Dtsch. Entomol. Z. 71 (1) 2024, 67-84 | DOI 10.3897/dez.71.116185 Gp tusruM ror BERLIN Integrated taxonomy, biology and biogeography of the Afrotropical genus Xyloctonus (Coleoptera, Curculionidae, Scolytinae) Bjarte H. Jordal? 1 Department of Natural History, University Museum of Bergen, University of Bergen, P.O. 7800, NO-5020 Bergen, Norway https://zoobank. org/E85 152C0-2B48-4B 15-A49F-776D7CD4CBA4 Corresponding author: Bjarte H. Jordal (bjarte.jordal@uib.no) Academic editor: Harald Letsch # Received 23 November 2023 @ Accepted 8 February 2024 @ Published | March 2024 Abstract The peculiar Afrotropical bark beetle genus Xv/octonus Eichhoff, 1872 is revised and its biology described. Several unusual morpho- logical features reflect adaptations to predator avoidance as they are highly exposed during mating externally on tree trunks and branch- es. Observations invariably indicate that males and females abandon the nest under bark at an early stage of progeny, the males already before eggs hatch, potentially engaging in subsequent additional matings. Most species have a clear preference for host plants in the plant family Sapotaceae. Although the genus 1s broadly distributed in forested parts of Africa, Madagascar and Mauritius, most species are found in the eastern part of this range. A Bayesian biogeographical analysis revealed a possible origin of the genus in Madagascar in the early Eocene, with subsequent colonisation of the southern African region in late Eocene. This contrasts with the closely-related xyloctonine genus Cfonoxylon Hagedorn, 1910, which is of western Congolian ancestry and more recently reached Madagascar mul- tiple times during late Miocene. Two new species are described: Xyloctonus magnus sp. nov. from Madagascar and_X. genieri sp. nov. from Burkina Faso. Synonyms are proposed for X. swhcostatus Eggers, 1939 (=X. striatus Eggers, 1939) and _X. scolytoides Eichhoff, 1872 (=X. latus Eggers, 1922). Identification to species is provided in a key illustrated with photographs of most species. Key Words bark beetles, Bayesian Binary MCMC, phylogeny, Reconstruct Ancestral State in Phylogenies, taxonomy Introduction Xyloctonini are a characteristic group of tropical bark beetles in the weevil subfamily Scolytinae. It includes five genera: Glostatus Schedl, 1939, Cryphalomimus Eggers, 1927, Ctonoxylon Hagedorn, 1910 and Xyloctonus Eich- hoff, 1872 are all Afrotropical, whereas Scolytomimus Blandford, 1895 is restricted to the Indo-Malayan and Australian Regions. A recent revision of Glostatus placed this genus in a separate subtribe Glostatina Jordal, 2023 and also revealed a rather chaotic taxonomy for this group of beetles. Ctonoxylon and Xyloctonus are, on the other hand, taxonomically stable groups at the generic level and their morphology leaves little doubt about their affinity (Jordal 2023). The peculiar look of Xv/octonus (Figs 1, 2) and the other genera in subtribe Xyloctonina is most strik- ingly expressed in the rounded and inflated shape of the pronotum, a deep groove on the anterior side of the pro- tibiae and the impressed lateral sclerites of the metatho- rax for reception of femur and tibiae (Menier 1974). Such highly-specialised features led some authors to place these weird beetles in their own subfamily Xyloctoninae (Hopkins 1915; Sched! 1961b) or family Xyloctonidae (Eichhoff 1878). Observations on their biology are few and anecdotal, but all species are true bark beetles with likely narrow host plant preferences (Sched! 1961b). Both Ctonoxylon and Xyloctonus are broadly Afro- tropical. However, Xyloctonus has one-third of the spe- cies endemic to Madagascar, whereas Ctonoxylon until recently did not have any species verified from this island (Wood and Bright 1992). The predominantly Congolian affinities of Ctonoxylon may explain its scarce presence on Madagascar, whereas the largely Zambesian distribu- tion of African Xyloctonus could have facilitated a closer Copyright Bjarte H. Jordal. