Molecular and morphological revision of Afrotropical Hypoborini (Coleoptera: Curculionidae: Scolytinae) revealed novel bark beetle taxa with narrow geographical distributions

Species in the bark beetle tribe Hypoborini Nüsslin, 1912 occur in dead twigs and branches, mainly in dry forest. The Afrotropical fauna previously included ten species in fi ve genera. A taxonomic revision based on molecular and morphological data supports the description of three new genera and seven new species, and the creation of a new subtribe Xerasiborina Jordal, subtrib. n. in order to take account of the difference between crested and non-crested (elytral base) hypoborines. The new subtribe includes Xerasiborus Jordal, gen. n., Nisiborus Jordal, gen. n. and tentatively Glochiphorus Strohmeyer, 1910. Hypoborina in the Afrotropical region includes Dacryostactus Schaufuss, 1905, Styracoptinus Wood, 1962, Afrotrypetus Bright, 1982 stat. res., and Corditarsus Jordal, gen. n., with Hypoborus Erichson, 1836 and Liparthrum Wollaston, 1854 as geographically close members in the warm Palearctic. New species described are Xerasiborus quadrituberculatus Jordal, sp. n., Xerasiborus bituberculatus Jordal, sp. n., Xerasiborus euphorbiae Jordal, sp. n. and Xerasiborus asperatus Jordal, sp. n., all from Madagascar, Xerasiborus zambesianus Jordal, sp. n. from Tanzania, Nisiborus schaufussi Jordal, sp. n. from Madagascar and Afrotrypetus capensis Jordal, sp. n. from South Africa. New combinations include Nisiborus hylesiniformis (Schedl, 1961), comb. n. (from Cryphyophthorus Schedl, 1953), Corditarsus australis (Schedl, 1975) comb. n. (from Liparthrum), Corditarsus tanganyikaensis (Schedl, 1972) comb. n. (from Hypoborus) and Afrotrypetus euphorbiae Bright, 1981 comb. res. (from Styracoptinus). Three genera were removed from Hypoborini: Chaetophloeus LeConte, 1876 and placed in Chaetophloeini Jordal, trib. n., Zygophloeus Schedl, 1958 in Hylesinini Erichson, 1836 and Cryphyophthorus Schedl, 1953 as a genus incertae sedis. Biogeographical analyses indicate an early Palaeocene origin of Hypoborini, with an ancestral area split between Asia/Africa and Madagascar. Only a single colonization of Madagascar occurred, with a single recolonization of the African mainland. The more species-rich Mediterranean and Macaronesian radiation in Liparthrum occurred later in the Oligocene, most likely prior to the origin of the Atlantic islands. ZooBank Article Registration: http://zoobank.org/urn:lsid:zoobank.org:pub:2C8AA3C2-FEF7-40B9-9667-D484C6184A64


INTRODUCTION
Bark beetles in the tribe Hypoborini Nüsslin, 1912 mainly occur in the Afrotropical and warm Mediterranean part of the Palearctic, with some species occurring in the drier parts of the Americas and SE-Asia. None of the species are regarded as pests and most are rarely collected. As typical inhabitants of dry and sun-exposed twigs and branches it is likely they are not of interest for the average bark beetle collector. This lineage is not as species rich as another group, which shares a preference for similar habitats, the Micracidini LeConte, 1876 (see Jordal, 2021). However, they are particularly speciose in a Mediterranean lineage of Liparthrum, which radiated onto the Macaronesian islands during the Miocene (Jordal et al., 2004).
Phylogenies were reconstructed in a Bayesian framework using MrBayes v. 3.2.7 (Ronquist & Huelsenbeck, 2003). The molecular data were partitioned by codon position and gene with a GTR+G+I for all except COI third positions that had GTR+G. Morphological data were analysed with gamma distributed character variation. The analyses ran with two parallel sets of four chains with the cold chain temperature set to 0.2. Runs were completed after the standard deviation of split frequencies reached well below 0.05, and likelihoods obtained stationarity as inspected in Tracer (Rambaut et al., 2018). The same partitioned dataset was further tested in a maximum likelihood framework, using IQ-tree (Minh et al., 2020). The data were also optimized by maximum parsimony in PAUP* (Swofford, 2002), which assumes the simplest possible model of evolution (all rates equal) and chooses the trees with the fewest steps in character change.
Several new genera were discovered during recent inventories in Madagascar and southern parts of Africa. The recent collecting of fresh samples has also made it possible to test hypotheses on phylogenetic relationship using molecular markers. A new framework for the classifi cation of Hypoborini is presented here based on molecular and morphological data along with a biogeographical analysis of their origin and historical distribution.

