FIGURE 1. Left: location map of the Central Argentine Precordillera basin, San Juan Province, western Argentina, showing Silurian-Devonian outcrops and fossiliferous localities. Right: the type area of Dalmanitoides drevermanni and D. boehmi at the Loma de los Piojos locality, to the southwest of Jáchal, shown in more detail.

FIGURE 2. Stratigraphic column of the Talacasto Formation at Loma de los Piojos section, where it is most developed. Column shows the stratigraphic position of the studied Dalmanitoides species in Devonian sedimentary succession. Dashed lines represent low abundance, complete lines correspond to most fossiliferous levels. Star shows probable location of type levels of Dalmanitoides drevermanni.

FIGURE 3. Cephala of Dalmanitoides drevermanni (Thomas, 1906). 1, 4, 6-7, 10-11 specimen CEGH-UNC 10499, partial cephalon: 1, internal mould dorsal view, 4, idem lateral view, 7, idem anterolateral dorsal view, 10, idem frontal view, 6, latex mould, dorsal view, arrows point to spiny processes on anterior border, 11, idem frontal view. 2-3, 5, 8, 12 specimen CORD-PZ 8615, partial cephalon: 2, internal mould, dorsal view, 5, idem lateral view, 8, idem anterolateral dorsal view, 12, detail of the anterior doublure and anterior margin, ventral view, 3, latex mould, dorsal view. 9 specimen CEGH-UNC 24304, partial cephalon, internal mould, dorsal view, arrow shows a spine on posterior border. Loma de los Piojos Section, Talacasto Formation, type early Emsian levels, San Juan Province, Argentina. Scale bar equals 5 mm.

FIGURE 4. Articulated specimens of Dalmanitoides drevermanni (Thomas, 1906). 1-6, CEGH-UNC 12738, outstretched articulated specimen, strongly compressed dorso-ventrally: 1, internal mould nearly complete, dorsal view, 2, latex cast, dorsal view, 3, detail of pleural lobes, internal mould, dorsal view, 4, latex cast, dorsolateral view, 5, detail of cephalon internal mould, dorsal view, 6, detail of occipital spine, dorsolateral view. Loma de los Piojos Section, Talacasto Formation, indeterminate levels, probably Pragian levels according to sandy lithology. 7, specimen CEGH-UNC 24309, two thoracic segments showing dorsal spine bases, type early Emsian levels, same section, San Juan Province, Argentina. Scale bar equals 5 mm.

FIGURE 5. Pygidia of Dalmanitoides drevermanni (Thomas,1906). 1-5, specimen CEGH-UNC 24307, partial pygidium, internal mould: 1, dorsal view, 2, lateral view, 3, posterior view, 4, posterodorsolateral view, 5, dorsolateral view. 6-10, 15, specimen CORD-PZ 8608, partial pygidum latex cast, 6, dorsal view, 7, lateral view, 8, posterior view, 9, posterodorsolateral view, 10, dorsolateral view, 15 detail of pleural field. 11-13, specimen CEGH-UNC 24313, partial pygidium latex cast, 11, dorsal view, 12, lateral view, posterior view. 14, specimen CEGH-UNC 24302, partial pygidium, internal mould, posterodorsolateral view. Loma de los Piojos Section, Talacasto Formation, 11-13 Pragian levels, all remaining type early Emsian levels, San Juan Province, Argentina. Scale bar = 5 mm.

FIGURE 6. Cephala of Dalmanitoides drevermanni? (Thomas, 1906). 1, 3-4, 6-9, 12, specimen CEGH-UNC 24318, 1, latex cast of partial cephalon, dorsal view, 3, internal mould, dorsal view, 4, latex cast, anterolateral view, 6, detail of anterior portion of cephalon, internal mould, 7, latex cast, anterolateral view, 8, anterolateral view, 9, lateral view, 12, frontal view. 2, 5, specimen CEGH-UNC 24324, partial cephalon: 2, dorsal view, 5, anterolateral view. 10, specimen CEGH-UNC 24327, latex cast of librigena, lateral view. 11, specimen CEGH-UNC 24324B, latex cast of a dalmanitine-type cheek showing a flat genal spine bearing a continuation of the epiborder furrow along its lower side. La Chilca section, Talacasto Formation, early Emsian levels, San Juan Province, Argentina. Scale bar equals 5 mm.