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 68 connection with this island. A biogeographical analysis of Xyloctonini and outgroups is, therefore, presented to test these hypotheses, using reconstruction of ancestral areas in a Bayesian framework. Rather few publications have dealt with the taxon- omy of Xy/octonus (see Eggers (1939); Sched! (1953); Menier (1974)) and, generally, very little is known about morphological variation, behaviour and geographical distribution. The taxonomy and biology are, therefore, revised, including an identification key and photograph- ic illustrations. Two new species are described and two other species synonymised which leaves the total number of species at 15 (Table 1). Recent fieldwork has provided new host and country records which, together with ob- servations on their behaviour, will contribute to a better understanding of distribution and ecology. Table 1. Currently valid species of the genus Xv/octonus E1ch- hoff, 1872 and their known distribution. Xyloctonus aethiops Schedl, 1953 Xyloctonus bimarginatus Eggers, 1939 Democratic Republic of the Congo Madagascar Xyloctonus biseriatus Schedl, 1953 Xyloctonus genieri Jordal, sp. nov. Madagascar Burkina Faso Xyloctonus maculatus Schedl, 1965 — South Africa Xyloctonus magnus Jordal, sp. nov. Madagascar Xyloctonus mauritianus Menier, 1974 Mauritius Xyloctonus niger Schedl, 1938 Uganda Xyloctonus opacus Schedl, 1957 Rwuanda Xyloctonus pubifer Schedl, 1965 Zambia, South Africa Xyloctonus punctipennis Eggers, 1939 Somalia Xyloctonus quadricinctus Schedl, 1941 Ghana, Tanzania Xyloctonus quadridens Schedl, 1953 Madagascar Xyloctonus scolytoides Eichhoff, 1872 Tropical Africa, incl. South Africa Guinea, Burkina Faso, Democratic Republic of the Congo, Sudan, Tanzania, Mozambique Xyloctonus subcostatus Eggers, 1939 Material and methods Eggers (1939) often used the informal term type and co- type. The purpose of these terms was clearly holotype (see Wood and Bright (1992)) and paratype. Specimens stud- ied are deposited in the following museum collections: CAS California Academy of Sciences, San Fran- cisco, USA. CMNC Canadian Museum for Nature, Ottawa, Can- ada (Genier coll). RBINS Royal Belgian Institute of Natural Sciences, Brussels, Belgium. RMCA Musee Royal de I‘Afrique Centrale, Tervu- ren, Belgium. MNHN Museum National d’Histoire et Naturelle, Paris, France. MZH Finnish Museum of Natural History, Helsin- ki, Finland. dez.pensoft.net Bjarte H. Jordal: Taxonomic revision of Xy/octonus NHMUK The Natural History Museum, London, UK. NHMW __Naturhistorisches Museum, Vienna, Austria. USNM National Muséum of Natural History, Wash- ington D.C., USA. UWCP Museum of Natural History, University of Wroclaw (Wanat coll). ZMHB Museum fiir Naturkunde der Humboldt-Uni- versitat, Berlin, Germany. ZMUB University Museum of Bergen, Norway. Specimens collected by the author were dissected from recently dead wood and lianas identified by local plant experts. Careful removal of bark allows for reconstruc- tion of family structures and brood size. It was noted if a nuptial chamber was present inside the entrance and whether the direction of the egg tunnel (gallery) was parallel or transverse to the wood grain as this is often a species specific trait. The stage of development (larvae, pupae, teneral adults) was noted for each observation and if one or both parents were still present. External morphological characters were studied in a Leica MZ16 and photographs made with Leica LAS software on a Leica M205 C stereomicroscope. Internal morphological characters were dissected and reported in a previous paper (Jordal 2023). Biogeographical analyses were based on a new time-calibrated phylogenetic tree as the basis for recon- structing ancestral areas. The molecular data used to re- construct the time tree were mitochondrial COI and nu- clear 28S and EF-1qa, as described in a recent publication (Jordal 2023). Approximate clade ages were estimated in Beast 1.10.4 (Drummond and Rambaut 2007), with the xml file prepared in Beauti. Rates were calibrated with time estimates from a previous analysis of Scolytinae, based on 18 genes (Pistone et al. 2018) and given a normal distribution with five standard deviations to accommo- date for uncertainties in these estimates. Nodes used for calibration included the root which combined taxa from Tpini, Hypoborini and Micracidini at 88 Ma, Micracid- ini without