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A new genus of ambrosia beetle from Melanesia (Coleoptera: Curculionidae: Scolytinae: Xyleborini)

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A new genus of xyleborine ambrosia beetle, Melanesicus Beaver Petrov gen. n., with type species Xyleborus partitus Browne (1974) is described from the Melanesian region. The following new combinations are proposed: M. caledoniae (Beaver Liu, 2016) comb. n., M. deformatus (Browne, 1974) comb. n., M. granulosus (Schedl, 1975) comb. n., all from Xyleborus Eichhoff, 1864. Melanesicus tishechkini Petrov sp. n. is described from Vanuatu, and Melanesicus nukuruanus sp. n. Beaver from Fiji. The taxonomy, distribution and biology of the species included are briefly reviewed.
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ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Accepted by S. Smith: 11 Feb. 2021; published: 24 Mar. 2021 163
Zootaxa 4949 (1): 163–172
https://www.mapress.com/j/zt/
Copyright © 2021 Magnolia Press Article
https://doi.org/10.11646/zootaxa.4949.1.9
http://zoobank.org/urn:lsid:zoobank.org:pub:4A8E4749-DCAB-4A6B-A5D0-0812DE0EDF6E
A new genus of ambrosia beetle from Melanesia (Coleoptera: Curculionidae:
Scolytinae: Xyleborini)
R. A. BEAVER1*, A. V. PETROV2 & W. SITTICHAYA3
1161/2 Mu 5, Soi Wat Pranon, T. Donkaew, A. Maerim, Chiangmai 50180, Thailand.
rogerbeaver6@gmail.com; https://orcid.org/0000-0003-1932-3208
2Institute of Forest Science RAS, Sovetskaya st. 21, Uspenskoe, Moscow Region 143030, Russia.
hylesinus@list.ru; https://orcid.org/0000-0001-9448-7179
3Agricultural Innovation and Management Division, Faculty of Natural Resources, Prince of Songkla University, Hat Yai, Songkhla,
90112, Thailand.
wanakorn62@hotmail.com; https://orcid.org/0000-0001-6200-1285
*Corresponding author.
Abstract
A new genus of xyleborine ambrosia beetle, Melanesicus Beaver & Petrov gen. n., with type species Xyleborus partitus
Browne (1974) is described from the Melanesian region. The following new combinations are proposed: M. caledoniae
(Beaver & Liu, 2016) comb. n., M. deformatus (Browne, 1974) comb. n., M. granulosus (Schedl, 1975) comb. n., all from
Xyleborus Eichhoff, 1864. Melanesicus tishechkini Petrov sp. n. is described from Vanuatu, and Melanesicus nukuruanus
sp. n. Beaver from Fiji. The taxonomy, distribution and biology of the species included are briefly reviewed.
Key words: ambrosia beetle, Melanesia, new genus, new species, new combinations
Introduction
Ambrosia beetles are weevils in the subfamilies Scolytinae and Platypodinae which bore into the wood of dead or
dying trees or branches (rarely living ones) and cultivate symbiotic ambrosia fungi on the walls of the gallery system
they have constructed (Kirkendall et al. 2015; Biedermann & Vega 2020). The fungi are used as food by both adults
and larvae. The ambrosia beetle habit has evolved more than 10 times within the Scolytinae, but the majority of the
scolytine ambrosia beetles are placed in the tribe Xyleborini. Prior to 1980, the largest genus in the tribe, Xyleborus
Eichhoff, 1864, included over 1,000 described species. Wood (1980) began the process of splitting up this very
large genus, describing six new genera. Later, Wood (1986) revived a number of genera which had been described
by Reitter (1913), Hopkins (1915), and others, but synonymised within Xyleborus by Schedl (1963). Further genera
have been revived by Hulcr et al. (2007), and Mandelshtam et al. (2019), and new genera described by Hulcr and
Cognato (2009, 2010), Smith (2017), Cognato (2018), Cognato et al. (2020), and Sittichaya & Smith (2020). In this
paper, we add one more new genus for a small group of species, formerly included in Xyleborus. Two new species
are described, and a key to species is provided. The species are found only in the Melanesian region from New
Guinea to Fiji.