MATERIAL AND METHODS
Specimens examined were collected mainly by the author and staff during an inventory of the biodiversity in Madagascar led by Brian Fischer at California Academy of Science (CAS). Collections from the latter have fi eld codes prefi xed by BLF. Samples were collected by dissecting beetles from dead wood, or by sifting leaf litter. Types and other material examined are deposited in the following institutions: CAS -California Academy of Science, San Francisco, USA; SAMC -Iziko (South African) Museum of Cape Town, RSA; ZMHB -Museum für Naturkunde, Humboldt-Universität, Berlin, Germany; NHMW -Naturhistorisches Museum, Wien, Austria; ZUAC -Université du Antananarivo, Madagascar; ZMUB -University Museum of Bergen, Norway.

Phylogeny
Bayesian searches ran for 2 million generations and converged quickly after 55,000 generations, with aver-age standard deviation of split frequencies reaching below 0.001 and an average potential scale reduction factor (PSRF) of 1.06. The tree topology was identical to the maximum likelihood topology from the IQ-tree analysis ( Fig. 1). Unweighted parsimony analysis (not shown) differed in the position of the SE-Asian Phloeotrypetus, which was sister to a group of non-crested hypoborines (Xerasiborina), while in all other analyses based on more complex evolutionary models it was sister to the crested Afrotropical hypoborines.
The genus Xerasiborus gen. n., in which all species have a low carina instead of a strong crest at the elytral base, was monophyletic for its three included species, but with considerable genetic variation between them. The Malagasy species described as Ptilopodius hylesiniformis Schedl, Fig. 1. Phylogeny of Hypoborini based on six gene fragments and analysed using MrBayes and IQ-tree. Node support is marked by Bayesian posterior probabilities above nodes, and ML bootstrap support values below.  Jordal et al., 2004) was run for two genes (EF-1α, COI) and showed the same deviant placement. This taxon is therefore placed in a new genus Corditarsus gen. n. Zygophloeus and Chaetophloeus did not group with Hypoborini taxa as shown in several previous phylogenetic studies (Jordal & Cognato, 2012. Parsimony analysis of morphological data resulted in a less resolved consensus tree, but with the same two taxa, and Cryphyophthorus and Glochiphorus, separate from an otherwise monophyletic Hypoborini sensu stricto (Fig. 2). It was also clear from the morphological data that Corditarsus and Phloeotrypetus deviate from other Hypoborina, and that Afrotrypetus, Styracoptinus and Dacryostactus form a strongly supported group. Bayesian analysis of the morphological data (not shown) supported only the latter clade, with the remaining taxa effectively forming a polytomy.

Internal morphology
Dissections of male genitalia revealed that the structure of the genitalia is very simple and varied little between the main clades (Figs 3, 4). All have a dorso-ventrally strongly curved aedeagus, with apophyses about as long as the penis, the tegmen is generally closed but not necessarily strongly sclerotised dorsally, and the spiculum gastrale is a simple rod, occasionally with a faint basal fork. Most variation involves the length of the manubrium as described for Liparthrum and Hypoborus (see Israelson, 1990).   The proventriculus is also relatively simple compared to other Scolytinae (Figs 5-8). The anterior plate is longitudinally divided by a median suture, with at least irregular transverse rows of a few rounded teeth or granules. Hypo bo rus, Liparthrum, Styracoptinus, Dacryostactus and Afrotrypetus differ from other genera by having a closed median suture (Fig. 5). Genera in Xerasiborina subtr. n., but also Phloeotrypetus and Corditarsus, have a more open median suture (Figs 6-8).
The postnotum is separated from the metanotum and the scutoscutellar suture follows the scutellar groove for most of its length in all genera that are here included in Hypoborini. Chaetophloeus has a curved scutoscutellar suture, which quickly deviates from the groove, and the postnotum is fused to the metanotum (Israelson, 1990). Zygophloeus has a complete membrane separating the postnotum. Both genera have a toothed interlocking system on the mesal fl ange of the elytra near the scutellum, particularly so in Zygophloeus, while all true Hypoborini have a smooth and non-toothed fl ange.

Biogeography
The Beast analysis resulted in a minimum (crown) age of 58.3 Ma for Hypoborini, 48.8 Ma for Hypoborina, and 46.4 Ma for the Malagasy clade named Xerasiborina (Fig.  9). RASP analyses based on BBM optimization gave the same result as DIVA-like and DEC analyses with the jump parameter added to the biogeographical model. All these analyses inferred vicariance in conjunction with dispersal. Ancestral distributions during the Palaeocene were ambiguously inferred. Several younger events were strongly supported, including a single colonization of Madagascar in the mid-Eocene or earlier, with recolonization of the African mainland known only from a single event in the Oligocene. The Eocene was also the time of origin of African hypoborines, with a more recent radiation occurring northwards into the Mediterranean and Macaronesian region no later than the onset of the Miocene.

