Chalinolobus orarius, Parnaby & King & Hamilton & Eldridge, 2024

Parnaby, Harry E., King, Andrew G., Hamilton, Steve & Eldridge, Mark D. B., 2024, A new species of lobe-lipped bat (Chalinolobus: Vespertilionidae) from southern Papua New Guinea, Zootaxa 5492 (3), pp. 301-324 : 312-316

Chalinolobus orarius sp. nov.

urn:lsid:zoobank.org:act:59A2AE19-54E5-45CB-A35E-8A7EA8793F77

Figs. 8–10 . Tables 2–4 , 7 .

Holotype. AM M.15114, (field number H13), male, body in alcohol, skull extracted, captured in a mist-net on 7 June 1984 by H. Parnaby and Peter Wilson, Gordon, -9.446°, 147.199° (a suburb of Port Moresby), Central Province, Papua New Guinea. Tissue samples stored in liquid nitrogen taken in the field have the same field number as the body and were lodged in the South Australian Museum.

Paratypes (n = 8). Champion House , Goldie Street, -9.458°, 147.157°, Port Moresby, Papua New Guinea, all adult females collected by Dr James I. Menzies from a roof cavity: M.10385, (UPNG no. 461), male, study skin & extracted skull, collected 3 Nov 1969; M.10386, (UPNG no. 462), female, study skin & extracted skull, collected 4 Nov 1969; M.10387, (UPNG no. 467), female, body in alcohol with skull in situ., collected 3 Nov 1969; M.10388, (UPNG no. 469), female, body in alcohol with skull in situ., collected 3 Nov 1969; M.10389, (UPNG no. 471), female, body in alcohol with skull in situ., collected 3 Nov 1969, M.10390, (UPNG no. 471) female, body in alcohol with skull in situ, humerus extracted, collected 3 Nov, 1969; M.15115, (field number H91), female, body in alcohol with skull in situ., collected 17 June 1984 by H. Parnaby and Peter Wilson from the type locality; M.49709, (field number of body R12245 , PNGM 28231 on long term loan to AM), female, body in alcohol with extracted skull, M.49709.001, frozen tissue, field liver sample number CHNI1 , AM EBU tissue number 99826, collected in a mist-net on 9 Nov 2006 by Steve Hamilton from a survey base camp at -8.236°, 141.808° approx. 4 km E of new Serki village, Western Province, Papua New Guinea .

Measurements of the type series are given in Table 7 .

Diagnosis. Distinguished from all other species of Chalinolobus by the combination of an enlarged ear margin which terminates as a lobe near the angle of the mouth ( Fig. 8 ), and the presence of a secondary cusp on I 1 ( Fig. 9 ). Further differentiated by DNA sequence divergence of at least 6.7% in the mtDNA COI gene from other sampled Chalinolobus species. Distinguished from Australian C. gouldii gouldii , C. gouldii venatoris and Norfolk Island C. cf. gouldii , the only other Chalinolobus in which the enlarged ear terminal lobe is present, by smaller mean body size, e.g. mean FA = 37.24 mm (n = 8 females) vs. northern Australian C. gouldii 40.97 mm (n = 66 females) ( Table 4 ). Northern Australian C. gouldii (north of latitude 20° S) of equivalent forearm length to C. orarius sp. nov. tend to have larger skulls, e.g. CON typically greater than 12.9 mm, C 1 –C 1 usually greater than 4.8 mm and CM 3 greater than 5.0 mm ( Table 3 ).

Distribution. Recorded from Serki, Western Province and Port Moresby, Central Province, Papua New Guinea.

Biology. The limited information about New Guinean Chalinolobus summarised by Bonaccorso (1998) is now in doubt, pending clarification of how many species of the genus occur in PNG. Twins have been recorded from C. orarius sp. nov. at Port Moresby in a maternity colony located in the roof of a building. The species is suspected to roost in tree hollows and is known to roost in buildings. Bonaccorso (1998) states that C. nigrogriseus forage in riparian gallery forest and might not travel far into adjoining forest and woodland but this could have been drawn from Australian studies. If those observations were made in PNG, it raises the possible association of C. orarius sp. nov. with gallery forest in addition to the open habitats discussed below.

Etymology. Derived from the Greek adjective oraria meaning “of the coast”, a reference to the species distribution in the coastal and subcoastal eucalypt savannahs of southern New Guinea.

Common name. Coastal Lobe-lipped Bat is suggested as a vernacular name for this species.

Remarks. Although Australian C. n. nigrogriseus has the closest overall resemblance in external features and general body size to C. orarius sp. nov., it is readily distinguished by the ear margin which terminates in a rudimentary skin lobe near the angle of the mouth and the secondary cusp on I 1 is invariably absent. Smaller individuals of C. gouldii with forearm length less than 40 mm, especially those from far northern NT and north Qld can be separated from C. orarius sp. nov. by the invariant absence of a secondary cusp on I 1 and which have relatively larger skulls. The two-tone dorsal fur colouration, grading from dark shoulders to lighter rump fur typical of northern Australian C. gouldii contrasts with the more uniform dark dorsal fur of C. orarius sp. nov. ( Fig. 10 ). Although dorsal fur colouration is a potentially useful guide in distinguishing C. orarius sp. nov. from northern C. gouldii , individuals of the latter species occasionally have uniform dorsal fur colour. Melanistic individuals aside, the two-tone dorsal fur gradation can also be absent during stages of fur moult.

