Attenborough’s long-beaked echidna still survives in the Cyclops Mountains
We didn’t capture any photographic evidence of Z. attenboroughi during the 2022 survey; from the 2023 survey, we obtained 110 echidna photographs (e.g. Fig. 2c–f) from 26 independent capture events, taken by six different cameras deployed at higher elevations in the Cyclops Mountains. We also captured 15 videos (e.g. Supplementary Movies 1–3). Confirming the identification of the photographed animals requires examining features that distinguish different Zaglossus species. The two principal species to consider are Z. attenboroughi, the only species reported to date from higher elevations in the Cyclops, and Z. bruijnii. Though Z. bruijnii is currently thought restricted to the far west of New Guinea, there are historical records from northern regions17, including a museum specimen registered as coming from Humboldt Bay, next to the Cyclops, in 1911 (mammal collection of Museum Zoologicum Bogoriense, Cibinong, Indonesia, specimen number 404). This makes Z. bruijnii a relevant candidate for an echidna species documented in the Cyclops today.
In contrast, there are no records of the most widespread species of Zaglossus, Z. bartoni, from the Cyclops area, though it does have a broad distribution across most other mountain regions of New Guinea, including other NCR18. Z. bartoni and Z. attenboroughi are similar species distinguished – on the basis of the two museum specimens of the latter thus far available – mainly by the markedly smaller size of Z. attenboroughi7. Though we cannot firmly distinguish between Z. attenboroughi and Z. bartoni based on the camera-trap images, the echidnas in the images appear consistent in overall size, and we conclude only one species is present. Current taxonomic consensus is that Z. bartoni and Z. attenboroughi are closely related allospecies that are distributed vicariantly and do not occur sympatrically7. Of the two species, as Z. attenboroughi is the only one so far recorded in the Cyclops, we conclude the camera-trap images are not of Z. bartoni, and are thus either of Z. attenboroughi or Z. bruijnii. This being said, given the widespread distribution of Z. bartoni, and its variability in body size, pelage colour, and fur thickness7, we believe there is a need for a renewed focus on the taxonomy and geographic variation of all Zaglossus. No integrative review of Zaglossus taxonomy drawing on both morphological features and genetic comparisons has ever been published. Future work is needed to evaluate the taxonomic status of various long-beaked echidna populations, and to confirm whether Z. attenboroughi should be recognised as a distinct species or, for example, as a small-bodied population of Z. bartoni.
More morphologically distinctive is the Western long-beaked echidna, Z. bruijnii, which differs from Z. bartoni and Z. attenboroughi in skull features, usually shorter fur, greater likelihood of spines being present on the underside, and in foot anatomy. A key external feature distinguishing Z. bruijnii from other echidna species is the three, or occasionally four, claws on the forefeet – other echidna species have five7. Our camera-trap footage (e.g. Fig. 2c–f) shows individuals with five claws (Fig. 2d) on the forefeet, consistent with Z. attenboroughi but not with Z. bruijnii. From the photographic evidence, combined with the fact that Z. attenboroughi is the only echidna species known from higher elevations in the Cyclops, we conclude the continuing survival of this ‘lost species’. Furthermore, we captured photographs of multiple individuals, seemingly in courtship (Fig. 2f), suggesting that not only does Z. attenboroughi survive, but its population is also reproducing.
Attenborough’s long-beaked echidna once lived in another North Coastal Range
We also present here, for the first time, subfossil bones of a small Zaglossus consistent with Z. attenboroughi. The material comes from the Lachitu Cave archaeological site (Papua New Guinea National Museum & Art Gallery collections, site code RIQ), found circa 80 km east of the Cyclops in the Oenake Range of Papua New Guinea and excavated in 2004-5 by the Australian National University19 (Fig. 1). We identify these skeletal remains (Supplementary Fig. 1) as Z. attenboroughi on the basis of their small size relative to Z. bartoni and Z. bruijnii, and their morphological consistency with a Z. attenboroughi skeleton in the Australian Museum collections (AM M98529), indicating the species once extended further east into another NCR and into low-lying coastal rainforest. The fossil fragments were found in sedimentary layers, Late Pleistocene to Middle Holocene (c.30,000 to 6,000 years BP) in age according to the site’s marine-shell radiocarbon dating sequence, but is absent from the most recent Late Holocene units (500 years BP to contemporary times). Z. attenboroughi is no longer found outside the Cyclops Mountains; it has not been detected in faunal surveys by Marshall, Menzies, Flannery, Seri, and German, amongst others, in the Oenake, the Bewani, the Torricelli, and the Prince Alexander Ranges of Sandaun and East Sepik Provinces (Papua New Guinea) or their surrounding lowland environments20,21,22. Echidnas of any kind appear to be unfamiliar or unknown to contemporary hunters in these areas (Flannery, pers. comms. 2004), suggesting localised decline or extinction in the Oenake Mountains18 since the Late Pleistocene. However, to our knowledge, no camera-trap studies have been conducted in the Oenake range, and there has been a paucity of surveys of Indigenous and local knowledge; further surveys may, therefore, be merited.