Tribus Hypoborini Nüsslin, 1911
Type genus. Hypoborus Erichson, 1836. Diagnosis. Eyes entire, oval to elongated. Scapus elongated, much longer than funiculus, funiculus 3-5 segmented, club fl attened, smooth and glabrous to largely pubescent, often with weakly marked sutures. Pronotum granulated or asperate on at least the anterior half, often with larger asperities on median third; pronotal vestiture consisting of mixed hair-like and scale-like setae; scutellum not clearly visible from above. Elytral base at least with a small irregular rim, more often with crenulations near scutellum; interstrial setae usually scale-like, mainly in single rows, strial setae fi ne, recumbent, rarely a dense ground vestiture consisting of short scales. Procoxa contiguous; mesocoxae broadly separated. Protibiae narrow, with 1-4 socketed teeth on their lateral and apical margins, the inner mucro rather long, curved posterolaterally; mesoand metatibiae narrow, with 2-5 fi ne, socketed, lateral teeth on apical one-third or less. Setae on metanepisternum scale-like or plumose, running in a parallel with the sclerolepidia, posteriorly turning dorsally on the epimeron and usually also ventrally just anterior to the metacoxa. Hindwings with clusters of 1, 3 or 5 setae on the subcosta, 2 or 3 on radial cell (pterostigma). Postnotum separated from metanotum by a membrane. Scutoscute llar suture straight, parallel with the scutellar groove. Proventriculus with median longitudinal suture on the anterior plate, suture closed or wide open, tubercles rounded, in irregular rows, sometimes large sutural teeth present. Male genitalia dorsoventrally strongly curved, apophyses about as long as penis, tegmen closed, occasionally weakly sclerotized dorsally, manubrium distinct, often long and curved like apophyses, spiculum gastrale a simple rod.
Excluded genera: Chaetophloeus LeConte, 1858, Cryphyophthorus Schedl, 1953, Zygophloeus Schedl, 1958 Remarks. Species of Hypoborini are morphologically similar to, but phylogenetically very distant from, Micracidini. They share features of their protibiae and digestive  system (mouthparts and proventriculus), especially with the Afrotropical members of that tribe. They can nevertheless be readily distinguished by the pattern of setae on the metanepisternum, hidden scutellum and elevated base of elytra. Previous phylogenetic analyses indicate a Cretaceous age for Micracidini and possibly Hypoborini , which may explain the limited phylogenetic resolution with respect to putatively close relatives.
Three genera are here excluded from Hypoborini. Another genus, Glochiphorus, was not investigated in sufficient detail given the limited material available (no dissections) and therefore only tentatively included in the tribe (see below). -Setae on all interstriae in single rows; elytral tubercles absent (Fig. 19); antennal club with transverse sutures lightly indented and marked by setae (Fig. 23 Diagnosis. Pronotal asperities larger on median third of anterior half, only small granules present on lateral areas. Elytral base with crest of 5-9 vertical teeth between scutellum and interstriae 4. Hindwings with a cluster of 3 setae on subcosta. Proventriculus usually with closed median suture on anterior plate, occasionally narrowly open. Included genera: Afrotrypetus Bright, 1981 stat. res., Corditarsus Jordal, gen. n., Dacryostactus Schaufuss,1905, Hypoborus Erichson, 1836, Liparthrum Wollaston, 1854, Phloeotrypetus Wood, 1960, Styracoptinus Wood, 1962, Trypanophellos Bright, 1982 Remarks. This subtribe includes the majority of taxa originally placed in this tribe, except Chaetophloeus, which is radically different not only in internal characters but also in several external features such as the protibia and antennal club. The primary defi ning feature of Hypoborina is the basal elytral crest of equally long vertical teeth between interstriae 1 and 4. Diagnosis. Antennal funiculus 5-segmented, last segment laterally strongly extended; club with three barely visible transverse sutures marked by scattered setae. Base of elytra with all teeth equally separated; vestiture consisting of irregular strial rows of recumbent, bristle-like setae, and much longer, erect, bristle-like interstrial setae, mainly on odd-numbered interstriae. Pro-and mesotibiae with fi ne to coarse hair-like setae.  (Schedl, 1977). This species is thought to be invasive (Haack, 2001) and is widespread in warm temperate and arid subtropical climates, feeding on dead Ficus branches (Israelson, 1990). Another species described in this genus, H. tanganyikaensis, differs in that funicular segment 5 is less extended laterally, all interstrial setae are short and scale-like, and the setae along the lateral edges of the tibia scale-like, and is therefore transferred to Corditarsus gen. n.

