Chaetocercus cristicauda Krefft, 1867a

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 : 305-306

Chaetocercus cristicauda Krefft, 1867a

Proc. Zool. Soc. Lond. 1866: 435, plate xxxvi. (25 April 1867).

Common name. Crest-tailed Mulgara.

Current name. Dasycercus cristicauda ( Krefft, 1867a) , following Jackson & Groves (2015).

Holotype. M.11342 (= PA.669½) by subsequent determination. Sex not determined, skull, skin mount ( Figs 7–8 ). Original entry in Palmer’s hand for PA.6691/2 states only “ Chaetocercus cristicaudatus [sic] S. Australia Mounted greatly mutilated”. Skin mount and skull re-registered as M. 11342 in July, 1980.

Condition. Cranium: both left canines are loose, missing upper left 1st and 2nd incisors, all lower incisors are lost, right dentary is broken in two. The skull is not numbered. Incomplete and damaged skin mount on a base, both ears are torn, snout is almost detached, left front limb is almost detached, fur is patchy, very poor condition. Woolley (2005b) notes that the mount is a composite, having been repaired using fur and perhaps a foot, from other specimens, not necessarily of this species.

Cranial measurements (mm). M.11342: GL, 33.99; ConL, 33.99; BasL, 31.49; NasL, 10.94; NasB, 4.96; UC1–C1 (alv.), 6.09; APV, 2.85; PPV, 4.83; PAL, 17.76; UPM (alv.), 1.46; UMR (alv.), 8.81; ZB, 21.66; POC, 7.57; BUL, 7.24; MB, 18.91; DL (condyl.), 25.4 (left dentary); LPM (alv.), 1.35; LMR (alv.), 9.96.

Type locality. South Australia. Krefft states that the type locality was “probably Lake Alexandrina” but this is considered unlikely, and the specimen could have been collected by Waterhouse during a trip from Port Augusta to Coffin Springs (see Woolley, 2005b) .

Comments. Krefft established Chaetocercus for his new species and the cranial and dental criteria used in his generic diagnosis imply that he examined a reasonably intact skull. In his original account, Krefft does not indicate the number of specimens examined, but he later categorically states that it was one specimen ( Krefft, 1876). PA.669½ was registered in the Palmer Register in c. 1878, with the comment that the mounted specimen is “greatly mutilated” but there is no mention of a skull. Krefft’s original skull was clearly not available to Spencer (1896b), who borrowed the holotype skin mount and had to draw on Krefft’s statements for information on dental structure. Spencer expressed great difficulty deciding if his material was the same species named by Krefft, no doubt due both to the poor condition of the skin mount, and the fact that his material also included examples of D. blythi ( Waite, 1904) , see Woolley, 2005b.

Mahoney & Ride (1988b) cite M.11342 skin mount as the holotype but do not mention a skull. We are unable to either validate, or refute the association of the skull with the holotype skin. Although Krefft provided descriptions of the skull and dentition in his original and subsequent accounts, he did not publish illustrations or cranial and dental measurements. It seems likely that the putative type skull was located during collection inventories undertaken by Troughton, probably sometime after 1937, the year Tate visited the AM ( Troughton, 1937a: 125), but we have not yet found any documentation on this issue. The specimen index card for PA.669½ (written after c. 1900), written in handwriting that seems to predate Troughton, indicates a skin mount but lists “Skull:?”, indicating that the skull had not been located. This is reflected by Tate (1940), who lists a skin and “Skull?” and does not provide further information on the holotype skull ( Tate, 1947).

Woolley (2005b) concluded that she had no reason to doubt the authenticity of the holotype skull, which she considered to be a good match against Krefft’s description. Dr Pat Woolley has drawn our attention to three letters on the dorsal surface of the holotype skull, written in old ink, that she interprets as “ch c.”—perhaps an abbreviation for Chaetocercus cristicauda , which is written on an old label in the skull box. Another interpretation is that the letters are “ch ae.” and we also note that there is another symbol, possibly “P” (see Fig. 8 ). Krefft erected Chaetocercus in 1867, but Peters (1875) proposed the replacement name Dasycercus (see Jackson & Groves 2015: 51). Initially this was not adopted by Australian zoologists (including Spencer) who applied Phascogale to this species for several decades following the arrangement of Thomas (1888a). Attempts to extract DNA from the holotype skin have not been successful to date.

Figures

Figure 7. AM M.11342 (= PA.669½), holotype skin mount of Chaetocercus cristicauda Krefft, 1867a. (Photography by Sally Cowan).

Figure 8. AM M.11342 (= PA.669½), holotype skull of Chaetocercus cristicauda Krefft, 1867a. (Photography by Sally Cowan).