Total evidence phylogeny from Bayesian analysis of molecular and morphological data, from Wood et al. (2015). Outgroups not shown and with the morphospecies names changed to the new species names from the current study. Posterior probabilities are as follows, greater than or equal to: (*) 0.90; (**) 0.95; (***) 0.99.

Diagram showing several measured morphological traits, lateral view of archaeid habitus. 1 carapace length 2 carapace tilt height (CtH) 3 carapace constriction 4 “neck” length 5 carapace tilt angle 6 “head” length 7 chelicerae length 8 cheliceral seta length.

Eriauchenius andriamanelo sp. n. A male (CASENT9004508) habitus, lateral view. B, L female (CASENT9003265) internal genitalia, arrow showing sclerotized T-shaped projection: B dorsal view L posterior view D–F male right pedipalpal bulb (CASENT9010070), image reversed C, G–I left pedipalpal bulb (CASENT9017991) J–K left pedipalpal bulb (CASENT9002367) C median apophysis, apical view D, G, J prolateral view E, H, K ventral view F, I retrolateral view K arrows showing the two portions of the divided conductor tip. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius andrianampoinimerina sp. n. A female (CASENT9018902) habitus, lateral view, image reversed B female (CASENT9015417) internal genitalia, dorsal view C–F male right pedipalpal bulb (CASENT9015371), image reversed G–I left pedipalpal bulb (CASENT9015518) C median apophysis close-up, apical view D, G prolateral view H, K ventral view I, L retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius rafohy sp. n. A male (CASENT9015039) habitus, lateral view, image reversed B female (CASENT9006503) internal genitalia, dorsal view D–F, L male right pedipalpal bulb (CASENT9004087), image reversed G–K left pedipalpal bulb (CASENT9015039) C median apophysis variation, apical view (CASENT9004087 & CASENT9015039) D, G, J prolateral view E, H, K ventral view F, I retrolateral view L close-up, ventral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius ranavalona sp. n. A male (holotype, CASENT9010047) habitus, lateral view, image reversed B female (USNMENT01377248) internal genitalia, dorsal view C–D abdomen, showing color pattern (USNMENT01377246) C lateral view D posterior view E–G male right pedipalpal bulb (holotype, CASENT9010047), image reversed H–J left pedipalpal bulb (CASENT9010042) E, H prolateral view F, I ventral view G, J retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius rangita sp. n. A male (CASENT9018159) habitus, lateral view B, L female (CASENT9018159) internal genitalia B dorsal view L posterior view, arrow showing membranous projection on bursa D–F, J–K male right pedipalpal bulb (CASENT9018251) image reversed G–I left pedipalpal bulb (CASENT9018159) C median apophysis variation, apical view (CASENT9018159 & CASENT9010053, holotype) D, G prolateral view E, H ventral view F, I retrolateral view J close up, prolateral view K close-up, ventral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius workmani Pickard-Cambridge, 1881. A male (CASENT9010050) habitus, lateral view B female (CASENT9010045) internal genitalia, dorsal view D–F, L male right pedipalpal bulb (CASENT9010058) image reversed G–I left pedipalpal bulb (CASENT9003490) J–K left pedipalpal bulb (CASENT9010056) C median apophysis variation, apical view D, G, J prolateral view E, H, K ventral view, arrow showing the large bump on the anterior side F, I retrolateral view K close-up, ventral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius fisheri (Lotz, 2003). A male (CASENT9018939) habitus, lateral view, image reversed B–C female (holotype, CASENT9012340) internal genitalia B dorsal view C anterior view D–L male pedipalpal bulbs (CASENT9018939) D–F, L right bulb, image reversed G–K left bulb D, G, J prolateral view E, H, K ventral view F, I retrolateral view K close-up, ventral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius goodmani sp. n. A male (holotype, Field Museum) habitus, lateral view B–C female (Field Museum) genitalia B dorsal view C ventral view D–F male left pedipalpal bulb (holotype, Field Museum) D prolateral view E ventral view F retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius harveyi sp. n. A male (holotype, CASENT9012110) habitus, lateral view, image reversed B–C female (CASENT9012342) genitalia B dorsal view C ventral view D–K male pedipalpal bulbs (CASENT9012109) D–F right bulb, image reversed G–K left bulb D, G, J prolateral view E, H, K ventral view F, I retrolateral view L male (CASENT9012109), arrow showing the long cheliceral seta that projects perpendicularly from the chelieral cuticle, lateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius wunderlichi sp. n. A female (CASENT9062648) habitus, lateral view, image reversed B–C female (CASENT9062648) genitalia B dorsal view, arrow showing the large bulge on the posterior bar C ventral view D–F male left pedipalpal bulb (holotype, CASENT9062702) D prolateral view E ventral view F retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius bourgini (Millot, 1948). A female (CASENT9001207) habitus, lateral view, image reversed B–C female (CASENT9001207) internal genitalia B dorsal view C anterior view, arrows showing two sclerotized invaginations on the bursa D–K male pedipalpal bulbs (CASENT9001207), D–F, K right bulb, image reversed G–J left bulb D, G, J prolateral view E, H ventral view F, I retrolateral view K apical view L coxae I male (CASENT9001207), ventral view, arrows showing the pointed extensions on coxae I. Scale bars: 1 mm (A); 0.125 mm (B); 0.25 mm (D).