Material and Methods
The paper is based on the study of types and other specimens in the Natural History Museum, London (NHML),
and the Naturhistorisches Museum, Vienna (NMW), specimens sent to the senior author for identification by the
Queensland Museum, Brisbane, and by the Fiji Forestry Department, Colo-i-Suva, and specimens collected by the
senior author on Viti Levu (Fiji), and Alexey K. Tishechkin in New Caledonia and Espiritu Santo Is. (Vanuatu).
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Photographs were taken by A. Petrov using a Canon 50D camera and a MP-e65 mm macro lens, and by W. Sit-
tichaya using a Canon 6D camera, a MP-e65 mm macro lens and Canon Extender EF 2.0x III.
The following abbreviations are used for collections
APP Alexander V. Petrov private collection, Moscow, Russia
MNHN Muséum National d’Histoire Naturelle, Paris, France
NHML Natural History Museum, London, U.K.
NMW Naturhistorisches Museum, Vienna, Austria
QMB Queensland Museum, Brisbane, Australia
RAB R. A. Beaver’s private collection, Chiang Mai, Thailand
ZMMU Zoological Museum at Moscow State University, Moscow, Russia
Genus Melanesicus Beaver & Petrov, gen. n.
Type species: Xyleborus partitus Browne 1974: 69.
Diagnosis. The genus Melanesicus clearly belongs in the tribe Xyleborini (Wood 1986; Alonso-Zarazaga & Lyal
2009). It is distinguished morphologically from other genera in the tribe by the following combination of charac-
ters: 1) antennal funicle 4-segmented (excluding pedicel), club of type 3 (Hulcr et al. 2007; Smith et al. 2020); 2)
pronotum subquadrate in form as viewed from above, as wide as or slightly wider than long, the anterior margin
transverse, without asperities, emarginate in the middle when viewed from in front, lacking mycangial tufts at
the base; 3) scutellum linguiform, flush with the surface of the elytra or almost so; 4) elytra divided into sharply
separated smooth and shining (anterior), and matt (posterior) areas, the latter armed with numerous granules; 5)
sclerolepidia absent from dorsal margin of metaventrite; 6) procoxae contiguous; 7) protibiae subtriangular, wid-
est at apical third, the outer margin with 7‒13 small, closely set, socketed teeth in apical two-thirds, the posterior
surface without granules.
Description. Female. Antenna with antennal funicle 4-segmented (excluding pedicel), first segment of club
occupying one-third to one half of anterior face, its anterior margin concave or sinuate, segment 2 corneous, two
sutures visible on posterior face. Eyes coarsely faceted, shallowly to strongly emarginate, upper part smaller than
lower part or approximately equal in size. Frons plano-convex, usually with a median, smooth, shining, almost im-
punctate area extending from anterior margin to upper margin of eyes. Submentum triangular, impressed.
Pronotum subquadrate, as wide as or a little wider than long, anterior angles strongly curved, anterior margin
almost transverse, without asperities, emarginate in middle when viewed from in front; anterior slope weakly im-
pressed in middle near anterior margin, armed with very numerous, tiny, pointed asperities, which become more
transversely elongate towards summit in middle of pronotum; disc smooth, subnitid or dull, finely, not very densely
punctured. Scutellum linguiform to triangular, shining, flush with elytral surface or almost so.