Leiomicracis at 79 Ma and the Neotropical micracidine clade at 65 Ma. These particular nodes had relatively small differences between stem and crown ages and estimates were robust across different studies (Jordal and Cognato 2012; Pistone et al. 2018; Jordal 2021a, b). Published estimates on the Xyloctonini lineages were ex- cluded to avoid potential bias in the new estimate using a much larger ingroup sample. Ancestral areas were reconstructed in RASP (Yu et al. 2020) using 1 million iterations of the Bayesian Binary MCMC (BBM) method, based on the new time-tree re- constructed in Beast. The preferred model F81 allows different frequencies of areas in the dataset which better accommodate the small samples of species from Mada- gascar and southern Africa compared to the Congolian and Zambesian regions. Due to the highly-restricted dis- tribution of most species of Xyloctonini, the maximum number of occupied areas was set to 2. Areas were gener- ally defined as the biogeographic regions (realms) of the Dtsch. Entomol. Z. 71 (1) 2024, 67-84 world, with the target area Afrotropics (Ethiopian region) divided further into statistically-defined regions sensu Linder et al. (2012): Madagascar, Congolian (= Shaba, Congolian and Guinean clusters), Zambesian and south- ern African (= Namib, Kalahari, Cape and Natal clusters) regions, which are the only relevant areas for the Xyloc- tonini taxa treated here. Results Phylogenetics and Afrotropical biogeography of Xyloctonini The recent phylogenetic study of Xyloctonini resulted in a monophyletic group of five Xv/octonus species which were maximally supported as sister to Scolytomimus Blandford 1895 (fig. 1 in Jordal (2023)). The distinctness of Xyloctonus is also supported morphologically (fig. 2 in 69 Jordal (2023)), in particular by the symmetrically rounded and flat antennal club with two or three procurved sutures and the genus connects with Scolytomimus by the steeply rising venter meeting a short elytral declivity (Figs 1, 2). These two genera share with Cryphalomimus a carinated shape of the elytral interstriae (Figs 1-5) and, together with Ctonoxylon, all four genera have deeply-grooved protibiae for reception of the tarsi and a large and scoop- like manubrium of the aedeagal tegmen (Jordal 2023). A new Beast analysis of the molecular data showed similar relationships between genera (Fig. 6), with Glostatus separated from the other four genera. With- in Xyloctonus the two South African taxa X. maculatus and X. /atus were nested within the Malagasy clade, as opposed to the previously published MrBayes analysis (fig. 1 in Jordal (2023)). Reconstructions of possible ancestral areas revealed contrasting patterns for the three xyloctonine genera with multiple species sampled (Fig. 6). On the basis of os: > ae Figures 1—5. Posterior view of elytral declivity in 1. Xyloctonus quadridens; 2. X. maculatus; 3. X. subcostatus (paratype of X. striatus), 4. X. pubifer, 5. X. scolytoides (paralectotype of X. /atus). Black arrows points at the shallow furrow on the posterior side of the metatibiae, similar to mesotibiae. White arrow points to the impression of the metaventrite which receives the metafemur. Yellow arrows point at elytral interstriae 9, which in Figs 1-4 runs to the elytral sutures and blocks interstriae 1-8 from reaching elytral apex; in_X. scolytoides (Fig. 5) all interstriae reach the posterior margin of the elytra. dez.pensoft.net 70 Bjarte H. Jordal: Taxonomic revision of Xyloctonus Ips acuminatus Orthotomicus proximus © Cactopinus rhettbutleri ©@ Hylocurus femineus Lanurgus mattheei Ernoporus tiliae ° Eidophelus spessivtzevi © Procryphalus mucronatus Dacryostactus kolbei Corditarsus australis Cryphalus longus e PN Trypodendron domesticum S © Xyloterinus politus Cryphalomimus striatus Scolytomimus philippinensis 3, Xyloctonus maculatus | oN Xyloctonus pubifer Xyloctonus aethiops Xyloctonus quadridens Xyloctonus biseriatus ee , © Ctonoxylon flavescens Ctonoxylon sp. 11 @ Ctonoxylon sp. 04 Kor) Total Ctonoxylon uniseriatum © Ctonoxylon setifer Ctonoxylon amanicum ( ©) ‘ © Ctonoxylon sp. 05 (CP = Ctonoxylon sp. 06 ‘Tl ©, © Ctonoxylon atrum Ctonoxylon methneri 4 © Trypophloeus populi @ Trypophloeus granulatus Afrocosmoderes madagascariensis by) Hypothenemus sp. nr. eruditus A - Palearctic Hypothenemus birmanus Glostatus giganteus B - Neotropical CE) © Glostatus pondoanus C - Congolian Glostatus tuberculatus (=) (<) ) Glostatus mkulumusius D - Zambesian (p) © Glostatus scutiae (S) E - Southern African Glostatus sp. | z F - Madagascar © Glostatus tenuis © Glostatus leprosus G - Nearctic © © Glostatus paraxyloctonus H - Australasian/Indomalayan Glostatus aculeus Glostatus procurvus 100 80 60 40 20 myr Figure 6. Reconstruction of ancestral geographic areas in RASP using the BBM method on a Beast estimated time-tree. The most likely ancestral area is noted by a letter in centre of each pie diagram, with alternative states coloured according to their likelihood proportions. The map inserted shows the approximate extent of relevant Afrotropical subregions sensu Linder et al. (2012). dez.pensoft.net Dtsch. Entomol. Z. 71 (1) 2024, 67-84 this dataset, Xy/octonus was inferred to have originated in Madagascar 52-45 Ma. The southern region of Af- rica was thereafter reached from Madagascar no later than 31 Ma. Cronoxylon indicated a Congolian ances- try some 64-47 Ma, with more recent expansions to the Zambesian and southern African regions. Colonisation of Madagascar occurred twice and no earlier than 13 and 16 Ma, possibly much later, as these were single species with rather similar morphology to their continental sis- ter species (Jordal, in prep.). G/ostatus is not part of the core Xyloctonini and is not found on Madagascar (Jordal 2023); its inferred ancestry in the Zambesian region was strongly supported and occurred some 82-68 Ma, with a more recent expansion to the southern parts of Africa not earlier than 35 Ma. Taxonomy Xyloctonus Eichhoff, 1872 Type species. Xyloctonus scolytoides Eichhoff, 1872 (by monotypy). Diagnosis. Eyes divided, except broadly emargin- ated in XY. maculatus and X. genieri sp. nov. Antennal scapus longer than the 6-segmented funiculus; club flat, outline round, with three, or more rarely two, strong- ly procurved sutures marked by dense white or golden setae (Figs 22, 40). Pronotum spherical in both lateral and frontal view, lateral margins carinate; anterior half asperate, with either two or four raised teeth along an- terior margin. Scutellar shield (scutellum) slightly de- tached from elytra; interstriae carinate (only declivity in X. aethiops), interstrial carinae either reaching posterior margin or more often disrupted by a curved interstriae 9 that reaches elytral suture near apex; declivity short and gently sloping (steep and longer in_X. maculatus). Metanepisternum, metaventrite and first ventrite usual- ly with split setae, trifid or occasionally plumose setae often present near mesoventrite. Ventrites 3—5 usually steeply rising to meet elytra. Procoxae contiguous; pro- tibiae with deep furrow of anterior face to receive tar- $1; other tibiae with distinct, but shallower furrow on its posterior face. Proventriculus with posterior plate strongly reduced, anterior plate with partially open and indistinct median suture, plate covered by simple obtuse tubercles. Male genitalia with large complex intromittent organ (basal sclerites), apophyses (penis apodemes) as long as penis body; tegmen open dorsally, ventrally with a large scoop-shaped manubrium; spiculum gastrale as simple thin curved rod. Differential diagnosis. This genus differs from Scoly- tomimus by the distinct procurved sutures in the antennal club and by the irregular impression around the scutellar shield. It is further distinguished from Cryphalomimus and Ctonoxylon by the 6-segmented antennal funicle, a rather short, oblique elytral declivity and the symmetri- cally procurved sutures in the antennal club. 71 The emarginatus group Two species are included in this group, defined by hav- ing all interstriae reaching the apical margin of the elytra (Fig. 5). One of the taxon names used in the past was ‘emarginatus’, now a synonym of scolytoides, describing this condition (see bimarginatus group below). Xyloctonus scolytoides Eichhoff, 1872 Figs 7, 8, 10, 11, 13, 14 Xyloctonus scolytoides Eichhoff 1872: 134. Xyloctonus emarginatus Eggers, 