Eriauchenius lukemacaulayi sp. n. A female (USNMENT01377191) habitus, lateral view, image reversed B–C, F female internal genitalia (USNMENT01377192) B posterior view C anterior view F dorsal view, arrow showing the rounded posterior elongation on the FSGP that curves dorsally. D–E, G–I male pedipalpal bulbs (holotype, USNMENT01377191), right bulb, image reversed D, G prolateral view E, I retrolateral view H ventral view, arrow showing the large bulge that occurs after the constriction in the conductor. Asterisk (*) showing the narrow, lateral process on the conductor. Scale bars: 1 mm (A); 0.25 mm (B); 0.5 mm (D).

Eriauchenius mahariraensis (Lotz, 2003). A male (USNMENT01377173) habitus, lateral view, image reversed B–C female (holotype, MCZ) internal genitalia B dorsal view C anterior view, arrow showing the small sclerotized piece next to the poreplates D–K male pedipalpal bulbs (USNMENT01377173) D–F right bulb, image reversed G–L left bulb: D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Scale bars: 1 mm (A); 0.125 mm (B, D)..

Eriauchenius milajaneae sp. n. A female (holotype, CASENT9009881) habitus, lateral view B–C female (holotype, CASENT9009881) internal genitalia: B dorsal view, arrow showing broad, rectangular, posterior elongation on the FSGPC anterior view. Scale bars: 1 mm (A); 0.25 mm (B).

Eriauchenius milloti sp. n. A male (USNMENT01377189) habitus, lateral view B–C female (USNMENT01377189) internal genitalia B dorsal view C anterior view D–I male pedipalpal bulbs D–F right bulb, image reversed, (USNMENT01377189) G–I left bulb (USNMENT01377189) J–K left bulb (CASENT9015862) D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Asterisk (*) showing the narrow, small process on the conductor. Arrow showing constriction in the conductor. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius pauliani (Legendre, 1970), holotype, MNHN. A–B male A habitus, lateral view, image reversed B anterior view C–H male left pedipalpal bulb C, F prolateral view D, G ventral view, arrow showing the broken tip of the embolus in the left pedipalp E, H retrolateral view I male right pedipalpal bulb, embolus tip close-up showing the unbroken embolus, image reversed. Scale bars: 1 mm (A); 0.25 mm (C).

