Systematics, morphology and ecology of rails (Aves: Rallidae) of the Mascarene Islands, with one new species Author Hume, Julian Pender text Zootaxa 2019 2019-07-03 4626 1 1 107 journal article 26212 10.11646/zootaxa.4626.1.1 29c4832f-9970-4c9c-9bcb-2564407ac481 1175-5326 3335513 6CC12BAF-968F-4BDE-9315-340AF12A76EC Genus Erythromachus Milne-Edwards, 1874 Erythromachus Milne-Edwards 1874 , p.6 , pls.11–12. Type by monotypy: E. leguati Milne-Edwards Etymology: From Greek eruthros = red, and makhç = battle, combat, in reference to the rail’s aggression shown towards red cloth. Revised Diagnosis: Erythromachus differs from other Mascarene genera by the following characters: Cranium ( Fig. 6 , 22 ): cranium medium-sized; in lateral view, dorso-ventrally compressed; small fonticuli orbitocraniales; large foramen n. optici; processus postorbitalis short and triangular; fossae temporales shallow. Rostrum ( Fig. 6 , 22 ): os premaxillare long, os nasale narrow, and total length nearly 60% longer than cranium length; in lateral view, shallow; narial opening extremely long, extending for 66% the length of the rostrum; foramina neurovascularia present, not extending to rostral edge of narial opening; os nasale narrow; in ventral view, deep, wide sulcus. Mandible ( Fig. 6 ): rostrum mandibulae long and narrow terminating in a sharp point, length symphysis approximately 65% of cranium length; in dorsal view, processus mandibulae medialis indistinct; processus retroarticularis small; sulcus on crista intercotylaris deeply excavated; cotyla lateralis weakly U-shaped; os dentale long, narrow and terminating in a pointed tip; large foramina neurovascularia, deeply set and running almost to a deep sulcus situated in centre of mandible. Scapula ( Fig. 7 ): small and narrow; in lateral view, margo dorsalis distinct; facies articularis humeralis shallow; acromion blunt, rounded and directed dorsad; tuberculum coracoideum indistinct. Coracoid ( Fig. 8 ): short but shaft wide; in dorsal aspect, cotyla scapularis deep, oval-shaped; large foramen n. supracoracoidei sternal to processus procoracoideus; impressio m. sternocoracoidei deeply excavated. Sternum ( Fig. 9 ): small; processus craniolateralis narrow, directed laterad; in dorsal aspect; tuberculum labri externi indistinct; foramen pneumaticum on midline shallow; in ventral view; spina externa variable, reduced or more distinct and square-shaped; in lateral view, carina sterni extremely reduced; apex carinae directed ventrad. Humerus ( Fig. 10 ): extremely reduced, shaft curved dorsoventrally; in caudal aspect, incisura capitis deeply excavated; fossa pneumotricipitalis shallow; in cranial view, crista bicipitalis, short, square-shaped; fossa m. brachialis shallowly excavated. Radius ( Fig. 11 ): short; sulcus tendinosa deep extending proximad approximately ¼ of total length radius length; facies articularis radiocarpalis deflected ventrally; in ventral aspect, depressio ligamentosa deeply excavated. Ulna ( Fig. 12 , 22 ): short and strongly arched dorso-ventrally proximally; tuberculum ligamentosa collateralis prominent; in caudal aspect, olecranon indistinct; processus cotylaris dorsalis short. Carpometacarpus ( Fig. 22 ): in dorsal aspect, processus extensorius short and rounded; os metacarpale majus robust; os metacarpale minus weakly arched creating narrow spatium intermetacarpale; proximal synostosis long. Pelvis ( Fig. 14 , 22 ): in dorsal view, ala preacetabularis weakly expanded laterally; in lateral view, foramen ilioischiadicum is equal or slightly larger than foramen acetabuli; canalis iliosynsacralis extend to distal edge of foramen ilioischiadicum. Femur ( Fig. 15 , 22 ): extremely robust; in cranial view, shaft curved medially and directed caudally at the proximal end; crista trochanteris strongly deflected mediad; in medial aspect, shaft strongly arched dorsally; in caudal aspect, condylus medialis larger than condylus lateralis. Tibiotarsus ( Fig. 15 , 22 ): short, but robust; sulcus extensorius shallow and restricted proximally; canalis extensorius circular, less oval; pons supratendineus arched. Fibula : short and robust; in dorsal view, caput fibulae narrow and weakly grooved caudally; tuberculum m. iliofibularis pronounced and excavated cranially. Tarsometatarsus ( Fig. 15 ): short, but extremely robust; in dorsal aspect, trochleae metatarsorum distinctly splayed, especially trochlea metatarsi II; metatarsi II directed slightly dorsad; presence of an ossified bridge connecting retinaculi extensorii individually variable; in plantar aspect, crista medialis hypotarsi central, not deflected laterally; in plantar aspect, surface area of foramen vasculare distale shallowly excavated; fossa metatarsi I extends proximad; hypotarsi deflected laterad; on proximal end, crista medialis flexoris digitorum longus present; sulci for tendon of musculus flexor perforatus digiti II and musculus flexor hallucis longus present. Remarks: Milne-Edwards (1874) , when describing Erythromachus , possessed both the original accounts and the first subfossil remains then recently discovered in caves on the Plaine Corail, Rodrigues ( Fig. 4 ). These, along with elements of Rodrigues Night Heron Nycticorax megacephalus ( Milne-Edwards, 1874 ) , Rodrigues Turtle Dove Nesoenas rodericanus ( Milne-Edwards, 1874 ) and Rodrigues Parrot Necropsittacus rodricanus ( Milne-Edwards, 1867a ), were sent to Milne-Edwards in Paris by Edward Newton, brother of Alfred Newton, professor at the UMZC ( Milne-Edwards 1869b ; A. Newton 1875b ; Hume 2007 , 2011a , 2014a , b) (data taken from labels). From these he determined that a flightless rail, related to Aphanapteryx on Mauritius , had once occurred on Rodrigues , and proposed a new genus, Erythromachus . As better material became available it was later referred to Aphanapteryx by Günther & Newton (1879) ; however, Piveteau (1945) noted that distinct differences in the cranium justified the generic separation of Erythromachus , which was an assignation followed by Olson (1977) , Mourer-Chauviré et al. (1999) and others, and applied here. As recently shown in the endemic scops owls of Mauritius and Rodrigues ( Louchart et al . 2018 ), there is precedent for differing evolutionary pathways for the two endemic genera of rails.