Palaeopapia eous, Harrison and Walker (1976)

DYKE, GARETH J., 2001, The Fossil Waterfowl (Aves: Anseriformes) from the Eocene of England, American Museum Novitates 3354, pp. 1-16 : 10

Howardi eous Harrison and Walker ( 1976)

Palaeopapia eous Harrison and Walker ( 1979)

Lydekker (1891: 192) placed the specimen

BMNH PAL 4355 (an incomplete anterior portion of sternum) within his fossil gaviiform (loon) taxon Colymboides anglicus . The genus Colymboides had been created on the basis of a humerus from the Lower Miocene of France by Milne­Edwards ( 1867 – 1871). The sternum (BMNH PAL 4355) specimen was originally cataloged as part of BMNH PAL 30330, along with a partially complete left coracoid, the holotype of Colymboides anglicus Lydekker. The sternum was removed by Harrison and Walker ( 1976), made the holotype of Howardi eous , and placed within the order Anseriformes . Both the specimens BMNH PAL 30330 and 4355 are from the same locality, the Upper Eocene of Hordle (Hordwell), Hampshire, and were purchased from the Hastings Collection in 1885.

When it subsequently proved that the generic name Howardia was preoccupied by a bug ( Hemiptera ), Harrison and Walker (1979b) proposed the replacement name Palaeopapia for this taxon. They later tentatively referred an additional specimen, an incomplete left coracoid (SMC C20949; cast BMNH PAL 4405; fig. 7A ), to the genus (Harrison and Walker, 1979a) collected from the Lower Oligocene Hamstead Beds, Isleof­Wight (date unknown).

TAXONOMIC REMARKS: Harrison and Walk­ er ( 1976) noted that BMNH PAL 4355 ‘‘shows no similarity to gaviid sterna’’ but they did not dicuss this further. When Lydekker ( 1891) named the taxon C. anglicus , he noted (p. 193) that the holotype coracoid (BMNH PAL 30330) fitted perfectly into the preserved sulcus carinae of the incomplete sternum. Since this is the case, I agree with the observations of Lydekker ( 1891) that this specimen must be retained as the single referred specimen of C. anglicus , placed within the Gaviidae until further material pertaining to this taxon becomes available. The incomplete left coracoid tentatively referred to Palaeopapia eous by Harrison and Walker (1979a) is not diagnostic at the ordinal level and is regarded here as Aves incertae sedis. Although this specimen is very similar to the coracoids of the Recent teal (e.g., Anas ), having both a cup like cotyla scapularis and an oblique facies articularis sternalis ( fig. 7A ), neither of these characters has been hypothesised as a synapomorphy of Anseriformes (Livezey, 1997) . Indeed, both have a wider distribution within basal Neornithes (Mayr, 1999).

Figures

Fig. 7. Additional specimens pertaining to named fossil waterfowl taxa from the Eocene of England. A, BMNH PAL 4405 (cast of SMC C20949), left coracoid in dorsal aspect (specimen referred to Palaeopapia eous Harrison and Walker); B, BMNH PAL 4412, proximal right scapula in medial view (holotype of Palaeopapia hamsteadiensis Harrison and Walker); C, BMNH PAL 4407, proximal right coracoid in dorsal view (holotype of Paracygnopterus scotti Harrison and Walker). Scale bar is 10 mm.