Diagnosis.
Antennal funiculus 4-segmented, last segment slightly wider than other segments; club variable, often smooth, sometimes with one or two faint sutures marked by scattered setae. Base of elytra with raised teeth variably spaced; vestiture consisting of regular strial rows of recumbent, fi ne setae, and longer erect scale-like or bristle-like interstrial setae in rows, occasionally with multiple confused rows of bristle-like setae. Pro-and mesotibiae with fi ne to coarse hair-like setae.
Included species: 36 species, but none present in the Afrotropical realm.
Remarks. All Macaronesian and Mediterranean species form a monophyletic group, which includes the type species of Liparthrum (Jordal et al., 2004). Some undescribed species in SE-Asia are similar to Liparthrum palauensis (Wood, 1960), a species originally described in the genus Phloeotrypetus Wood, which is currently placed as a synonym in Liparthrum (Wood & Bright, 1992) but restored here (see below). Molecular data (Fig. 1) and the structure of the proventriculus strongly indicate that this particular lineage is not part of Liparthrum and that a taxonomic revision of the SE-Asian and North American species, including Trypanophellos, is required.

Included species: Corditarsus australis
Distribution. Known from South Africa and Tanzania. Remarks. Molecular data support a position of C. australis separate from other Liparthrum and Hypoborus. This species also differs in that the median suture on proventriculus is open, the antennal club has a single transverse suture and there are intermixed scale-like setae on the abdominal ventrites. The peculiar heart-shaped third tarsal segment and broad scale-like setae along the lateral edge of the tibiae are unique features in Hypoborini.
Host plant. C. australis is recorded for the fi rst time from Virgilia (Fabaceae) in which it makes small cave-like egg-tunnels. The male leaves the nest early while females were found alone with young broods. This species was previously collected from another genus of Fabaceae, Lonchocarpus, in the Kruger National Park (Schedl, 1975). Remarks. Wood (1983) erroneously synonymized Afrotrypetus with Styracoptinus, arguing that A. euphorbiae intergrades with the three known species of the latter genus. This is not the case. All three Styracoptinus species have antennal clubs with two procurved sutures and a long tuft of fi ne setae on the scapus. In addition, they have tubercles and spines on the elytra, which are absent in Afrotrypetus. Diagnosis. Antennal funiculus 3-segmented, club with two transverse sutures. Plumose setae sparse on median three quarters of metanepisternum. Interstrial setae truncated, as broad as long, strial setae coarse.
Description male. Length 1.0-1.1 mm, 2.0× as long as wide. Colour black. Head. Frons convex, strongly reticulate, slightly impressed and shiny on median third just above epistoma; vestiture consisting of fi ne hair-like setae and fewer spatulate setae directed inwards, a dense brush on epistoma. Scapus long; funiculus 3-segmented, pedicel longer than segments 2-3 combined; club with two transverse sutures marked by setae and small grooves. Pronotum strongly reticulate, granulated and sharply asperate on median third of anterior three-quarters, two small asperities near anterior margin; vestiture of mixed recumbent fi ne setae and erect scale-like setae, some fi ne bifi d setae near lateral margin. Scutellum not visible. Elytral base with raised crest consisting of fi ve equally long teeth on each elytron, the inner two on each elytron fused; striae weakly impressed, punctures deep, in regular rows, separated within rows by half their diameter; interstriae and space between strial punctures rugose. Vestiture consisting of erect, truncated interstrial setae, and coarse recumbent strial setae spaced their length apart. Legs. Protibiae laterally with 2 tiny teeth, inner mucro long and curved posterolaterally. Meso-and metatibiae with 4 lateral socketed teeth on apical third.
Female. Identical to male.

Distribution. Known from the Eastern Cape and North Cape provinces of South Africa.
Remarks. Breeds in dead parts of large succulent Euphorbia. Differs from the very similar A. euphorbiae by the short and broad truncated interstrial setae, which are more densely spaced, and by the thicker strial setae. There are also slight differences between the two species in the shape and distribution of the coarse and fi ne setae on the pronotum. Diagnosis. Antennal scapus with a long tuft of setae on distal third; funiculus 3-segmented; club strongly elongated, pubescent, with two procurved sutures barely visible. Pronotum with some bifi d setae intermixed near lateral margin. Elytral base with crenulation reaching interstriae 6, with fi rst two teeth on each elytron fused, additional 4-5 teeth free; elytral interstriae 2 with sharp spines, which are slightly longer than elytral setae.

Remarks.
Even though this characteristic species differs markedly in several features from Styracoptinus, it is not unlikely that they are congeneric given the modest genetic differences observed in many genes (Pistone et al., 2018).