FIGURE 7. Cephala of Dalmanitoides boehmi (Knod, 1908). 1-4, specimen CEGH-UNC 24429, partial cephalon: 1, internal mould, dorsal view, note left S2 is effaced due to a malformation, 2, idem dorsolateral view, 3, idem anterodorsolateral view, 4, idem frontal view.5-9, specimen CEGH-UNC 24419, partial cephalon: 5, dorsal view, 6, idem lateral view, 7, detail of crenulated anterior margin, and anterior doublure, ventral view, 8, idem anterodorsolateral view, 9, frontal view. 10, specimen CEGH-UNC 24315, partial cephalon, internal mould, dorsal view. 11-12, specimen CEGH-UNC 24412, librigena showing the eye socle and the lateral doublure separated in a nearly sharp angle from the border (in cross section), 12 idem, dorsal view showing facial sutures. 13, specimen CEGH-UNC 24402, cheek showing the epiborder furrow, dorsal view. Loma de los Piojos Section, Talacasto Formation, Pragian levels under the guide horizon of Keidel (1921), San Juan Province, Argentina. Scale bar equals 5 mm.

FIGURE 8. Pygidia of Dalmanitoides boehmi (Knod, 1908). 1-4, specimen CEGH-UNC 24379, internal mould, 1, dorsal view, 2, idem lateral view, 3, idem posterior view, 4, idem posterodorsolateral view. 5-8, specimen CEGH-UNC 24331, internal mould, 5, dorsal view, 6, idem lateral view, 7, posterior view, 8, posterodorsolateral view. 9-12, specimen CEGH-UNC 24374, internal mould, dorsal view. 10, lateral view, 11, detail of mucro, posterolateral view, 12, posterodorsolateral view. 13, specimen CEGH-UNC 24380, partial pygidium, latex cast. 14, specimen CEGH-UNC 24378, partial pygidium, dorsal view, note evenly granulated surface of the carapace and tubercules on posterior pleural bands invading following anterior pleural bands backwards. 15, specimen CEGH-UNC 24377, pygidium with some thoracic segments attached, dorsal view, note tubercles on thoracic axial rings and long (exsag.) thoracic pleural furrows. Loma de los Piojos Section, Talacasto Formation, Pragian levels of the guide horizon of Keidel (1921) and immediately underlying, San Juan Province, Argentina. Scale bar equals= 5 mm.

FIGURE 9. Hypostome of D. boehmi. 1-4, specimen CEGH-UNC 24377, 1, latex cast, ventral view, 2, anteroventrolateral view, 3, detail of denticles on posterior margin, 4, lateral view. Loma de los Piojos Section, Talacasto Formation, Pragian (early Emsian?) levels of the guide horizon of Keidel (1921), preserved in a nodule together with a pygidium, San Juan Province, Argentina. Scale bar equals 5 mm.

FIGURE 10. Dalmanitoides boehmi (Knod, 1908). 1, scanned copy of the original drawing published by Knod (1908, p. 567, figure 21.1). 2, the original holotype specimen collected by Hauthal from the Talacasto Formation, to the southwest of Jáchal, probably Pragian strata, to the west of Loma de los Piojos section, San Juan. Presently housed at University of Freiburg (Institut für Geowissenschaften-Geologie, repository number: 2778), Freiburg, Germany. Probably an internal mould, dorsal view. Note that the original fossil is either idealized in the drawing or suffered damage after it was published. Scale bar equals 5 mm.

FIGURE 11. Dalmanitoides accola (Clarke, 1913). 1, specimen NYSM 12069 , cephalon, dorsal view, note lack of crenulation on anterior border anterolaterally. 2, specimen NYSM 12072, cephalon, internal mould, dorsal view. 3, specimen NYSM 12077, cephalon, anterolateral view, note the rounded median projection of the anterior border. 4, specimen NYSM 17262 , skeletal associated parts (moult ensemble?), dorsal view, note the irregular distribution of coarse to spinose tubercles on pygidial axial rings. 5, specimen NYSM 17304, nearly articulated specimen, dorsal view. 6, specimen NYSM 17466, pygidium, internal mould, dorsal view. 7, specimen NYSM 17467, external mould of pygidium, dorsal view. Lower Devonian, Ponta Grossa Formation, Paraná, Brazil. Scale bar equals 5 mm.