1939: 16, synonymy by Menier, 1974. Xyloctonus latus Eggers, 1939: 14, syn. nov. Type material. Syntypes of X. scolytoides: [South Afri- ca] Port Natal [-29.87, 30.97], Dej. [RBINS]. Paratype of X. emarginatus: [Democratic Republic of the] Congo, Ituri, Dyugu, 13. VII.1931, leg. J. Lebrune [RMCA]. Lec- totype of X. /atus: [Ethiopia] Abyssinia, 8000 feet alt. IX—X 1926, Dr. H. Scott [NHMUK]; and paralectotype, same data [NHMW]. Diagnosis. Length 2.1—2.6 mm, 1.9-2.1 as long as wide, colour light to very dark brown; antennal club with two visible procurved sutures; frons with fine setae; ante- rior margin of pronotum with two raised teeth (Figs 7, 10); all elytral interstriae carinate, reaching posterior elytral margin; strial and interstrial punctures moderately deep; scutellar shield impressed in middle, appearing bilobed; elytral suture with bulgy locking mechanism behind scutellar shield; setae on lateral metaventrite mainly bifid or trifid, anteriorly more plumose. Distribution. Burkina Faso (new country record), Ghana, Ivory Coast, Nigeria, Cameroon, Democratic Re- public of the Congo, Uganda, Sudan, Ethiopia, Tanzania, Zambia, South Africa. New records. Burkina Faso, Bale, Boromo [11.755, -2.929], 250 m alt. F. Genter, leg., 10.8.2006, light trap; Comoe, Foret de Boulon [10.343, -4.510], 270 m alt., F. Genier leg., 9.7.2006, flight intercept trap, light trap and Malaise trap; Kompienga, 15 km E Nadiagou [11.113, 0.909], 155 m alt., F Genter leg., 25.8.2005, flight in- tercept trap, light trap and Malaise trap; Loroum, Toulfe [ 13.873, -1.950], 300 m alt., F. Genier leg., 16.7.2006, light trap; Nahouri, Foret de Nazinga [11.045, -1.420], 310 m alt., F. Genier leg., 27.7.2006, light trap and Malaise trap; Passore, 8 km SE Yako [12.928, -2.216], 320 m alt., F. Ge- nier leg., 7. 8. 2006, light trap; Sanguie, Foret de Sorobou- li [11.893, -2.799], 270 m alt., F. Genter leg., 13.7.2005 and 28.7.2006, light trap; Ouagadougou, 03.11.1973, R. Linnavouri [MZH]; Bobo Dioulasso, 03.11.1973, R. Lin- navour! [MZH]; Nigeria, Kano-Wudil, 17.05.1973, R. Lin- navouri [MZH]; Serti [7.51, 11.36], 29. March 1970, coll. J.T. Medler; Cameroon, 35 km S Garoua [9.01, 13.34], 30 March 1972, at black light, JA Gruwell; Tanzania, W. Us- ambara, Kwai, 1600 m, P. Weiss [ZMHB]; South Africa, dez.pensoft.net 72 Mpumalanga, Telperion Reserve, 1450 m alt. [-25.735, 28.985], 08.12.2019, beating, M. Wanat leg. [1, UWCP]; Gauteng, Pretoria, Wapadrand, 1540 m alt. [-25.847, 28.384], 09.12.2019, beating, M. Wanat leg. [1, UWCP]. Biology. This species is the only species in the genus that 1s frequently and broadly collected. It is found feeding and breeding in many host plants, such as Butyrospermum parkii, Madhuca latifolia, Mimusops caffra (all in Sapo- taceae), Olea capensis (Oleaceae), Garcinia (Clusiaceae) and Acacia (Fabaceae) (see Schedl (1961b)). It is notable that the majority of records are from Sapotaceae which is by far the most typical host plant family for the genus. Comments. The lectotype of X. /atus is identical, except for some of the setae on upper lateral part of the metaventrite which tend to be trifid or pentafid over a larger area rather than the typical trifid setae in the _X. sco- lytoides types. Xyloctonus niger Schedl, 1938 Figs 9, 12, 15 Xyloctonus niger Schedl, 1938 d: 452. Type material. Syntypes: Uganda, Entebbe [0.04, 32.42], 11-II-1938, P. Chandler [NHMUK, NHMW]. Diagnosis. Length 2.5 mm, 2.1< as long as wide, colour black, shiny; antennal club with two visible pro- curved sutures; frons glabrous; anterior margin of pro- notum with two raised teeth clearly longer than broad; all elytral interstriae carinate to posterior elytral margin; strial and interstrial punctures very shallow making walls of carinae rather smooth and shiny; scutellar shield a rounded button, clearly detached from the surrounding elytra; elytral suture with bulgy locking mechanism be- hind scutellar shield; setae on lateral metaventrite bifid. Distribution. Uganda. Biology. Known from the two collections in Uganda; the non-type series were dissected from 7abernaemon- tana holzkii (Apocynaceae) (see Menier (1974)). Comments. This species is very similar to X. scolyt- oides, but