Macropus tibol Miklouho-Maclay, 1885b

Parnaby, Harry E., Ingleby, Sandy & Divljan, Anja, 2017, Type Specimens of Non-fossil Mammals in the Australian Museum, Sydney, Records of the Australian Museum 69 (5), pp. 277-420 : 337-338

Macropus tibol Miklouho-Maclay, 1885b

Proc. Linn. Soc. N.S.W. (ser. 1) 10(2): 141, pl. 19, figs 1–11. (31 July 1885).

Common name. New Guinea Pademelon.

Current name. Thylogale browni (Ramsay, 1877e) , following Flannery (1992).

? Syntype. M.2031, unsexed study skin with extracted skull, entered in the M Register as “? New Guinea ”, received from Macleay Museum Committee in 1907 and registered 4 February 1909 .

Condition. Cranium and dentaries largely intact but bone porous and crumbling; both dentaries fused to cranium. Cranium: most incisors have disintegrated and are lost; soft palate adhered to palate; hole in anterior of braincase roof and much of roof has been crushed inward. Study skin intact and in reasonable condition; claws of both manus corroded by salt; claw sheaths missing from left pes digits 4 and 6.

Type locality. “ Macleay coast” = north of Finisterre Range and east of Madang, Madang Province, Papua New Guinea .

Comments. We cannot exclude the possibly that M.2031 is a syntype but on balance it possibly is not. Although the dimensions of the skin and skull match those provided for one specimen in Miklouho-Maclay’s description (see below), the condition of the skull is inconsistent with the skull figured in the original description. The skull is badly corroded, encrusted with deposits and partly cleaned, in contrast to the cleaned skull illustrated by Miklouho-Maclay. The corroded skull is typical of specimens obtained from Andrew Goldie , who as far as we are aware, is the only collector of that period to store New Guinea material in “brine” rather than alcohol. One possibility is that the syntype skins were initially stored in alcohol by Miklouho-Maclay and later transferred to brine barrels with Goldie material at the Macleay Museum , although this seems unlikely to us. Further , it seems unlikely that having extracted the brine corroded skull, Miklouho-Maclay would have subsequently returned it to the preserving solution. The documentation associated with the transfer of these specimens from the Macleay Museum in 1907 makes no mention of skulls, but this might have been an oversight.

In his original account Miklouho-Maclay stated that he obtained two specimens only, both males of similar body size. Evidently he provided illustrations of both syntype skulls as revealed by his fig. 6 illustration of palatal ridges showing fully erupted rear molars, compared to incompletely erupted molars of the cleaned skull in his fig. 9. MiklouhoMaclay indicates that he shot the first specimen in 1871 and that his published illustrations and body measurements were taken of the second specimen the same day that it was killed by dogs in 1876. He states that both specimens are adult, but Thomas (1888a) regarded them as juvenile.

The two syntypes, which are not listed by Stanbury (1969) as being in the Macleay Museum , do not appear to have been reported since the original description.A search of the MMUS collection by HEP and MMUS staff in 2016 failed to locate candidate specimens. Miklouho-Maclay does not reveal whether either specimen reached Sydney after his field work in Papua New Guinea but if so, it would likely have been held in his private collection given his habit of acknowledging specimens in Macleay’s private collection in his published works of other proposed mammal taxa. The caption to his fig. 1 of the whole animal states that it was based on a sketch from life and a photograph of a stuffed specimen, implying that he did not necessarily have access to a study skin while preparing the description.

Although it is not known whether Miklouho-Maclay’s original specimens have survived and whether they left Australia with him on returned to Russia in 1886 ( Maclay, 1974), it is possible that the AM material contains one of his syntypes of Macropus tibol . The MMUS sent a number of containers of specimens in alcohol to the AM, which were registered on 4 Feb 1909. Included were ten specimens of wallabies: M.2031, Macropus browni ; M.2032–33, Thylogale brunii originally entered in the register as? Macropus browni , and M.2034–40, seven specimens originally entered as Dorcopsis macleayi (now Dorcopsulus macleayi ). The original M Register entry states “possibly co-types” and “?New Guinea ”, meaning that cotypes are possibly included amongst the ten specimens. Given that Dorcopsulus macleayi appears to have been described from a single specimen now in the MMUS (MMUS M381, see Stanbury, 1969), any “co-types” are more likely to be amongst the specimens of Thylogale : M.2031–33. The skulls in this series are badly decalcified by storage in brine rather than alcohol, as described by Miklouho-Maclay for material sent from Goldie in Macleay’s private collection.

The skull of M.2031 is decalcified but it closely resembles one of the skulls illustrated in the original description, being a young animal at the same stage of molar eruption. Further, M.2031 closely approximates the size of the skull illustrated by Miklouho-Maclay at nature size, taking into account likely distortion from the camera lucida drawing by MiklouhoMaclay, and likely shrinkage of the salt affected skull. Cranial measurements are not given in the original account but greatest skull length and zygomatic breadth, measured from the published hardcopy plate, are greater than M.2031: greatest skull length 80.3 mm vs 72.8; zygomatic breadth 44.6 vs 40.4 mm. However, unlike the skull illustrated in the original account to which M.2031 closely resembles, M.2031 retains the skin on the palate. Further, the mandible is now fused with the cranium.While this might suggest that M.2031 is not a syntype, it is possible that the skin of the palate was loosened for the illustration, and that both the palate tissue and mandible have subsequently adhered to the salt affected skull. The study skin M.2301 is a close match with the dimensions given for one syntype in the original description considering the imprecise demarcation of the tail base in the study skin: nose tip to base of tail c. 13.5 inches vs. 13 inches for the syntype; tail length 9.5–10 inches vs. 9.3 inches and ear length c. 35 mm vs. 34 mm.

Of the two Thylogale specimens with associated skulls sent from MMUS, M.2031 is the only candidate syntype of Macropus tibol , if Miklouho-Maclay’s statement that both syntypes are of similar size is correct. The other specimen, M.2032 (not listed by Flannery (1992)) is a male study skin with a very badly decalcified and distorted skull that far exceeds the dimensions given by Miklouho-Maclay (nose tip to tail base = 20–21 inches vs 13 inches, tail length c. 13.5 inches vs 9.3 inches). However, the stage of molar eruption and the presence of palatal skin ridges, which are firmly adhered to the skull unlike M.2031, are consistent with the illustration of one of the skulls in Miklouho-Maclay’s account but there is no strikingly individual feature such as damage that would secure the association.

The type series of the two other thylogales described by Miklouho-Maclay, both from New Guinea, are accounted for: Macropus gracilis Miklouho-Maclay, 1885a (= Thylogale brunii ) based on the holotype skin and skull in the MMUS ( Stanbury, 1969) and Macropus jukesii Miklouho-Maclay, 1885a (= Thylogale brunii ), see above account.