Elytra 1.5‒1.6 times longer than wide, 1.45‒1.8 times as long as pronotum; viewed from above sharply divided
into basal smooth, shining, and apical, matt, granulate parts (a deep, saddle-like transverse impression just before
declivity in one species); basal part bearing fine strial and interstrial punctures, the serial arrangement rather indis-
tinct; declivity strongly convex, with granules on striae and interstriae, or only on interstriae, or without a distinct
arrangement; interstriae 1 broadened and raised at least near apex of declivity, bearing larger granules and projecting
beyond apex in lateral view. Metanepisternum narrow with one or two rows of seta-bearing punctures. Metaventrite
without a row of sclerolepidia on dorsal margin.
Legs with procoxae contiguous, sternellum swollen, protibiae subtriangular with numerous (7‒13), small,
closely set, socketed teeth in apical two-thirds, the posterior surface without granules. Meso- and metatibiae flat-
tened, strongly widened in middle, with numerous, small, socketed teeth.
Male. The male has been described only for M. caledoniae (Beaver & Liu 2016). It is generally similar to the
female, but smaller and stouter, the eyes are reduced, the pronotum relatively wider, and the elytra relatively shorter.
The sculpture of the matt area of the elytra differs in detail from that of the female.
Distribution. The genus is distributed in the Melanesian region from New Guinea to Vanuatu, New Caledonia
and Fiji.
Relationships. There is a superficial resemblance to Schedlia Browne, 1950, in the quadrate shape of the
pronotum with a transverse anterior margin, and the division of the elytra into anterior shining, and posterior matt
NEW SCOLYTINE GENUS MELANESICUS Zootaxa 4949 (1) © 2021 Magnolia Press · 165
and granulate parts, but Melanesicus has a distinct flat scutellum, and the posterior surface of the protibiae is not
granulate. In Schedlia, the scutellum is not visible, the protibiae are granulate posteriorly, and mycangia are present
in the elytral bases (Hulcr & Cognato 2013). The position of the mycangia in Melanesicus is not certain, but they
are probably oral. The only species of Melanesicus in which DNA has been investigated (M. granulosus) grouped in
a weakly supported clade with a species of Ancipitis Hulcr & Cognato, 2013 (Cognato et al. 2011, 2020). However,
the relationship of the two genera seems likely to be distant. As noted by Hulcr & Cognato (2013), Ancipitis has a
number of dryocoetine-like characters including a flat submentum, a long ventral side to the head, and narrow tibiae
with few large denticles in enlarged sockets, characters which are absent in Melanesicus.
Biology. The biology of Melanesicus has been investigated only in M. partitus and M. deformatus (Roberts
1977). The gallery system consists of multiply branched tunnels in one transverse plane. The eggs are laid in
clutches, initially of 4 to 6, but later of up to 12 or 14, in the branches, and the larvae of each batch appear to de-
velop and pupate within the branch in which they hatched. The adults of the new generation move around the nest,
and undergo a period of maturation feeding within the nest before emergence. Brood sizes in mature galleries can
be very large (at least 150 individuals) in M. partitus, but only smaller broods were observed in M. deformatus. The
males develop faster than the females. Roberts (1977) found a sex ratio of 4−7 females: 1 male in young broods, but
it is likely that the ratio increases in older galleries.
The occurrence of maturation feeding within the parental gallery by the new generation females implies the
possibility that they are also involved in brood care, gallery maintenance and fungal gardening (Biedermann & Ta-
borsky 2011; Biedermann et al. 2011). Given the large size of some gallery systems of M. partitus investigated by
Roberts (1977), it is also possible that some may breed within the parental nest rather than dispersing to found new
nests (Biedermann et al. 2012).
Key to Melanesicus species (females)
1 Elytra strongly, transversely impressed just before declivity. Declivity almost vertical with two rows of small, stout, pointed
teeth on upper margin. 2.9‒3.1 mm long. Fiji. ..............................................deformatus (Browne)
Elytra not strongly impressed before declivity. Declivity less strongly sloping, without rows of pointed teeth on upper margin.
