PROBABLE VALIDITY OF Rallus nigra Miller,
AN EXTINCT SPECIES FROM TAHITI
By MICHAEL WALTERS
The name Rallus nigra is known only from a plate by J. F. Miller, first
published in his Icon. Animalium of 1784, which Lysaght (1956) believed
depicted the rail currently known as Porzana tabuensis (Gmelin), the Spotless
Crake or Sooty Rail, a widespread species occurring from Australia and New
Guinea across the southern Pacific Ocean to the Marquesas Islands and south
to New Zealand. She proposed to substitute Miller's name for Gmelin's on
the grounds of priority, an action which seems unwise as circumstantial
evidence suggests that Rallus nigra represents another, almost certainly
extinct, species.
The plates of Miller and Forster
According to Lysaght's account, the Spotless Crake (Porzana tabuensis) was
discovered at Tahiti and painted by Georg Forster on Cook's second voyage,
and this plate was then copied by Miller. Lysaght continued:
The interleaved text gave no particulars except for the name of the bird,
Rallus nigra, and the locality, Otaheite [i.e. Tahiti]. Miller's plate is very
close to Forster's save that the bird is depicted standing instead of crouching,
that it is almost uniformly black and only slightly paler below, instead of
having a grey head and undersurface contrasting with the back and wings,
and that the iris and legs are bright chestnut brown instead of red.
Lysaght's account actually leans very heavily on the earlier note of Sherborn
& Iredale (1921) who, in discussing Miller's Icon. Animalium (a very rare
book, a copy of which had just come to light) said:
Rallus nigra Miller is the bird long known as Porzana tabuensis (Gmelin),
but the correct application of the latter name is not definitely ascertained.
Thus J. R. Forster described a black bird, but noted that there was a brown
variant. His son painted the Black Rail from "Taheitee" and this painting
is preserved in the British Museum (Natural History), no. 130, with the
native name "Maho" pencilled on it. The drawing was copied and published
with little alteration by Miller under the name Rallus nigra. Forster's MS
name was Rallus minutus, and his localities were "Otaheite et in Tonga-Tabu".
It is, however, quite clear that neither of these plates represents Porzana
tabuensis as Lysaght claims. P. tabuensis has a very conspicuous brown mantle
which is present on neither Forster's nor Miller's plates.
Forster's unpublished plate depicts a squatting rail, charcoal grey on
the head and underparts, black on the back, wings and tail. The legs are
red, the claws greyish. The face is longish and the bill thick and black. The
eye is red with a dark pupil, surrounded by an area of black skin outlined
in orange. It is a very carefully executed painting. In the bottom left-hand
corner, "Taheitee" has been written in pencil, and "Ge. Forster" in ink. In
the bottom right-hand corner is written "Maho".
Miller's plate in the Icon. Animalium is a hand-coloured engraving
depicting a standing rail, charcoal black all over, with suggestions of darker
and less dark areas; but this impression may be due to lines on the original
print. The bill is black but appears thinner than on Forster's plate, the head
is rounder, and a pale yellowish-green line separates the mandibles. The
eye and legs are duller, browner red than in Forster, and the claws are grey,
outlined with thick black lines. There is no suggestion of any bare skin round
the eye.
Miller died in 1796, in the same year that a revised edition of his work
was published. This book, the Cimelia Physica, of which more copies survive
than of the original edition, reproduced the original plates (hand coloured
from the same engravings but executed with rather less care) and added an
interleaved text by George Shaw, of which the paragraph relating to Miller's
Rail runs:
This bird, which the plate represents in its natural size, is a native of Otaheite
and several other islands in the Pacific Ocean. The irides are red. It is a
species which was first discovered during Sir Joseph Banks' voyage to the
Southern Hemisphere. It is said to be subject to some variety in point of
colour, being sometimes much browner than here expressed, with the vent
barred with streaks of black.
Lysaght dismissed Shaw's statement that the rail was discovered on Banks'
voyage as of "doubtful validity", but she seems to have overlooked the fact
that Shaw's account is clearly taken from that of Latham (discussed later).
Shaw was known to be flamboyant and careless, and in this instance he seems
to have misinterpreted Latham's simple ascription of the species to Banks
as meaning Banks had collected a specimen, when Latham probably meant
no more than that the specimen or painting on which he based his description
was in Banks' collection.
The most convincing note on Miller's Rail was that given by J. L. Peters
(1934), who placed Miller's name with a query in the synonymy of the rail
Nesophylax ater (North) from Henderson Island, and added in a footnote:
Miller's plate represents a wholly black rail somewhat larger than tabuensis;
it cannot be identified with any of the known forms of tabuensis and possibly
represents the bird later named Porzana atra or at least a bird closely allied
to It.
As Henderson Island was not discovered until long after Cook's voyages,
Miller's Rail is not likely to have referred to the rail population from that
island, but it may have been an allied form. Lysaght correctly pointed out
that the question of size is irrelevant because the measurements of the rail
on .!iller7s plate do not exceed those of some specimens of Porzana tabuensis.
However, the incompatibility of colouring is an important one, and one which
seems to have been overlooked by all previous writers except Peters.
also known as Nesophylax niger
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