Diagnosis.
Antennal scapus with a long tuft of setae on distal third; funiculus 3-segmented; club with two strongly procurved sutures marked by setae. Pronotum with some bifi d setae intermixed laterally along the hypomeron. Elytral base with fi rst two teeth on each elytron fused and an additional three teeth; elytral disk and declivity with spines and tubercles.
Remarks. Molecular data, morphological features of male genitalia and external characters such as a contiguous row of plumose setae on most of the metanepisternum, short entire eyes, and the shape of the protibiae, support a close relationship with Hypoborina and thereby inclusion in Hypoborini. The phylogenetic position as sister to Hypoborina, the lack of raised teeth along the elytral base, and, although not exclusively, the open anterior plate on the proventriculus, support a separate status as a subtribe in the Hypoborini.

Diagnosis.
Eye entire, short, oval. Antennal club smooth and shiny, with lateral tufts of setae. Funiculus 3-5 segmented. Pronotum dome-shaped, occasionally humpbacked, with large, rounded tubercles on anterior three-quarters or more, rarely with smaller sharp asperities; posterior margin of pronotum rounded, vestiture of mixed scale-and hairlike setae. Scutellum not visible. Elytral base has a fi ne rim. Interstrial setae erect, spatulate, in single rows; strial setae recumbent, short and hair-like. Setae on metanepisternum plumose or bifi d, in row parallel to sclerolepidiae and continue as plumose scales on metepimeron and near anterior margin of metacoxae. Procoxae contiguous; mesocoxae widely separated.

Etymology.
Greek, composed of the stem of the noun Xerasia, meaning dryness or drought, and the noun borus, meaning excessive feast, referring to the preferred development in dry wood in arid warm habitats. Gender masculine.

Distribution. Madagascar, Tanzania.
Key to species Diagnosis. Asperities on pronotum very large, four tubercles form an irregular transverse row along anterior margin; setae on metanepisternum bifi d, near metacoxae plumose.
Description, male. Length 0.8-0.9 mm, 2.1-2.2× as long as wide. Colour dark brown. Head. Frons granulated on upper half and vertex, lower median half and epistoma smooth and shiny, impunctate; vestiture consisting of scattered, short, fi ne setae. Funiculus 3-segmented, pedicel much longer than segments 2-3 combined; club shiny, without sutures, slightly indented laterally with tufts of short setae. Eyes separated above by 2.8-3.2× their width. Pronotum dome-shaped, with huge, rounded asperities or tubercles present from near posterior margin to anterior margin, which has a transverse row of four tubercles. Vestiture of mixed hair-like and short spatulate setae. Elytral base has a fi ne rim, scutellum barely visible. Striae not impressed, punctures deep, in rows, separated on average by 2× their diameter; interstriae shiny, fi nely granulated; vestiture consisting of rows of short, slightly curved scalelike setae, and very fi ne, minute, recumbent strial setae. Ventral sclerites. Setae on metanepisternum in row along the sclerolepidia, plumose at anterior and posterior ends, bifi d along most of its middle part. Legs. Protibiae with two small, socketed teeth along the lateral edge. Metatibiae with three socketed teeth on apical fourth.
Female. Identical to male.

Distribution.
Madagascar. Only known from the type locality in the southern lowlands on the island.

Remarks.
Can be distinguished from the closely related X. bituberculatus sp. n. (described below) by the four tubercles on the anterior margin of the pronotum, the continuous distribution of other asperities, the more broadly separated eyes and its slightly larger body size. Both species were found in sifted litter of dry shrub vegetation, in two nearby localities together with an equally tiny species of Microlanurgus Jordal, 2021.
Description, male? Length 0.7 mm, 2.1× as long as wide. Colour black. Head. Strongly reticulated, tiny longitudinal impression on median half; vestiture consisting of scant, short, fi ne setae. Funiculus 3-segmented, pedicel much longer than segments 2-3 combined; club shiny, without sutures, laterally lightly indented with tufts of short setae. Eyes separated above by 2.3× their width. Pronotum dome- shaped, strongly reticulated, with big, rounded asperities present from near posterior margin to anterior fi fth, then a smooth gap to the anterior margin, on which there are two enlarged tubercles. Vestiture consisting of scant hair-like and bristle-like setae. Elytral base has a fi ne rim, scutellum minute, barely visible. Striae not impressed, punctures in rows, deep, large, on average separated by their diameter; interstriae fi nely rugose, shiny; vestiture consisting of uniseriate interstrial rows of short, curved spatulate setae increasing in size posteriorly, spaced at 3-5× their length, and very fi ne minute, semirecumbent strial setae. Ventral sclerites. Setae on metanepisternum largely abraded or reduced, a few plumose setae just anterior to the metacoxae. Legs. Protibiae with two small, socketed teeth along the lateral edge. Metatibiae with three socketed teeth laterally on apical fourth. Type material. Holotype, male?: Madagascar, Mahafaly Plateau, 6.2 km 74 deg ENE Itampolo [-24.627, 44.077], in sifted litter, BLF5758, B. Fischer, leg. Holotype deposited in CAS.
Etymology. Composed of the Latin prefi x bi-, meaning two (parts), and tuberculatus (see above), referring to the two large tubercles on the anterior margin of the pronotum.