...................................................................................................2
2 Granules on elytral declivity arranged in uniseriate rows along striae and interstriae, or on interstriae alone. .............3
Granules on elytral declivity irregularly scattered over surface, at least on apical half of declivity, so that striae and interstriae
are obscured. ........................................................................................5
3 Granules on elytral declivity large, almost equal in size on striae and interstriae. 3.5‒3.75 mm long. New Caledonia. .......
...............................................................................caledoniae (Beaver & Liu)
Granules on elytral declivity smaller on striae than on interstriae or absent. .......................................4
4 Strial granules on elytral declivity minute or absent. 3.6‒3.8 mm long. Fiji. ..........................partitus (Browne)
Strial granules on elytral declivity smaller than those on interstriae, but distinct. 3.95‒4.0 mm long. Vanuatu. .............
.................................................................................tishechkini Petrov sp. n.
5 Larger species, 3.2 mm long. Granules on elytral declivity confused over whole surface, striae and interstriae obscure. New
Guinea. ..............................................................................granulosus (Schedl)
Smaller species, 2.45 mm long. Granules on elytral declivity in strial and interstrial rows near upper margin, becoming con-
fused in apical half of declivity. Fiji. .................................................. nukuruanus Beaver sp. n.
Descriptions of new species
Melanesicus tishechkini Petrov sp. n.
(Figs 1‒4)
Female.
Body. 3.95‒4.0 mm long, 2.63 times longer than wide, reddish-brown, darker towards apex of elytra, pronotal
summit, and ventrites.
Head. Frons broad, plano-convex, weakly shining, moderately densely, rather coarsely punctured, with a me-
dian shining, almost impunctate area extending from epistoma to vertex, rugulose at sides next to eyes; surface of
frons covered by sparse erect setae, epistoma above mandibles with a row of numerous yellow setae; eyes shallowly
emarginate, coarsely faceted; antenna of type 3 (Hulcr et al. 2007), funicle 4-segmented (excluding pedicel), first
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segment of club covering more than half of anterior face, its anterior margin concave, second segment corneous,
two sutures visible on posterior face.
Pronotum. Subquadrate, 0.96 times as long as wide, basal angles almost rectangular, sides widest at middle,
weakly, evenly curved to anterior angles where sharply curved to anterior margin, the latter almost transverse when
viewed from above, weakly emarginate in middle when viewed from in front, without asperities; anterior slope
with very numerous, tiny, pointed, closely placed asperities, each with a semi-erect seta arising posteriorly, asperi-
ties more closely placed and more transversely elongate towards summit, but not extending behind it; summit in
middle of pronotum, extending transversely for about one quarter of width of pronotum; surface of elytral disc dull
to weakly shining, moderately densely, finely punctured, the punctures with short, fine, semi-erect setae, coriaceous
between punctures.
Scutellum. Linguiform, rounded above.
Elytra. 1.55 times longer than wide, 1.53 times longer than pronotum, viewed from above abruptly divided
into a basal shining area extending one third of elytral length near suture, and a matt area extending to apex; at sides
shining area extends posteriorly up to interstriae 7; viewed from side, basal part of elytra slightly rising posteri-
orly to junction with matt area, very weakly impressed just behind junction, then level to beginning of declivity in
posterior third; strial and interstrial punctures confused and indistinct on basal shining area, matt area of disc with
punctures replaced by very small granules on striae and lager granules on interstriae, twice as large as those in striae
on base of matt area, and granules on striae four times larger on apical part of elytra; interstriae 1 broadened and
raised near apex of declivity, the raised part projecting beyond the apex in lateral view, and with some irregularly
placed small spines of varied size; lateral margin of declivity carinate to interstriae 7 with small pointed granules;
discal striae with short, fine setae, striae and interstriae on matt area with slightly stouter, erect setae arising from
behind granules.
Metanepisternum. Narrow with longitudinal carina and one row of punctures bearing semi-erect setae.
Metaventrite without a row of sclerolepidia on dorsal margin.