Eriauchenius ratsirarsoni Lotz, 2003. A male (USNMENT01377174) habitus, lateral view, image reversed B–C female (CASENT9028378) internal genitalia B posterior-dorsal view, arrows showing the lateral bulges on the FSGPC anterior view D–L male pedipalpal bulbs D–F right bulb (USNMENT01377174), image reversed G–J left bulb (USNMENT01377174) K–L left bulb (CASENT9062876) D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view J arrow showing conductor variation, with a tapering tip K, L arrow showing conductor with a blunt tip. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius rixi sp. n. A male (holotype, CASENT9012013) habitus, lateral view, image reversed B–C female (CASENT9012346) internal genitalia B dorsal view, arrow showing the FSGP narrow posterior elongation C anterior view D–L male pedipalpal bulbs (holotype, CASENT9012013) D–F right bulb, image reversed G–L left bulb, arrow showing the sharp process on the tegulum base D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius sama sp. n. A male (holotype, CASENT9012014) habitus, lateral view, image reversed B–C female (CASENT9012341) internal genitalia: B dorsal view C anterior view D–L male pedipalpal bulbs (holotype, CASENT9012014), arrow showing the change in direction in the curve of the conductor tip D–F right bulb, image reversed G–L left bulb D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius zirafy sp. n. A male (CASENT9015571) habitus, lateral view B–C female (USNMENT01377190) internal genitalia B dorsal view C anterior view, arrows showing two sclerotized invaginations on the bursa D–L male pedipalpal bulbs (CASENT9015571), black arrow showing the small bumps on the conductor base D–F, L right bulb, image reversed G–K left bulb: D, G, J prolateral view E, H ventral view F, I, K retrolateral view L close-up of small bumps on conductor base, retrolateral view, white arrow showing small pores. Scale bars: 1 mm (A); 0.125 mm (B); 0.25 mm (E).

Madagascarchaea fohy sp. n. A male (holotype, CASENT9015766) habitus, lateral view B female (CASENT9015766) internal genitalia, dorsal view C–L male pedipalpal bulbs (holotype, CASENT9015766) D–F right bulb, image reversed C, G–L left bulb C cymbium close-up, dorsal view, arrow showing the retrolateral cymbium protrusion that has setae D, G, J prolateral view, arrow showing rod-like piece on embolus E, H, K ventral view, arrow showing rod-like piece on embolus F, I, L retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Eriauchenius legendrei (Platnick, 1991). A male (USNMENT01377217) habitus, lateral view B female (CASENT9012333) internal genitalia, dorsal view. C–I male pedipalpal bulbs D–F left bulb (CASENT9012333) C left bulb (CASENT9010074) G–I left bulb (USNMENT01377217): C cymbium close-up, dorsal view, arrow showing the small retrolateral cymbium protrusion that lacks setae D, G prolateral view E, H ventral view F, I retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Madagascarchaea rabesahala sp. n. A male (holotype, CASENT9004011) habitus, lateral view, image reversed B female (CASENT9004086) internal genitalia, dorsal view C–I male pedipalpal bulbs D–F right bulb (CASENT9004086), image reversed C, G–I left bulb (CASENT9004086): C cymbium close-up, dorsal view, arrow showing the absence of a retrolateral cymbium protrusion D, G prolateral view E, H ventral view F, I retrolateral view. Scale bars: 1 mm (A); 0.25 mm (B, D).

Madagascarchaea jeanneli (Millot, 1948). A male (CASENT9004085) habitus, lateral view, image reversed B–C female (CASENT9012336) internal genitalia B dorsal view C anterior view. D–L male pedipalpal bulbs D–I left bulb (CASENT9004085) J–L left bulb (CASENT9005233): D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Scale bars: 1 mm (A); 0.125 mm (B, D).

Madagascarchaea lotzi sp. n. A male (CASENT9018921) habitus, lateral view, arrow showing posterior invagination of abdomen B–C female (CASENT9012008) internal genitalia B dorsal view C anterior view D–L male pedipalpal bulbs D–F right bulb (CASENT9012004), image reversed, G–L left bulb (CASENT9012330) D, G, J prolateral view E, H, K ventral view F, I, L retrolateral view. Scale bars: 1 mm (A); 0.125 mm (B, D).

Madagascarchaea moramora sp. n. A male (holotype, USNMENT01377197) habitus, lateral view, image reversed, arrow showing abdomen posterior is straight. B–C female (USNMENT01377198) internal genitalia B dorsal view C anterior view D–I male pedipalpal bulbs (holotype, USNMENT01377197): D–F left bulb, G–I right bulb, expanded, image reversed D, G prolateral view E, H ventral view; F, I retrolateral view. Scale bars: 1 mm (A); 0.125 mm (B, D).

Distribution map for Eriauchenius species.

Distribution map for Eriauchenius species.

Distribution map for Eriauchenius species.

Distribution map for Eriauchenius species. ** The distribution for E. pauliani is an approximation as the holotype does not have latitude/longitude data.

Distribution map for Madagascarchaea species.

Distribution map for Madagascarchaea species.