A new madtsoiid snake from the Paleogene of South America (northwestern Argentina), based on an articulated postcranial skeleton

Figures & data

FIGURE 1. Detail of the study area (square in map of Argentina) and location of Mina Aguilar (star).

TABLE 1. Vertebral measurements (see Fig. S11) in mm of selected vertebrae from PVL 4714. Abbreviations: APV, anterior precloacal vertebra; CL, centrum length; CNW, condyle width; COW; cotyle width; DW, width across diapophyses; MPV, middle precloacal vertebrae; NAW, neural arch width; NSH, neural spine height; POW, width across postzygapophyses; PR-PO, length from the anterior edge of the prezygapophyseal facet to the posterior edge of the postzygapophyseal facet; PRW, width across prezygapophyses; TVH, total vertebral height; ZSH, zygosphene height; ZSW, zygosphene width.

	38th (APV)	39th (APV)	45th (MPV)	46th (MPV)
CL	12.40*	14.44	15.50	—
NAW	16.25	16.25	18.80	18.40
PRW	—	21.56	25.98	—
POW	22.14	22.80	26.07	25.41
ZSW	12.14*	—	11.42*	—
ZSH	04.51	—	05.35	—
COW	07.02	—	07.67	06.80
CNW	—	05.67	08.07	—
NSH	—	03.93	06.04	03.11*
PR-PO	17.13	18.07	20.06	19.91
DW	18.76*	18.94	19.27	21.81
TVH	—	25.31	24.05	22.70*

*Estimated because of breakage, erosion, or when articulated.

FIGURE 2. Powellophis andina gen. et sp. nov. (PVL 4714). A, cast of the original specimen as collected from the field; B, correspondence of each of the sectioned slabs after preparation.

FIGURE 3. PVL 4714-3, anterior precloacal vertebrae (38th and 39th) and interpretative drawing. A, anterior view; B, posterior view; C, left lateral view; D, dorsal view, E, ventral view. Abbreviations: con, condyle; cot, cotyle; hp, hypophysis; izc, interzygapophyseal constriction; izr, interzygapophyseal ridge; lc, laminar crest; lf, lateral foramen; naf, neural arch fossa; nc, neural canal; ns, neural spine; pcf, paracotylar foramen; pzf, parazygantral foramen; prz, prezygapophysis; scf, subcentral foramen; scr, subcentral ridge; syn, synapophysis; zp, zygosphene; zt, zygantrum.

FIGURE 4. PVL 4714-4, middle precloacal vertebra (49th) and interpretative drawing. A, anterior view; B, posterior view; C, left lateral view; D, dorsal view, E, ventral view. Abbreviations: con, condyle; cot, cotyle; hk, hemal keel; izc; interzygapophyseal constriction; izr, interzygapophyseal ridge; lc, laminar crest; lf, lateral foramen; naf, neural arch fossa; nc, neural canal; ns, neural spine; pcf, paracotylar foramen; pe, posterior embayment; pzf, parazygantral foramen; prz, prezygapophysis; ptz, postzygapophysis; scf, subcentral foramen; scr, subcentral ridge; syn, synapophysis; zp, zygosphene; zt, zygantrum.

FIGURE 5. PVL 4714-4, middle precloacal vertebra (50th) and articulated left rib fragment. A, anterior view; B, posterior view; C, right lateral view; D, dorsal view, E, ventral view. Abbreviations: r, rib fragment; zp, zygosphene from succeeding vertebra.

FIGURE 6. PVL 4714-5, middle precloacal vertebrae and ribs (51st to 57th). A, dorsal view. B, ventral view. Numbers indicate position in the column.

FIGURE 7. Phylogenetic relationships of Powellophis andina gen. et sp. nov. Strict consensus of six most parsimonious trees of 810 steps each. Numbers above and below branches indicate Bremer support and jackknife absolute values, respectively. Crown group Serpentes is shown as a solid triangle, for complete tree see Fig. S10.