FIGURES 1‒4. Melanesicus tishechkini sp. n. female. 1. Dorsal view; 2. Lateral view; 3. Postero-lateral view of elytra; 4.
Anterior view of head.
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Legs. Procoxae subcontiguous, sternellum moderately swollen, protibiae weakly wider at apical third, outer
margin with 11–13 small, closely set, socketed teeth in apical two-thirds, mesotibiae flattened, strongly widened,
widest at middle, outer margin with 13–14 small teeth in apical two-thirds, metatibiae narrower than mesotibiae,
with 13–14 small teeth in apical two-thirds.
Male. Unknown.
Type material. Holotype: Female: VANUATU: Espiritu Santo Is., Cumberland peninsula, Saratsi range, 600 m
a.s.l., 14°57’50.8’’S 166°38’52.4’’E, FIT, 6.–7.XI.2006, leg. Alexey K. Tishechkin. Deposited in ZMMU.
Paratype: as holotype (in APP).
Diagnosis. The new species is closely related to Melanesicus caledoniae, but can be distinguished by the elytral
disc curving evenly into the declivity, the matt area with very small granules on the striae and larger granules on the
interstriae. Differences from the other species of Melanesicus are included in the key to species.
Etymology. This species is named in honour of its collector, Alexey K. Tishechkin, avid beetle collector, who
collected the holotype and paratype in Vanuatu.
Melanesicus nukuruanus Beaver sp. n.
(Figs 5‒8)
Female.
Body. 2.45 mm long, 2.45 times longer than wide, yellowish brown, posterior part of elytral disc and declivity
darker, reddish-brown, legs and underside except abdomen pale yellow, abdomen light brown.
Head. Frons broad, plano-convex, weakly shining, moderately densely, rather coarsely punctured, the punc-
tures with moderately long, erect hair-like setae, a slightly raised, impunctate median area extending from epistoma
to middle of eyes; eyes shallowly emarginate, coarsely faceted; antennae of type 3 (Hulcr et al. 2007), funicle 4-
segmented (excluding pedicel), first segment of club covering about one-half of club, its anterior margin sinuate,
second segment corneous, two sutures visible on posterior face.
Pronotum. Almost square in shape, as wide as long, basal angles angularly rounded, sides evenly curved, wid-
est at middle, anterior angles sharply curved to anterior margin, the margin almost transverse with a weak median
emargination when viewed from above, distinctly, broadly emarginate when viewed from in front, without asperities
on margin; anterior slope with very numerous, tiny, pointed, closely placed asperities, each with a semi-erect seta
arising posteriorly, asperities more closely placed and more transversely elongate towards summit, but not extending
behind it; summit in middle of pronotum, extending transversely for about one quarter of width of pronotum; elytral
disc dull, coriaceous, moderately densely, finely punctured, the punctures with short, erect or semi-erect, fine setae.
Scutellum. Linguiform, flush with surface of elytra.
Elytra. 1.49 times longer than wide, 1.45 times longer than pronotum, sides parallel in basal four-fifths, then
curved to slightly angulate apex; viewed from above abruptly divided into a basal shining area extending one half
of elytral length near suture, and a matt declivital area extending to apex; at sides, shining area extends to interstriae
7; viewed from side, basal part of elytra rises slightly to junction with matt area; on elytral disc, punctures equally
sized, fine, with strial and interstrial rows not clearly distinct; on declivity, strial and interstrial punctures replaced
by small granules, decreasing in size and elevation in middle of declivity, but increasing again in size and elevation
close to apex; interstriae 1 slightly raised close to apex, and with stronger granules; granules in rows near the upper
margin of the declivity, confused in the middle part from the suture to striae 3, more regularly seriate on interstriae 3
and striae 4, then confused on outer striae and interstriae; lateral margin of declivity carinate to interstriae 7; discal
striae with short, fine setae, declivital striae and interstriae with stouter, erect setae arising behind granules.