can be distinguished by the smooth and shiny interstrial carinae which is not indented along the carina wall, the glabrous frons and the consistently bifid setae on the lateral part of the metaventrite. The bimarginatus group All species (except X. opacus and X. punctatus) have in- terstriae 9 curved and continued to the elytral suture such that none of the interstriae 1-8 reaches the apical margin (Figs 1-4); thereof the name ‘bimarginatus’ . In the two de- viant species, the gap between the ninth interstriae and the apical margin nearest apex is so tight that interstriae 1—3 apparently reach the apical margin (Fig. 20). Nine species have exactly two raised teeth at the anterior margin of the pronotum, whereas another group of six species have four raised teeth along the anterior margin of the pronotum. dez.pensoft.net Bjarte H. Jordal: Taxonomic revision of Xyloctonus Species with two-spined pronotum Xyloctonus opacus Schedl, 1957 Figs 16, 19, 22 Xyloctonus opacus Schedl, 1957: 43. Type material. Holotype: Ruanda [Rwanda], Ihembe, 29-VIII-1952, Dr. Sched] [RMCA]. Diagnosis. Length 1.9-2.1 mm, 1.9-2.0x as long as wide, colour black, dull; antennal club with one visible procurved suture; frons finely pubescent; anterior margin of pronotum with two raised teeth; elytral interstriae 1-3 continue to posterior elytral margin, interstriae 4—8 ter- minate in the transverse interstriae 9 that merge with api- cal margin at level of interstriae 3; scutellar shield rough, weakly impressed in middle; elytral suture straight (me- sal locking mechanism normal). Distribution. Rwanda. Previous reports from Madagascar (Schedl 1977) are X. biseriatus [NHMW]. Biology. Collected from Chrysophyllum (Sapotaceae) branches about 2—8 cm in diameter (Sched! 1961b). Egg tunnels were cut transversely to the grain and the number of larvae ranged between 14 and 44 (n= 4). Xyloctonus punctipennis Eggers, 1939 Figs 17, 20, 23 Xyloctonus punctipennis Eggers, 1939: 16. Type material. Holotype: Somalia, Basso Ganana [-0.6, 41.7], VU-VIUI-93, V. Bottago [USNM]. Diagnosis. Length 1.8—2.4 mm, 2.0—2.1* as long as wide, colour brown, shiny; antennal club with two visible procurved sutures; frons with scant fine setae; anterior margin of pronotum with two raised teeth; elytral inter- striae 1-3 continue to posterior elytral margin, interstriae 4—8 terminate in the transversely curved interstriae 9 that merge with the apical margin at level of interstriae 3; scute- llar shield smooth, weakly impressed in middle; elytral su- ture with bulgy locking mechanism near scutellar shield. Distribution. Somalia. Xyloctonus biseriatus Schedl, 1953 Figs 18, 21, 24 Xyloctonus biseriatus Schedl, 1953: 76. Type material. Lectotype: Madagascar, Region de |’An- droy Ambovombe, Dr J. Decorse, 1901, 1 au 15 dec, 00 [MNHN]. Paralectotype: Madagascar sud, Fort Dauphin, Allaud, 1900 —I [MNHN]. Diagnosis. Length 1.5—2.0 mm, 1.8—-1.9x as long as wide, colour black, dull; antennal club with two visi- ble procurved sutures; frons glabrous; anterior margin Dtsch. Entomol. Z. 71 (1) 2024, 67-84 73 Figures 7-15. Dorsal, lateral and front view of X. scolytoides (7, 10, 13); paralectotype of X. /atus (synonym of X. scolytoides) (8, 11, 14); holotype of X. niger (9, 12, 15). of pronotum with two raised teeth; elytral interstriae 9 vation that mimics a dashed line; scutellar shield slightly curves before apex and continues transversely to elytral impressed in middle; elytral suture straight. suture; spaces between strial punctures with elongate ele- Distribution. Madagascar. dez.pensoft.net 74 Bjarte H. Jordal: Taxonomic revision of Xyloctonus TS. ps Figures 16—24. Dorsal, lateral and front view of holotype of X. opacus (16, 19, 22); paratype of X. punctipennis (17, 20, 23); X. biseriatus (18, 21, 24). dez.pensoft.net Dtsch. Entomol. Z. 71 (1) 2024, 67-84 New records. Madagascar, Ankarafantsika NP [-16.264, 46.828], 200 m alt. ex. Diospyros branch, 8 May 2015, B. Jordal, leg. [ZMUB]; Reserve speciale de l Ankarana, 22.9 km SW Anivorano [-12.93, 49.16], B. Fischer [CAS]. Biology. Previously collected in dry forests in the south of Madagascar and the new record from further north was also from a dry forest