Mus, Linnaeus, 1758

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 : 364

Mus (?) echimyoides Ramsay, 1877g

Proc. Linn. Soc. N.S.W. (ser. 1) 2(1): 15. (July 1877).

Common name. Pacific Rat.

Current name. Rattus exulans browni ( Alston, 1877) , following Taylor et al. (1982).

Syntypes. (2). M.2364 , (skin tag 48), male, skull, study skin. An early tag attached to the skin was most likely written by Ramsay and has inscribed: “No. 48 Type of the species Mus echymoides [sic]. Duke of York Islands (G.B.) [= George Brown] Bought of Cockerell E-- [indecipherable initials, apparently E.P.R.]”; M.2365 , (skin tag 52), male, skull, study skin, tag in Ramsay’s hand states: “Type of the species ♂ Mus echymoides . Duke of York Is, George Brown”. Both specimens were registered on 16 December 1913 and entered with identical data: “ Mus echymoides [sic] male TYPE, Duke of York Island , Purch. from Cockerell. Rev. George Brown.” There is no indication in the M Register entries of any previous Palmer Register number .

Condition. M.2364: incomplete cranium, missing both zygomatic arches, occipital area and both auditory capsules; holes in left and right frontals; left dentary missing coronoid process, right dentary with fracture in condylar process, left mandibular incisor is shorter. Study skin: bald patch on the dorsal surface, fracture in the proximal end of the tail and missing tail tip. M.2365: incomplete and damaged cranium, missing right zygomatic arch, posterior braincase wall, left zygomatic arch broken. Study skin has a dorsal bald patch on the left shoulder and a dorsal hole on the right shoulder, right ear damaged, tail missing parts of skin in two sections, and tail detached but tied to the dorsal surface of the body.

Cranial measurements (mm). M.2364: GL, —; NasL, 11.74; NasB, 3.55; DIL, 8.73; APV, 5.75; PAL, 16.69; UMR (alv.), 5.08; ZB, —; POC, 5.00; BUL, —; MB, —; DL (condyl.), 16.74; LMR (alv.), 4.99. M.2365: GL, —; NasL, 10.76; NasB, 3.22; DIL, 7.54; UMR (alv.), 5.14; ZB, —; POC, 4.92; BUL, —; MB, —; DL (condyl.), 15.38; LMR (alv.), 4.63.

Type locality. “Duke of York Island” (Ramsay), East New Britain Province, Papua New Guinea.

Comments. Ramsay indicated that he examined sub-adults and adults of each sex, but failed to indicate the number of specimens in the type series, or cite field numbers or registration numbers (the new A Register numbering had not yet commenced). He stated that no skulls were available and that his description was based on external criteria.

Syntype skin M.2364 has what is most likely Ramsay’s original tags, written in his hand. Both syntype skins have printed paper tags attached with the only information being the numbers 48 and 52, respectively. We suspect that the numbers refer to Palmer Register numbers, and if so, are inconsistent with original data entered by Palmer in the Register and with amendments made when M numbers were assigned in 1913. Both syntypes are likely to have been re-registered from a series of specimens PA.48 to PA.54 originally in alcohol, that also include likely syntypes of Mus musavora Ramsay. It seems certain that confusion existed in assigning numbers to specimens when registered by Palmer. An annotation in Troughton’s hand to the old specimen index card for PA.50–51 (marked Mus echmyoides [sic], mounted group of two) notes “Registration numbers doubtful according to Palmers entry, see specimens registered as M.2364–65 which are definitely labelled “types”“.