Paragallinula, Sangster, Garcia-R & Trewick, 2015

Sangster, George, García-R, Juan Carlos & Trewick, Steve A., 2015, A new genus for the Lesser Moorhen Gallinula angulata Sundevall, 1850 (Aves, Rallidae), European Journal of Taxonomy 153, pp. 1-8 : 4-6

Paragallinula gen. nov.

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Type species

Gallinula angulata Sundevall, 1850 . Monotypic.

Differential diagnosis

Paragallinula gen. nov. differs from Gallinula , Pareudiastes , Tribonyx and Porphyriops in that (i) the orange suffusion on the frontal shield does not encompass the entire shield (in Gallinula encompassing entire frontal shield ( Fig. 2 ); in Pareudiastes , Tribonyx and Porphyriops no suffusion of orange). In addition, Paragallinula gen. nov. differs from most species in the Fulica -clade (except T. ventralis ) in (ii) showing marked sexual plumage dimorphism ( Taylor 1996; Taylor & van Perlo 1998). Paragallinula gen. nov. further differs from Gallinula in (iii) the lack of a contrasting reddish band (“garter”) on the legs immediately proximal to the ankle joint (present in Gallinula ) ( Fig. 2 ).

Paragallinula gen. nov. differs from Fulica in (ii) gradual change in colouration on hindneck from dark grey head to paler lower neck and back (abrupt change in Fulica ); (iii) absence of broad cutaneous lobes on digits II–IV of feet (present in Fulica ); and (iv) presence of narrow cutaneous folds on lateral and medial sides of digits I–IV of feet (absent in Fulica ). Paragallinula also differs from Fulica in at least 12 diagnostic osteological characters (characters 120, 124, 125, 127, 139, 216, 274, 298, 311, 312, 316, 343 in Livezey 1998, to which is referred for descriptions of characters and their states).

Paragallinula gen. nov. further differs from the two species of Pareudiastes in (iii) frontal shield with acuminate posterior margin (squared margin in Pareudiastes ); (iv) ventroanterior position of nasal depression (ventromedial in Pareudiastes ); (v) fully feathered lores (in Pareudiastes , lores with sparsely feathered, yellow-orange area from base of maxilla to orbit); (vi) gradual change in colouration on hindneck from dark grey head to paler lower neck and back (very dark without noticeable change in colour from head to back in Pareudiastes ); (vii) flank feathers with large white streaks (no streaks in Pareudiastes ); (viii) undertail-coverts white dorsolaterally, black ventromedially (entirely black or brownish-black in Pareudiastes ); (ix) six pairs of rectrices (four in Pareudiastes ); (x) rectrices forming normally-shaped tail (in Pareudiastes , rectrices very short barely protruding beyond uppertail- and undertail-coverts); (xi) leading edge of distalmost primary with narrow white margin (absent in Pareudiastes ); (xii) underwing-coverts with white bars (not barred in Pareudiastes ); (xiii) bend of wing whitish (no white colouration in Pareudiastes ); and (xiv) presence of narrow cutaneous folds on lateral and medial sides of digits I–IV of feet (absent in Pareudiastes ).

Paragallinula gen. nov. further differs from Tribonyx in (ii) broad naked area on crown in downy plumage (absent in Tribonyx ); (iii) long, filamentous white filoplumes in downy plumage (absent in Tribonyx ); (iv) frontal shield with acuminate posterior margin (rounded in Tribonyx ); (v) undertail-coverts white dorsolaterally, black ventromedially (entirely blackish in Tribonyx ); (vi) six pairs of rectrices (eight in Tribonyx ); (vii) underwing-coverts dark grey, blackish or black (medium brown in Tribonyx ); and (viii)

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bend of wing whitish (no white colouration in Tribonyx ). Paragallinula also differs from Tribonyx in a single osteological character: (ix) ossa digitorum pedis, digiti tertius, phalanx intermedialis (secundi) is equal to or longer than phalanx quartus (in Tribonyx modally shorter than phalanx distalis (tertius).

Paragallinula gen. nov. further differs from Porphyriops ( P. melanops ) in (iii) broad naked area on crown in downy plumage (absent in Porphyriops ); (iv) long, filamentous white filoplumes in downy plumage (absent in Porphyriops ); (v) ventroanterior position of nasal depression (ventromedial in Porphyriops ); (vi) feathers at base of bill, lores and crown not contrasting with rest of head (in Porphyriops contrastingly black); (vii) flank feathers mostly plain but with large white streaks at tips (flank feathers brown-grey, spotted white in Porphyriops ); (viii) central belly dark slate-grey (whitish in Porphyriops ); (xi) undertailcoverts white dorsolaterally, black ventromedially (white in Porphyriops ); and (x) rectrices dark grey or black (brown in Porphyriops ). In addition, there are two diagnostic osteological differences between Paragallinula and Porphyriops : (xi) os frontale, facies dorsalis moderately convex (flat or slightly concave in Porphyriops ), and (xii) os squamosum, fossa temporalis distinct, separated medially from each other by significantly broad, elevated expanse of os frontale (in Porphyriops , indistinct, shallow, limited to region immediately ventral to processus postorbitalis).

Etymology

The generic name is derived from the Greek para (beside) and the Latin gallinula (a little hen or chicken). It denotes the resemblance of P. angulata to species of Gallinula but highlights that they are independent evolutionary lineages. The gender of the name is feminine.

Distribution

Paragallinula angulata is found in most of the African continent from Senegal and Gambia to Ethiopia, Namibia, Botswana and South Africa.

Figures

Fig. 2. Lesser Moorhen Paragallinula angulata Sundevall, 1850, Kgomo Kgomo, South Africa, Feb. 2011 (photo by Mark Tittley). This photograph illustrates two diagnostic character states differentiating Paragallinula from the genus Gallinula: the orange colouration on the frontal shield does not cover the entire shield, and the lack of a contrasting reddish band on the legs proximal to the ankle joint