Distribution.
Madagascar. Only known from the type locality in the southern lowlands on the island.
Description, male. Length 0.9-1.1 mm, 2.2-2.5× as long as wide. Colour brown to dark brown. Head. Frons convex, surface reticulated; vestiture consisting of fi ne short setae, which are more densely spaced on epistoma. Funiculus 4-segmented, pedicel as long as segments 2-4 combined; club shiny, without sutures, lightly indented laterally with tufts of short setae. Eyes separated above by 1.7-1.9× their width. Pronotum dome-shaped, anterior three-quarters shiny with large sharp asperities, anterior margin with row of four large asperities. Vestiture consisting of mixed hair-like and scale-like setae. Elytral base has a sharp rim, scutellum barely visible. Striae weakly impressed, punctures small, lightly impressed, in rows, on average separated by 1-1.5× their diameter; interstriae shiny, fi nely and increasingly granulated posteriorly; vestiture consisting of rows of short, erect, truncated scale-like setae and very fi ne, minute, recumbent strial setae. Ventral sclerites. Setae on metanepisternum broadly plumose, densely spaced in a row; setae elsewhere mixed but mainly trifi d. Legs. Protibiae with three small, socketed teeth along the lateral edge. Metatibiae laterally with four socketed teeth on apical third.
Female. Identical to male.
Type locality. Tanzania, Morogoro province, Sanje. Etymology. Named after the Zambesian biogeographical region, with the Latin suffi x -anus to create a masculine nominative adjective, meaning origin in, or possession of, Zambesi.

Distribution. Tanzania, Udzungwa Mountains.
Remarks. Although this is the only species in this genus known from the African mainland, and the molecular data place it as a sister to the two included species from Madagascar, it is a typical Xerasiborus within the acceptable genetic and morphological variation for this genus. Diagnosis. Asperities on pronotum not larger than the antennal pedicel, anterior margin with two small asperities; setae on metanepisternum large, plumose; pronotal and interstrial setae mainly spatulate.
Description, female. Length 1.2-1.3 mm, 2.3-2.5× as long as wide. Colour dark brown to black, legs slightly lighter. Head. Frons convex above, increasingly impressed and shiny from upper level of eyes to epistoma, granuloreticulate elsewhere, with a tiny smooth callus just above epistoma; vestiture consisting of fi ne short setae, which are more densely spaced on epistoma. Funiculus 4-segmented, segments 2-4 combined slightly longer than pedicel; club shiny, without sutures, lightly indented laterally with tufts of short setae. Eyes separated above by 3.2-3.5× their width. Pronotum humpbacked, summit just behind middle, surface sub shiny, reticulated, anterior margin with two small asperities, on anterior three-quarters with densely spaced coarse asperities, fi nely granulo-punctate elsewhere. Vestiture consisting of mixed hair-like and spatulate scale-like setae. Elytral base has a sharp rim, scutellum barely visible. Striae not impressed, punctures very small, in rows, separated by 3-5× their diameter; interstriae shiny, granulated; vestiture consisting of rows of curved, spatulate setae, spaced apart by a distance equal to their length, slightly longer and more densely spaced on the declivity, and very fi ne, minute, recumbent strial setae. Ventral sclerites. Setae on metanepisternum broadly plumose, densely spaced in mainly a single row; setae elsewhere mixed, mainly plumose and trifi d, some bifi d. Legs. Protibiae with three small, socketed teeth along the lateral edge. Metatibiae with four socketed teeth on apical third.
Male. Similar to female except lower frons more strongly impressed and mandibles are distinctly prognathous.