Metanepisternum. Narrow with two irregular rows of punctures bearing semi-erect setae.
Metaventrite without a row of sclerolepidia on dorsal margin.
Legs. Procoxae contiguous, sternellum slightly swollen, protibiae weakly expanded in apical half, outer margin
with 7 small, socketed teeth in apical half, mesotibiae flattened, strongly widened, outer margin with 10 small teeth
in apical two-thirds, metatibiae narrower than mesotibiae with 11 small teeth in apical two-thirds.
Male. Unknown.
Type material. Holotype: Female: FIJI: Viti Levu, Nukurua, Light Trap, 7.iv.1987, DS‒130 [no collector]. Cur-
rently in RAB, to be deposited in NHML.
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Diagnosis. The new species is similar to M. granulosus, but can be distinguished by its smaller size, and the
granules on the elytral declivity in rows on the striae and interstriae near the upper margin, becoming confused in the
apical half of the declivity. Differences from the other species of Melanesicus are included in the key to species.
Etymology. The species is named after the locality where the species was collected.
FIGURES 5‒8. Melanesicus nukuruanus sp. n. female. 5. Dorsal view; 6. Lateral view; 7. Postero-lateral view of elytra; 8.
Anterior view of head.
Notes on species
The purpose of these notes is to provide information on the other species which we consider to be included in Mela-
nesicus. Information is given on their taxonomy, distribution and biology.
NEW SCOLYTINE GENUS MELANESICUS Zootaxa 4949 (1) © 2021 Magnolia Press · 169
Melanesicus caledoniae (Beaver & Liu) comb. n.
Xyleborus caledoniae Beaver & Liu 2016: 26.
Taxonomy. The senior author has examined the holotype (MNHN) and paratypes (QMB, RAB). A. Petrov has
examined a further specimen from New Caledonia. The species is distinguished from other species of Melanesicus
primarily by its elytral sculpture (see key above, and Beaver & Liu 2016).
Distribution. The species is endemic to New Caledonia.
New record: NEW CALEDONIA: S-Prov. Refuge de Plano, 2 km NNE Farino, 21°38’55’’S 165°46’53’’E, ca.
270 m, at light, 28.-30.XI.2009, Schuh (1) (APP).
Biology. Unknown.
Remarks. Photographs of female and male are included in Beaver & Liu (2016, Figs 5‒8).
Melanesicus deformatus (Browne) comb. n.
(Figs 9‒10)
Xyleborus deformatus Browne 1974: 70.
Taxonomy. The senior author has examined the holotype and paratypes (NHML) and specimens in RAB. The spe-
cies is easily distinguished by the strong, saddle-shaped impression of the elytral disc just before the declivity.
Distribution. The species is endemic to Fiji, where it occurs only in the higher altitude rain forest (Roberts
1977).
FIGURES 9‒10. Melanesicus deformatus (Browne) female. 9. Dorsal view; 10. Lateral view.
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Biology. Roberts (1977) described the biology of the species, including the gallery system, development, brood
sizes, and notes associated species of Scolytinae and Platypodinae, as well as nest parasites (Cyphagogus fijianus
Kleine) (Coleoptera: Brentidae). He recorded the species most frequently from Dysoxylum spp. (Meliaceae), but
also from single host trees in three other families (Roberts 1977). RAB collected the species only from Dysoxylum
sp., and it appears to have a strong host preference for this genus. In contrast to M. partitus (see below), the adults
emerge around dusk, and are strongly attracted to light (Roberts 1977).
Melanesicus granulosus (Schedl) comb. n.
Xyleborus granulosus Schedl 1975: 366.