The conspicuously enlarged terminal ear lobe is present in only three other Chalinolobus taxa: C. gouldii from mainland Australia and Tasmania including the type series of C. gouldii venatoris Thomas, 1908 from Alexandria NT, and the presumably extinct Norfolk Island Chalinolobus sp. , assigned to C. gouldii in the past. The ear lobe of C. dwyeri , though enlarged, does not approach the relative size of C. gouldii .

The dentition of the holotype of C. orarius sp. nov. broadly resembles that of the holotypes of C. n. nigrogriseus and C. gouldii venatoris , based on comparisons with photographs of the upper toothrows of the latter two holotypes. Thus, the first upper premolars are minute, an antero-lingual cusp is present on the second upper premolars and the third molars are unreduced. The pronounced secondary antero-lateral cusp on I 1 is absent in the latter holotypes and is also absent in the holotype of C. nigrogriseus rogersi , which also lacks an antero-lateral cusp on the second upper premolars ( Van Deusen & Koopman 1971). A detailed assessment of the diagnostic value of dental characters is premature and requires a better understanding of infra-specific variation within these taxa.

Distribution and habitat of Chalinolobus in Papua New Guinea

Records attributed to C. nigrogriseus from Papua New Guinea are summarised by Bonaccorso (1998) as having a coastal distribution, postulated to be below 300 m elevation by Ziegler (1982) and Bonaccorso (1998). It remains to be established what proportion represent C. orarius sp. nov. but a review of all Chalinolobus locality records is potentially informative.

A summary of locality data for PNG Chalinolobus ( Table 8 ) indicates that the likely elevation for most is below 100 m , and most of these are probably below 50 m. The precise location is not available for some records but the lowland context within an arbitrarily selected, 5 km radius of the general locality places an upper elevational limit. For example, the record from “ Six Mile Saraga ” is in a suburb of Port Moresby in which most land is below 100 m , with limited hills and ridges to c. 150 m.

Locality records were examined in relation to the broad vegetation classes mapped by Paijmans (1975) using the vegetation shape files of the analysis of Joseph et al. (2019). All localities were dominated by open vegetation classes within 5 km radius of the estimated site, mainly savannah, woodland, swamp vegetation, grassland or mosaics of these classes ( Fig. 11 , Table 8 ). Kupiano was the only site where extensive mangroves were mapped within 5 kms. This indicates that, in the context of the relatively coarse scale of vegetation mapping, the distribution of Chalinolobus in PNG is associated with open habitats. The influence of gallery forest needs to be examined but was not mapped by Paijmans (1975).

The broad distribution of potentially suitable habitat was examined by amalgamating the dominant vegetation classes surrounding locality records into two categories: savannah and savannah mosaics, and woodland and woodland mosaics. An overlay of these categories with elevation below 150 m reveals a limited and disjunct distribution of these vegetation categories through the lowlands of southern PNG ( Fig. 12 ), as demonstrated by Joseph et al. (2019).

Figures

FIGURE 8. Similarity of the enlarged lobe (white arrow) formed by the downwardly directed, lower ear margin near the angle of the mouth of a) and b), AM M.49709 (PNGM 28231), adult female from Serki, Western Province PNG, paratype of C. orarius sp. nov.; and c), southern Australian C. gouldii, AM M.16073, adult male, Barakula State Forest, NW of Chincilla, Qld. Not to scale. (Photos: a and b, Steve Hamilton; c, Ron Lovatt, AM Digivols).

FIGURE 9. Holotype of C. orarius sp. nov., AM M.15114 adult male from Port Moresby, PNG. (Photo: Ron Lovatt, AM Digivols).

FIGURE 10. Pelage colour of a), dorsal, and b), ventral surface of paratype of C. orarius sp. nov., AM M.10385 adult female study skin from Port Moresby, PNG, compared to variation in northern C. gouldii from the Gulf of Carpentaria, Qld: c), AM M.8515 adult female, and d), AM M.8516 adult male. (Photos: Harry Leung, AM).

FIGURE 11. Localities of PNG Chalinolobus with vegetation categories of Paijmans (1975), showing 5 km radius circle around locations. a), Bandaber, b), Serki, c), Port Moresby and d), Kupiano. Based on vegetation shape file of Joseph et al. (2019). Abbreviations for vegetation classes are: Sa, savannah; W, woodland, Wsm, swamp woodland; G, grassland, Ga, current and abandoned gardens and plantations, Gsw, swamp grassland; Hsw, herbaceous swamp vegetation; Ma, mangrove; Sc, scrub; FB, littoral forest; Fd, dry evergreen forest; Fsw, swamp forest; FHs, small-crowned lowland hill forest; FHm, medium-crowned lowland hill forest; FPo, open forest on plains; FPs, small crowned forest on plains; FPI, large to medium-crowned forest on plains.

FIGURE 12. Locality records of Chalinolobus from the island of New Guinea showing amalgamations of Paijmans vegetation categories: savannah (yellow); mosaics with savannah (orange); woodland (pale green) and mosaics containing woodland (dark green). Elevations above 150 m are in dark red. Six localities from Port Moresby environs (map inset) are: 1, Waigani Sewerage works, 2, PNG Museum & Art Gallery roof, 3, Gordon, 4, Saraga, 5, Champion House and 6, Paga Hill. Second inset shows environs of Kupiano. Vegetation map modified from figure 1 of Joseph et al. (2019) using a vegetation shape file kindly provided by Christopher Wilson, CSIRO Canberra.