Distribution. Madagascar.
Remarks. Only known from the type locality at Ankarana, Madagascar. This species breeds in recently dead branches of Euphorbia tirucalli in sun exposed, hot places. Egg galleries were rather irregular and confl uent. When suitable, most parts of a dead branch were eaten and the species is therefore likely to be abundant where the host plant occurs. This is the only species in this genus in which the frons is distinctly sexually dimorphic.
Description, male. Length 1.1-1.3 mm, 2.2-2.3× as long as wide. Colour brown. Head. Frons convex above, fl at on lower half, fi nely reticulate, dull; vestiture consisting of fi ne short setae except for a few coarse intermixed setae, on epistoma more densely spaced. Funiculus 5-segmented, segments 2-5 combined longer than pedicel; club shiny, without sutures, lightly indented laterally with tufts of short setae. Eyes separated above by 2.1-2.3× their width. Pronotum dome-shaped, summit just behind middle, surface granulo-punctate, anterior margin with row of four small asperities, on anterior three-quarters densely spaced, square, sharp asperities. Vestiture consisting of mixed hairlike and spatulate setae. Elytral base a thin irregular rim, scutellum barely visible. Striae not impressed, punctures small, deep, in irregular rows, separated by their diameter; interstriae shiny, fi nely rugose; vestiture consisting of rows of erect, spatulate setae, each separated by slightly less than their length, and very fi ne, recumbent strial setae, each slightly longer than distance between setae. Ventral sclerites. Setae on metanepisternum broadly plumose, mainly in a single row; setae elsewhere mixed plumose, trifi d and bifi d. Legs. Protibiae with three small, socketed teeth along the lateral edge. Metatibiae with four socketed teeth on apical third.
Female. Not identifi ed, presumably identical to male in external characters. Distribution. Madagascar (see Fig. 47).

Remarks.
Only known from the type locality near Montagne d'Ambre, Madagascar where it was sifted from leaf litter.

Genus Nisiborus gen. n.
ZooBank taxon LSID: 8FCAB21A-74BB-46FA-831C-F8B2E09DEE2B Type species. Ptilopodius hylesiniformis Schedl, 1961. Diagnosis. Eyes entire, short, oval. Scapus elongated, much longer than funiculus; funiculus 4-segmented; club fl attened, smooth and glabrous, lateral margins somewhat irregular, terminally with a suture that is only visible when viewed from above or behind. Pronotum fi nely asperate, posterior margin rounded, vestiture consisting of mixed hair-like or mixed scale-and hair-like setae. Scutellum very small, barely visible. Elytral base with a low irregular rim; interstrial setae scale-or hair-like, in single rows, strial setae fi ne to coarse, recumbent, variably in rows or confused. Procoxae contiguous; metacoxae broadly separated. Protibiae narrow, with 3 socketed teeth on the lateral margin, the inner mucro rather long, curved posterolaterally; meso-and metatibiae narrow, with 4 socketed teeth laterally on apical one-third. Setae on metanepisternum characteristically scale-like or plumose, running in a parallel line to the sclerolepidia, posteriorly turning dorsally on the epimeron and usually also ventrally just anterior to the metacoxa. Hindwings with 5 setae in cluster on subcosta, pterostigma (radial cell) with two setae. Proventriculus with apical plate much longer than posterior plate, median suture open, with tubercles along its inner margin; apical teeth absent, closing teeth short and simple. Aedeagus dorsoventrally curved, apophyses as long as aedeagal body; tegmen a closed ring, manubrium long, curved; spiculum gastrale a simple rod.

Etymology.
Greek, composed of the noun nisi, meaning island, and the noun borus, meaning glutton or extravagant feast, or in a wider context also used for excavating wood, referring to the endemic distribution on Madagascar, apparently thriving in small pieces of woody plant tissue. Gender masculine. (Schedl, 1961), Nisiborus schaufussi sp. n.  48,51,49,52,50,53, Distribution. Madagascar. Remarks. The type species was originally placed in Cryphyophthorus Schedl. However, the type species of Cryphyophthorus differs from Nisiborus in having sinuate eyes, sharp rim along the posterior margin of the pronotum, pronotal surface not strongly asperate, scutellum moderately large and visible and fl ush with the elytra, protibiae broad apically with two large socketed teeth, and striae lack minute setae. These differences require a new genus for Cryphyophthorus hylesiniformis (Schedl, 1961) and one undescribed species. They are closely related to Xerasiborus, but distinguished from that genus mainly by the broader distribution of much smaller asperities on the pronotum, and the longer and more evenly distributed sparse setae along the lateral margin of the antennal club. Diagnosis. Antennal club shiny, nearly glabrous; pronotum with fi ne asperities and hair-like setae; setae on elytral striae very fi ne, hair-like, in regular rows.
Female. Externally identical to male. Remarks. This is the fi rst host record for this species, which was dissected from a thin branch of a fi g tree.