Taxonomy. The holotype (NMW) has been examined by RAB. The species was synonymised with Xyleborus par-
titus by Schedl (1980), but restored as a distinct species by Beaver (1991). Hulcr and Cognato (2013) diagnosed the
species, recognised that it could not be included in Xyleborus sens. str., and included it under ‘Xyleborini, incertae
sedis’. Cognato et al. (2020) in their phylogeny of 181 xyleborine species, showed that it lay on a branch distinct
from Xyleborus. The species is distinguished from other species of Melanesicus apart from M. nukuruanus, by the
lack of distinct striae, and the irregular arrangement of granules on the elytral declivity.
Distribution. The species is endemic to New Guinea.
Biology. Unknown.
Remarks. A photograph of a female specimen is available at http://www.ambrosiasymbiosis.org .
FIGURES 11‒12. Melanesicus partitus (Browne) female. 11. Dorsal view; 12. Lateral view.
NEW SCOLYTINE GENUS MELANESICUS Zootaxa 4949 (1) © 2021 Magnolia Press · 171
Melanesicus partitus (Browne) comb. n.
(Figs 11‒12)
Xyleborus partitus Browne 1974: 69.
Taxonomy. The senior author has examined the holotype and a paratype (NHML), and specimens in RAB. Schedl
(1980) considered that Xyleborus granulosus was a synonym of this species, but the two species were distinguished
by Beaver (1991).
Distribution. The species is endemic to Fiji, where it occurs in both high and low altitude rain forest (Roberts
1977).
Biology. Roberts (1977) described in detail the gallery system, brood size and development, and noted associ-
ated species of ambrosia beetles. He recorded the species from nine different families of host trees (Roberts 1977).
It is evidently polyphagous. In contrast to M. deformatus (see above), emergence is probably confined to the day,
and the species was never taken at light (Roberts 1977).
Acknowledgements
We are most grateful to the following for the loan of specimens and access to the collections in their charge: M.
Barclay (NHML), E. Guilbert (MNHN), H. Schönmann† and H. Schillhammer (NMW), G. B. Monteith (QMB),
M. Kamath (Fiji Forestry Dept., Colo-i-Suva). A.V. Petrov expresses his most sincere gratitude to Dr. Alexey K.
Tishechkin (California Department of Food and Agriculture, Sacramento, California, USA) for providing material
from Melanesia.
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... Asia and Pacific islands are diverse with xyleborine ambrosia beetles. For example, 35 genera and 323 species have been identified for Indo-China, China, and the Eastern Himalayan Region Lin & Smith 2022;) and at least 144 species in 33 genera occur in New Guinea (Hulcr & Cognato 2013;Cognato et al. 2020a;Smith et al. 2020b;Beaver et al. 2021). At a minimum, 30% of the fauna remains undescribed because the region is generally under collected for scolytines . ...
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Eighteen xyleborine ambrosia beetles are described and illustrated: Anisandrus proscissus Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Anisandrus simplex Smith, Beaver & Cognato sp. nov. (Nepal), Arixyleborus belalongi Smith, Beaver & Cognato sp. nov. (Brunei Darussalam), Beaverium brevicaudatus Smith, Beaver & Cognato sp. nov. (Indonesia), Cnestus luculentus Smith, Beaver & Cognato sp. nov. (India), Cyclorhipidion achlys Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Cyclorhipidion conidentatus Smith, Beaver & Cognato sp. nov. (Indonesia), Cyclorhipidion gladigerum Smith, Beaver & Cognato sp. nov. (Thailand), Cyclorhipidion lapilliferum Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Cyclorhipidion nepalense Smith, Beaver & Cognato sp. nov. (Nepal), Cyclorhipidion taedulum Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Cyclorhipidion titorum Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Euwallacea alastos Smith, Beaver & Cognato sp. nov. (Japan), Leptoxyleborus regina Smith, Beaver & Cognato sp. nov. (Papua New Guinea), Tricosa hipparion Smith, Beaver & Cognato sp. nov. (Malaysia), Xyleborinus acanthopteron Smith, Beaver & Cognato sp. nov. (Thailand), Xyleborinus dumosus Smith, Beaver, Pham & Cognato sp. nov. (Vietnam), Xyleborinus nobuchii Smith, Beaver & Cognato sp. nov. (Japan). New distribution records are reported for 67 Asian species. Cyclorhipidion nemesis Smith & Cognato, described from U. S. A., is reported from Asia (China), its hypothesized native continent, for the first time. Its identity is confirmed with COI and CAD DNA within a phylogenetic analysis including other Cyclorhipidion species.
