Macronycteris Gray, 1866
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publication ID |
https://doi.org/ 10.3161/15081109acc2017.19.1.001 |
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DOI |
https://doi.org/10.5281/zenodo.6821989 |
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persistent identifier |
https://treatment.plazi.org/id/2B0387CF-FFD6-2E3A-FCC8-F8FBFB218385 |
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treatment provided by |
Diego |
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scientific name |
Macronycteris Gray, 1866 |
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Genus Macronycteris Gray, 1866 View in CoL (p. 82)
New combination — Macronycteris gigas (Wagner, 1845) .
Also including the following species M. commersonii (E. Geoffroy, 1813) , M. cryptovalorona ( Goodman, Schoeman, Rakotoarivelo & Willows-Munro, 2016), M. gigas , M. thomensis (Bocage, 1891) and M. vittatus (Peters, 1852)
Synonyms
Rhinolophus Commersonii E. Geoffroy Saint-Hilaire, 1813 .
Rhinolophus gigas Wagner, 1845 .
Phyllorhina vittata Peters, 1852 .
Phyllorhina Commersoni Peters, 1871 .
Phyllorhina commersonii Dobson, 1878 .
Phyllorhina commersoni var. thomensis Bocage, 1891 .
Hipposideros commersoni Andersen, 1906 .
Hipposideros gigas Wagner, 1845 .
Hipposideros thomensis Bocage, 1891 .
Hipposideros Commersoni Dorst, 1948 .
Hipposideros vittatus Monadjem et al., 2010 .
Hipposideros cryptovalorona Goodman et al., 2016 .
Description of the Genus Macronycteris
Morphological characters
Gray (1866) in his description of Macronycteris , focused exclusively on the forehead and noseleaf structure of this genus, and the type species was designated as M. gigas . Here we provide further details on Gray’s diagnosis and some other characters to differentiate Macronycteris from Hipposideros .
All five species of Macronycteris have a frontal sac ( Hill, 1963; Happold, 2013 c) on the forehead, in a central portion behind the posterior noseleaf. It varies in shape and size from a slightly oblong to longitudinal slit, but in all species of this genus ( Fig. 4 View FIG ), as well as in ‘ H. cyclops ’, it is distinctly vertical in shape; the latter species differs notably from Macronycteris in aspects of the noseleaf ( Happold, 2013 c: Fig. 68 a and see below). The shape and size of the frontal sac shows intraspecific variation, associated with sexual dimorphism ( Andersen, 1906), being more developed in males of at least three out of the five species now placed in this genus. The structure opening reaches its maximum length of 9 mm in M. gigas , which is the largest species in the genus (see below). In M. commersonii M. gigas and M. vittatus , the frontal sac and the distal portion of the forehead is covered with fine hair ( Fig. 4 View FIG ), although in large males of at least M. gigas it can be largely naked.
The noseleaves of Macronycteris have several particular structures, that when taken together separate them from all other genera of hipposiderids. The lateral fleshy leaflets number 4 and occasionally 3 ( Fig. 4 View FIG ). Most species of Hipposideros either lack the leaflets or have a maximum of 2, the exceptions being H. abae , H. alongensis , H. cervinus (apparently in some cases only 2), H. dinops , H. larvatus , H. lekaguli and H. speoris with up to three leaflets and H. armiger , H. diadema , H. griffini , H. lankadiva , H. papua , H. pendleburyi and H. turpis with four leaflets ( Andersen, 1905, 1906; Payne et al., 1985; Strahan, 1995; Flannery, 1995 a, 1995 b; Bates and Harrison, 1997; Francis, 2008; Thong et al., 2012 a, 2012 b; Happold, 2013 c); in all cases these species have other morphological aspects of the noseleaves that separate them from members of the genus Macronycteris . Further, the largely unornamented noseleaves of Macronycteris include the following characters: 1) anterior portion is broad and without any median modifications, internarial septa form small and narrow structures not obscuring the slightly deep-set nasal passages, and small but distinct lappets surround the nasal passages; 2) middle portion of noseleaf is simple, slightly expanded and lacking other structures; and 3) posterior portion of noseleaf without lateral process or other adornment, with a vertical medial septum, and two prominent vertical lateral septa, which divide the structure into four separate cells. (These three septa in some cases are not prominent and poorly defined.) The different aspects of the noseleaf and forehead pore are unique to Macronycteris and are not found in any other genus of the family Hipposideridae ( Rosevear, 1965; Payne et al., 1985; Flannery, 1995 a, 1995 b; Bates and Harrison, 1997; Francis, 2008; Monadjem et al., 2010; Happold, 2013 c).