Figs 49, 52, 55
ZooBank taxon LSID: AFB4D4B9-F7AB-4A80-8E82-3DF7F17E30A1 Diagnosis. Antennal club shiny, nearly glabrous, pronotum with fi ne asperities. Distinguished from N. hylesiniformis by the coarse and sub-plumose strial setae which are more densely placed and in part confused, by the intermixed scale-like setae on pronotum and the more broadly distributed plumose scales on the anterior part of the metaventrite.
Description, male. Length 1.2 mm, 2.3× as long as wide. Colour dark brown to black, setae yellowish white. Frons convex above, on central third just above epistoma a smooth and shiny groove; eye entire, separated above by 2.0× their width; scapus elongated; funiculus 4-segmented, segments 2-4 as long as the pedicel; club smooth and shiny, with 3-4 long, thin setae and many long lateral setae, posterior face with two irregular sutures near apex. Pronotum gently rounded, fi nely asperate, coarsely reticulated and granulated; basal margin rounded, lateral margins abrupt but not sharp; vestiture of mixed hair-like and scalelike setae. Scutellum not visible. Elytral base fi nely carinate, elytral apex very narrowly rounded; striae lightly impressed, punctures small; interstriae rugose and granulated, broader than striae; vestiture consisting of erect scale-like interstrial setae, and densely spaced recumbent sub-plumose strial and interstrial setae. Legs. Procoxae contiguous, mesocoxae broadly separated. Protibiae marked on its inner margin by a broad indentation associated with dense, rigid setae further above; lateral margin with 3 small socketed teeth, the inner mucro long, curved posterio-laterally; metatibiae with 4 thin lateral teeth on apical third. Ventral sclerites. Mesanepisternum with row of broad plumose setae parallel and contiguous with sclerolepidia.
Female. Not known, presumably similar to the male in external characters. Diagnosis. Length 1.5 mm, 1.3× as long as wide. Frons (sex?) strongly concave, antennal funiculus 5-segmented, segment 2 longer than pedicel; club fl attened, as wide as long, with two broadly procurved sutures marked by setae; eyes entire, very elongated. Pronotum large, almost as long as elytra, wider than long; vestiture consisting of pale scales. Scutellum not visible. Elytral base with fi ne crest, elytra variegated, with interstrial setae short, scale-like and confused, and minute strial setae. Protibiae narrow, with four small, lateral teeth, inner mucro large, curved posterio-laterally.
Included species: Glochiphorus globosus Strohmeyer, 1910, Glochiphorus alienus Schedl, 1982. Distribution. Madagascar, South Africa? Remarks. The protibiae, eyes and basal rim of the elytra suggest placement in Hypoborini, more specifi cally Xerasiborina, but this must be regarded as highly tentative. Six missing characters in the morphological character matrix further reduces confi dence in the deviant position in the morphological phylogeny (Fig. 2). The genus is distinguished from all hypoborines by the long segment 2 of the antennal funiculus and large fl at club with broadly procurved sutures marked by setae. The diagnosis is based only on the type species. The second species included, G. alienus, has deviant features such as crenulations reaching the humeral angle and will possibly be removed when more specimens become available in the future. Diagnosis. Antennal funiculus 5-segmented, last segment extended laterally; club shiny, nearly glabrous. Pronotum with fi ne asperities mainly on central two-thirds of anterior half. Scutellum not visible. Elytral base crenulated between interstriae 1-5; elytral vestiture consisting of erect interstrial bristle-like setae and short, fi ne strial setae. Setae on metanepisternum plumose, in a row parallel to the metepisternal suture.
Distribution. Palau. It is likely there are several undescribed species, all from SE Asia (A. Johnson, pers. comm.).
Remarks. Resurrected from the genus Liparthrum. Distinguished from Liparthrum, Corditarsus and Hypoborus by the more evenly distributed small asperities on the pronotum and shiny antennal club without sutures, and from Liparthrum and Hypoborus by the broader median suture on the proventriculus, and from Liparthrum by the 5-segmented antennal funiculus.
Remarks. The only similarity to Hypoborini is the elevated crest at the elytral base, but this character differs as the inner two teeth are much bigger than the other teeth. The body plan differs fundamentally as the postnotum is fused and the anterior plate of the proventriculus lacks a median suture. It has therefore been suggested on several occasions that this genus is unrelated to other Hypoborini (Nobuchi, 1969;Wood, 1986;Israelson, 1990). Molecular data has furthermore conclusively excluded Chaetophloeus from the Hypoborini (Jordal & Cognato, 2012; and the genus should therefore be placed in a separate tribe. Schedl, 1953 Figs 50, 53, 56 Type species. Cryphyophthorus eggersi Schedl, 1953 (original designation).
Remarks. The type species of this genus has several features not compatible with Hypoborini, including a sharp rim on the posterior margin of the pronotum, sinuate eyes and no strial setae on the elytra. According to the description (not visible on the pinned holotype), the protibiae widen towards apex. Furthermore, the pronotum is not asperate. In conclusion, this species is not congeneric with Nisiborus hylesiniformis or other hypoborine taxa. More material is needed to assess tribe membership, but it may belong to Trypophloeini or Ernoporini.