type. Specimens were collected twice from thin branches of Diospyros (Eben- aceae), about 3 cm in diameter. The egg tunnel was cut in the phloem and inner bark layers, transverse to the grain of wood. About 30—40 young tenerals and larvae were produced per brood (Table 2). Parents were not present at late larval stage. Colonisation densities were high, with only an average of 0.5 cm distance between egg tunnels. Xyloctonus pubifer Schedl, 1965 Figs 25, 28, 31 Xyloctonus pubifer Schedl, 1965a: 365. Type material. Holotype: South Africa, Port Elisabeth [-33.76, 25.45] [NHMW]. Diagnosis. Length 2.8—2.9 mm, 1.8—1.9x as long as wide, colour dark brown; frons finely pubescent; ante- rior margin of pronotum with two tiny, raised teeth; el- ytra with dense, fine micro-setae, interstrial and strial punctures dense and similarly sized; elytral interstriae 9 curves before apex and continues to elytral suture; scute- llar shield impressed in middle, bilobed, with bifid, short setae; elytral suture straight. Distribution, South Africa, Zambia. New records. South Africa, Western Cape Province, Natures Valley [-33.965, 23.562], 8 Nov. 2007, ex. Sid- eroxylon inerme, B. Jordal, leg. [ZMUB]; Eastern Cape Province, Van Stadens Resort, beating 18.11.2013, M. Wanat leg. [UWCP]. Biology. Collected multiple times in this study, from the bark layer of Sideroxylon inerme (Sapotaceae). Fe- males were found alone with larvae, the male was not observed, but presumably left their progeny at an earlier stage as observed in other species of the genus. Brood production ranged from 20-27 (n = 3). Flight times were observed in July and August in Zambia (Beaver and Loyt- tyniemi 1985) and estimated to be early October in South Africa, based on expected developing time for the larvae collected 1n this study. 79 Xyloctonus mauritianus Menier, 1974 Xyloctonus mauritianus Menier, 1974: 662. Type material. Holotype, male: Mauritius, Corps de gar- de [-20.26, 57.45], 20. V. 1934, J. Vinson [MNHN]. Diagnosis. Length 2.1—2.3 mm, 1.9 as long as wide, colour brown, elytra maculated; antennal club with one clearly visible and one faint procurved suture; anterior margin of pronotum with two raised teeth; scutellar shield impressed in middle, with two bulbs at anterior corners; elytral interstriae 9 curves before apex and continues to elytral suture; elytral suture straight. Distribution. Mauritius. Xyloctonus subcostatus Eggers, 1939 Figs 26, 27, 29, 30, 32, 33 Xyloctonus subcostatus Eggers, 1939: 15. Xyloctonus striatus Eggers, 1939: 18, syn. nov. Type material. Holotype: Deutsch Ost Afrika [Tan- zania], Bez. Tabora, Ngulu [-3.72, 32.46], vi. 1911, sammler W. Methner [USNM]. Paratypes of X. striatus: Mozambique, Sangadzé, Moulima [-17.4, 35.0], sur Aca- cia, 1928, P. Lesne [MNHN, NHMW]. Diagnosis. Length 1.7—2.8 mm, 2.0 as long as wide, colour brown; antennal club with two visible procurved sutures; male vertex with a simple pars stridens (Fig. 32); anterior margin of pronotum with two raised teeth; pro- notum slightly narrower than elytra; elytral interstriae 9 curves above the posterior margin of elytra and continues to elytral suture; interstriae lightly punctured; scutellar shield broad, slightly impressed in middle, roughly punc- tured; elytral suture with bulgy locking mechanism; setae on lateral upper part of metaventrite bifid. Distribution. Mozambique, Tanzania, Sudan, Demo- cratic Republic of the Congo (new country record) Guin- ea, Burkina Faso (new country record). New records. Burkina Faso, Comoe, Foret de Boulon, 270 m alt., 10.343, -4.510, 9.7.2006, F. Genier leg. [2, Geni- er coll.]; Democratic Republic of the Congo, Moba, 780 m alt., -7.030, 29.763, 01.10.1953, H. Bomans leg. [1, RMCA]. A specimen from the Democratic Republic of Congo [RMCA] was erroneously identified by Schedl as X. scolytoides. Biology. Collected from an Acacia (Fabaceae) branch (identified as_X. striatus). Two males were collected by a Table 2. Summary of reproduction in species of Xy/octonus published in: (1) this paper; (2) Schedl (1977); (3) Schedl (1961b). Species Host family Diam. (cm) Egg tunnel direction Brood size male leave female leave Xyloctonus aethiops'* Phyllanthaceae 1-4 longitudinal 21-40 