Porzana ralphorutn, new species
(Fig. 17B, D, F, M)
"medium-large Oahu rail" Olson and James, 1982b:36, 44; 1984:771; James, 1987.
"Porzana" sp., medium flightless rail" James, 1987: 227.
Holotype: Right tarsometatarsus, USNM 426114 (Fig. 17M). Collected 10 July
1981 by Storrs L. Olson, Helen F. James, James and Emilee Mead, Patrick McCoy,
and Virgil Meeker.
Type locality: Site 50-Oa-B6-22, Barbers Point, Oahu, Hawaiian Islands.
Distribution: Oahu: Barbers Point, Kuliouou shelter, and Ulupau Head.
Etymology: To our friends C. J. Ralph and Carol Pearson Ralph, who assisted
our research in the islands in many ways and whose hospitality is deeply appreciated.
Measurements (ram) ofholotype: Length, 35.7; proximal width, 5.0; shaft width
at midpoint, 2.2; distal width, 4.9.
Paratypes: Premaxillary symphyses, USNM 426116 (Fig. 17B), 426117-426119;
mandibular symphysis, USNM 426120 (Fig. 17D); right humerus, USNM 426121
(Fig. 17F); proximal end of left femur, USNM 426122; right tibiotarsus lacking
proximal end, BBM-X 153139; distal end of right tibiotarsus, USNM 426123;
distal end of left tibiotarsus, USNM 385876.
Measurements (ram) ofparatypes: (These are in the same sequence as the preceding.)--
Premaxillary symphysis: length from anterior margin of nostril, 7.3,
5.5, 5.5, 6.7. Mandibular symphysis: length, 2.5. Humerus: length, 26.7; proximal
width, 4.9; shaft width at midpoint, 1.3; distal width, 3.9. Femur: proximal width,
6.8. Tibiotarsus: length from distal end of fibular crest, 40.9; shaft width at midpoint,
2.2; distal width, 4.9, 4.9, 4.8.
Diagnosis: Larger than any of the flightless Rallidae known so far from the
Hawaiian Islands except Porzana severnsi. Differs from P. severnsi as follows:
premaxillary and mandibular symphyseshorter and wider; humerus larger and
more robust, especially the shaft, and bicipital crest more rounded, not as angular;
distal tendinal opening of tibiotarsus smaller and more rounded, not longer in its
transverse diameter; tarsometatarsus with distal foramen situated farther distally.
Remarks: This species is much scarcer as a fossil than the tiny species P. ziegleri,
with which it was sympatric. The premaxillary symphysis is even shorter than in
P. severnsi, in which the symphysis is shorter than in most species of Porzana.
The paratypica ! mandibular symphysis, if correctly assigned, is extremely short,
unlike the rather lengthened, troughlike symphysis ofP. severnsi. It is curious that
the two species of Porzana from Oahu each differ from their relative on Maui in
having the wing elements less reduced.
elibrary.unm.edu/sora/om/om045.pdf
