G.J. DYKE 



Fig. 1 Pseudastur macrocephalus holotype specimen (WDC-C-MG-94), 

 covered with ammonium chloride to enhance contrast. Scale bar = 

 10mm. This figure reproduced from Mayr (1998) with permission, 

 Forschunsinstitut Senckenberg. 



medialis is pointed. The sternal facet is shallow, rectangular and 

 located on the plane of the coracoid surface (not obliquely under the 

 proximal end). 



Humerus (Fig. 2D). In caudal view, the tuberculum dorsale (al- 

 though broken distally ) appears to point distally. The incisura capitis 

 and tuberculum ventrale are obscured by sediment, although the 

 latter appears to have been well developed. The fossa 

 pneumotricipitalis is shallow, shelf-like and bordered laterally by a 

 pronounced attachment for the musculus infraspinatus that is well 

 developed and square-shaped. The lateral margin of the crista 

 deltopectoralis is extremely curved (almost semi-circular) in outline, 

 the crista bicipitalis meets the shaft at about 70 degrees; the crus 

 dorsale fossae is obscured. 



Femur (Fig. 2C). This is a very short and stocky element (relative 

 to the preserved humeral length; see measurements). The fossa 

 trochanteris is shallow and obsolete; the trochanter is not well 

 developed and is rounded and blunt. The iliac facet is flat and in line 

 with the head of the femur. The femoral head is turned distally and 

 overhangs the shaft somewhat; the angle between the head and the 

 shaft is about 90 degrees. The shaft is stocky and straight with little 

 lateral curvature, there is no offset between the proximal and distal 

 ends. 



BMNHA6184 



Tarsometatarsus (Fig. 2F). A large foramen vasuculare distale 



Fig. 2 Pseudasturid specimens from the London Clay Formation. A-E. 

 BMNH A 62 1 8; A, portion of left coracoid; B, left scapula; C, left 

 femur; D, portion of right humerus; E, right coracoid. F, BMNH A 6184, 

 distal end of a left tarsometatarsus. G, BMNH A 6224. proximal right 

 tarsometatarsus. All figures are x 2. 



is present that is ovate in outline. In plantar view, the surface of the 

 tarsometatarsus is smoothly excavated distally. The trochlea meta- 

 tarsi IV is broad anteriorly and bears a sehnenhalter (Steinbacher, 

 1935) that is not separated from the remainder of the trochlea by a 

 groove (contrary to all known psittaciforms; Mayr & Daniels. 1998). 

 On the lateral surface of the retroverted portion of trochlea metatarsi 

 IV there is a marked and rounded prominence. The trochlea meta- 

 tarsi III is broad and has a marked medial furrow that is bordered by 

 two very prominent lateral ridges. This trochlea is separated from 

 trochlea metatarsi 11 by a U-shaped depression. Trochlea metatarsi II 

 is square is shape and very flat across the surface of the distal end (i.e. 

 knuckle-view). 



Measurements 



Bmnh a 62 1 8 : humerus, total preserved length - 1 5mm, width of 

 caput humeri - 2mm (insicura capitis infilled with sediment); right 

 coracoid, total length - 14mm; length acrocoracoid to procoracoid- 

 1.2mm; proximal portion left coracoid, total preserved length - 

 8mm; length acrocoracoid to procoracoid - 1 .3mm; left femur, total 

 length - 16mm; right scapula, total length - 15mm. 



Bmnh A 61 84: tarsometatarsus, total preserved length - 5.2mm 



