa lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico, photographed under UV light. A, IGM 11537. B, IGM 11538. C, IGM 11540.
FIGURE 5. Head of Armigatus carrenoae sp. nov. from the Albian deposits of Tlayúa lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico. A, Closeup of IGM 11538, coated with magnesium smoke and photographed under white light. B, idealized and simplified drawing of A. Abbreviations: aa, anguloarticular; ao, antorbital; br, branchiostegal ray; cl, cleithrum; ddml depression for the dento-maxillar ligament; den, dentary; dsph, dermosphenotic; ect, ectopterygoid; ent, endopterygoid; epo, epioccipital; epn, epineurals; ext, extrascapular; fr, frontal; hm, hyomandibular; io, infraorbital; iop, interopercle; le, lateral ethmoid; mes, mesethmoid; mp, metapterygoid; mx, maxilla; na, nasal; naac, neural arches + spines of abdominal centrum; op, opercle; os, orbitosphenoid; os, orbitosphenoid; pa, parietal; pal, palatine; pcl, postcleithrum; pd, predorsal; pfr, pectoral fin ray; pop, preopercle; prvas, prepelvic abdominal scutes; psp, parasphenoid; pto, pterotic; pts, pterosphenoid; ptt, posttemporal; q, quadrate; r, rib; rar, retroarticular; sc, sclerotic; scl, supracleithrum; smx, supramaxilla; soc, supraoccipital; sop, subopercle; suo, supraorbital; dark arrow shows the basipterygoid process of the parasphenoid bone; (l) and (r) indicates the left and right side.
FIGURE 6. Part of the pectoral girdle, lower jaw, branchial arch, and branchiostegal rays of Armigatus carrenoae sp. nov. from the Albian deposits of the Tlayúa lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico. A, closeup of the head of the paratype IGM 11537 under UV light. B, idealized and simplified drawing based on A. Abbreviations: aa, anguloarticular; ac, anterior ceratohyal; bh, basihyal; br, branchiostegal ray; cl, cleithrum; cor, coracoid; ddml depression for the dento-maxillar ligament; den, dentary; dh, dorsal hypohyal; iop, interopercle; pc, posterior ceratohyal; pcl, postcleithrum; pfr, pectoral fin ray; prvas, prepelvic abdominal scutes; q, quadrate; rar, retroarticular; rad, radial; sca, scapula; sop, subopercle; sy, symplectic; uh, urohyal; vh, ventral hypohyal.
FIGURE 7. Closeup of the postorbital region of IGM 11539 showing the osteoglossid-like tooth patch on the parasphenoid bone (black arrows). Abbreviations: hm, hyomandibular; mtp, metapterygoid; pop, preopercle; psp, parasphenoid.
FIGURE 8. Idealized and simplified drawing of the trunk and pelvic, anal, and dorsal fins of IGM 11536, holotype Armigatus carrenoae sp, nov. from the Albian deposits of Tlayúa lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico (based on Figure 3). Abbreviations: afr, anal fin ray; afs, anal fin stay; appt, anal proximal pterygiophore; dfr, dorsal fin ray; dfs, dorsal fin stay; dppt, proximal pterygiophores of dorsal fin; epl, epipleural; epn, epineural; hapu, hemal arch and spine of preural centrum; naac, neural arch of abdominal centrum; napu, neural arch and spine of preural centrum; napu4, preural centrum 4 with double neural spine; pd, predorsal bone; php, parhypural; prvas, prepelvic abdominal scute; ptvas, postpelvic abdominal scute; pvfr, pelvic fin ray; r, rib; u, ural centrum; numbers under centra indicate their position along the vertebral column.
FIGURE 9. The caudal skeleton of Armigatus carrenoae sp. nov. from the Tlayúa Lagerstätte, near Tepexi de Rodríguez, Puebla, Mexico. A, closeup of the caudal skeleton of IGM 11538 coated with magnesium smoke. B, idealized and simplified drawing of A. Abbreviations: afr, anal fin ray; cs, caudal scute; ep, epural; epl, epipleural; epn, epineural; hapu, hemal arch of preural centrum; hy, hypural; napu, neural arch of preural centrum; nau, neural arch of ural centrum; php, parhypural; prl, branched and segmented caudal fin ray of the lower lobe; prlI, unbranched caudal principal fin ray of the lower lobe; pru, branched and segmented caudal fin ray of the upper lobe; pruI, unbranched caudal principal fin ray of the upper lobe; pu, preural centrum; u, ural centrum; un, uroneural.
FIGURE 10. Predorsal scutes series of Armigatus carrenoae sp. nov. from Tlayúa. A, closeup of the predorsal region of IGM 11536 (inverted for comparative purposes). B, closeup of predorsal region of IGM 11537. C, idealized drawing of B. Abbreviations: afr, anal fin ray; pd, predorsal bone; pds, predorsal scutes; dppt, dorsal proximal pterygiophore; upds, unmodified predorsal scales.
FIGURE 11. Phylogenetic hypotheses of Ellimmichthyiformes that show the different positions of Armigatus (dark lines) and members of this order (dark circle) and Clupeiformes (white square).
FIGURE 12. Dorsal region of Armigatus brevissimus. A, closeup of the specimen IGM 11532 from the Cenomanian shallow marine deposits of Hekel, Lebanon, under white light. B, idealized and simplified drawing of predorsal scutes and near bones based on A. Abbreviations: afr, anal fin ray; pd, predorsal bone; pds, predorsal scutes; dppt, dorsal proximal pterygiophore; upds, unmodified predorsal scales.
FIGURE 13. Paleobiographical distribution and diversity of predorsal scutes of Armigatus. Abbreviations in the predorsal scute formula: C, complete predorsal scute series; I, incomplete predorsal scute series; the number of predorsal scutes in each species is shown in front of the draws; draws show the change in the shape of the scutes along the predorsal observed in species; light arrows point to posterior scutes; dark arrows show the hypothetic intraspecific change of the predorsal scutes.