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Twenty-four new synonyms are proposed: Ambrosiophilus osumiensis (Murayama, 1934) (= Xyleborus nodulosus Eggers, 1941 syn. nov. ); Ambrosiophilus subnepotulus (Eggers, 1930) (= Xyleborus cristatuloides Schedl, 1971 syn. nov. ); Ambrosiophilus sulcatus (Eggers, 1930) (= Xyleborus sinensis Eggers, 1941 syn. nov. ; = Xyleborus sulcatulus Eggers, 1939 syn. nov. ); Anisandrus hirtus (Hagedorn, 1904) (= Xyleborus hirtipes Schedl, 1969 syn. nov. ); Cnestus protensus (Eggers, 1930) (= Cnestus rostratus Schedl, 1977 syn. nov. ); Cyclorhipidion bodoanum (Reitter, 1913) (= Xyleborus misatoensis Nobuchi, 1981 syn. nov. ); Cyclorhipidion distinguendum (Eggers, 1930) (= Xyleborus fukiensis Eggers, 1941 syn. nov. ; = Xyleborus ganshoensis Murayama, 1952 syn. nov. ); Cyclorhipidion inarmatum (Eggers, 1923) (= Xyleborus vagans Schedl, 1977 syn. nov. ); Debus quadrispinus (Motschulsky, 1863) (= Xyleborus fallax Eichhoff, 1878 syn. nov. ); Euwallacea gravelyi (Wichmann, 1914) (= Xyleborus barbatomorphus Schedl, 1951 syn. nov. ); Euwallacea perbrevis (Schedl, 1951) (= Xyleborus molestulus Wood, 1975 syn. nov. ; Euwallacea semirudis (Blandford, 1896) (= Xyleborus neohybridus Schedl, 1942 syn. nov. ); Euwallacea sibsagaricus (Eggers, 1930) (= Xyleborus tonkinensis Schedl, 1934 syn. nov. ); Euwallacea velatus (Sampson, 1913) (= Xyleborus rudis Eggers, 1930 syn. nov. ); Microperus kadoyamaensis (Murayama, 1934) (= Xyleborus pubipennis Schedl, 1974 syn. nov. ; = Xyleborus denseseriatus Eggers, 1941 syn. nov. ); Stictodex dimidiatus (Eggers, 1927) (= Xyleborus dorsosulcatus Beeson, 1930 syn. nov. ); Webbia trigintispinata Sampson, 1922 (= Webbia mucronatus Eggers, 1927 syn. nov. ); Xyleborinus artestriatus (Eichhoff, 1878) (= Xyelborus angustior [ sic ] Eggers, 1925 syn. nov. ; = Xyleborus undatus Schedl, 1974 syn. nov. ); Xyleborinus exiguus (Walker, 1859) (= Xyleborus diversus Schedl, 1954 syn. nov. ); Xyleborus muticus Blandford, 1894 (= Xyleborus conditus Schedl, 1971 syn. nov. ; = Xyleborus lignographus Schedl, 1953 syn. nov. ). Seven species are removed from synonymy and reinstated as valid species: Anisandrus cristatus (Hagedorn, 1908), Cyclorhipidion tenuigraphum (Schedl, 1953), Diuncus ciliatoformis (Schedl, 1953), Euwallacea gravelyi (Wichmann, 1914), Euwallacea semirudis (Blandford, 1896), Microperus fulvulus (Schedl, 1942), Xyleborinus subspinosus (Eggers, 1930).
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