The separated ears in Macronycteris are constricted towards the base, triangular in shape and with pointed distal tips and curved posterior margins that give a limp or droopy appearance. The ear length average in M. commersonii 29.6 mm (♂♂, n = 27) and 28.8 mm (♀♀, n = 76), in M. cryptovalorona 26 mm and 27 mm (n = 2), in M. gigas 31.4 mm (sexes combined, n = 34) and in M. vittatus 29.5 mm (sexes combined, n = 95) ( Happold, 2013 c; Goodman et al., 2016). Antitragus not notably developed. The genus is the largest amongst living hipposiderids, often showing sexual dimorphism in external measurements. The size of these animals can be best expressed by mean forearm length, which in M. commersonii is 90.7 mm (♂♂, n = 27) and 86.4 mm (♀♀, n = 76), in M. cryptovalorona 80 and 81 mm (n = 2), in M. gigas 107.9 mm (♂♂, n = 39) and 103.8 (♀♀, n = 39), in M. thomensis 79–82 mm (n = 3) and in M. vittatus 101.5 mm (♂♂, n = 78) and 93.9 (♀♀, n = 58) ( Andersen, 1906; Happold, 2013 c; Goodman et al., 2016). The only Hipposideros approaching the size of Macronycteris are H. dinops from Papua New Guinea with a forearm of 93.3 mm (♂♂, n = 3) and 91.6 mm (♀♀, n = 5) and H. inexpectatus from northern Sulawesi with a forearm of 100.8 mm ( Laurie and Hill, 1954; Flannery, 1995 b). All species of Macronycteris have relatively dense and short fur, with a mixture of rich fawn to rufus on the dorsum and slightly lighter ventrum, and distinctive white fur on the shoulders; certain species have a distinct rufus-orange colour phase. The unfurred wing and tail membranes are pale to dark brown. The tail is distinctly shorter than the length of the extended hind foot. The plagiopatagium attaches at approximately ankle level.
The skull of the different members of Macronycteris are notably large, with very pronounced lambdoid and sagittal crests, being more developed in adult males and in M. gigas , the largest member of the genus. The zygomatic arches are robust and form the widest portion of the skull. The rostrum is notably wide and in dorsal view the naso-frontal portion of the skull has a distinct pentagonal shape. The mandible is notably large, with a deep symphysis, large angular process and elevated coronoid process.
Dentition notably massive, clearly indicative of a powerful bite for subduing prey. Dental formula — premolars 1/2, canines 1/1, premolars 2/2 and molars 3/3. The upper incisors are widely spaced on the outer portion of the premaxillae and in fresh adult dentitions weakly lobed. The upper canine is massive and in direct contact with the second upper premolar, with the first upper premolar being small and external to the toothrow. The upper canine is grooved and with a distinct cusp on the upper posterior edge. In general, cusp structure of premolars and molars similar to large members of the genus Hipposideros following the description of Miller (1907).
Karyological characters
On the basis of karyological information from the literature, further evidence can be found for the resurrection of the genus Macronycteris for species formerly placed in the commersonii group. Hipposideros is characterised by its extreme karyological conservatism, with nearly all species examined so far having a 2 n complement of 32 ( Harada et al., 1982; Hood et al., 1988; Rautenbach et al., 1993; Bogdanowicz and Owen, 1998; Koubínová et al., 2010; Mao et al., 2010; Porter et al., 2010). However, Macronycteris taxa, previously attributed to Hipposideros , differ markedly from this conserved karyotype with M. commersonii s.l., M. commersonii s.s. and M. gigas having 2 n = 52 ( Rautenbach et al., 1993; Koubínová et al., 2010), as well as M. commersonii s.s. having chromosome characters unlike those in Hipposideros ( Richards et al., 2016) . The exception to the n = 32 complement for members of the genus Hipposideros is ‘ H. cyclops ’ having 2 n = 36 ( Koubínová et al., 2010); herein we present evidence that this species is best placed in the genus Doryrhina (see below).
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