egg larvae Xyloctonus biseriatus' Ebenaceae 2-4 transverse 30-40 egg or larvae larvae Xyloctonus pubifer' Sapotaceae 10-20 transverse 20-27 egg pupae Xyloctonus maculatus’ Sapotaceae 10-20 transverse 12-21 egg larvae Xyloctonus opacus® Sapotaceae 5-14 transverse 14-41 ? larvae Xyloctonus quadridens' Sapotaceae 1-20 transverse 30-50 ? ? dez.pensoft.net 76 Bjarte H. Jordal: Taxonomic revision of Xyloctonus Figures 25-33. Dorsal, lateral and front view of holotype of X. pubifer (25, 28, 31); paratype of X. subcostatus (26, 29, 32); paratype of X. striatus (synonym of X. subcostatus) (27, 30, 33). dez.pensoft.net Dtsch. Entomol. Z. 71 (1) 2024, 67-84 Malaise trap in Burkina Faso, in a dry bushland. The re- cords from south-eastern parts of the Democratic Repub- lic of the Congo, Sudan and Guinea are also from very dry forests below 1000 m altitude. Although present on one of Eggers ‘co-types’ (paratypes), the male pars stri- dens is here reported for the first time. Comments. Paratypes (‘co-types’) of X. striatus are identical to _X. subcostatus, except elytral interstriae 9 is a little less separated from the elytral apex. Xyloctonus bimarginatus Eggers, 1939 Figs 34, 37, 40 Xyloctonus bimarginatus Eggers, 1939: 17. Type material. Holotype: [Democratic Republic of the] Congo, Kundelungu [-10.25, 27.60], leg. Mme Tinaut [RMCA]. Diagnosis. Length 2.2—-2.6 mm, 1.9—2.0x as long as wide, colour brown, shiny; antennal club with two clearly-visible procurved sutures, a third and faint- er suture near the margin; frons with scant fine setae, vertex in males with pars stridens; anterior margin of pronotum with two raised teeth; elytral interstriae 9 curves before apex and continues to elytral suture, in dorsal view apical margin of elytra extending beyond margin of interstriae 9, finely serrated; scutellar shield impressed in middle, bilobed; elytral suture with bulgy locking mechanism. Distribution. Democratic Republic of the Congo. Comments. Only known from the type. It is not un- likely that XY. subcostatus is the same species. However, the type differs by having a longer flange at the elytral apex, in dorsal view extending beyond interstriae 9. It also has coarser punctures along the wall of the inter- strial carinae. Species with four-spined pronotum Xyloctonus maculatus Schedl, 1965 Figs 35, 38, 41 Xyloctonus maculatus Schedl, 1965b: 113. Type material. Paratype: South Africa, Cape Province, Port Elisabeth [-33.7, 25.6], VHI. 1960, ex Sideroxylon inerme, leg. J.S. Taylor [NHMW]. Diagnosis. Length 1.7—2.2 mm, 2.1—2.2x as long as wide, colour light to dark brown, with small, dark spots on elytra; antennal club with two visible procurved su- tures; eyes not divided, but deeply emarginated; anterior margin of pronotum with four raised teeth, median pair longest; elytral interstriae 9 curves before apex and con- tinues to elytral suture; scutellar shield rounded, with two tiny pits at anterior corners; elytral suture straight; elytral declivity long, nearly vertical; venter nearly straight. Distribution. South Africa. 7/ New records. South Africa, Western Cape Province, Natures Valley [-33.965, 23.562], 8 Nov. 2007, ex Sid- eroxylon inerme, B. Jordal, leg. [ZMUB]. Biology. Exclusively recorded from Sideroxylon in- erme (Sapotaceae). Fallen trees were crowded with males running on the surface in search of females sitting in new- ly-excavated tunnel openings. Mating occurred at the en- trance with only the posterior part of the female exposed. There was no nuptial chamber. Egg galleries were dense and males were guarding the entrance as long as the fe- male was accessible. Xyloctonus genieri sp. nov. https://zoobank. org/0977F970-815A-409A-BOOF-94EDD3 140070 Figs 36, 39, 42 Type material. Holotype: Burkina Faso, Comoe, Foret de Boulon [10.343, -4.510], 270 m alt., F. Genier leg., 10.7.2006, in Malaise trap [CMNC]. Diagnosis. Eyes emarginated, not divided. Antennal club with one faint procurved suture. Anterior margin of pronotum with four equally-sized, raised teeth. Description. Length 1.6 mm, 2.1 as long as wide; colour black. Frons convex, transversely impressed just above epistoma, surface finely rugose, vestiture scant. Eyes deeply sinuate, broadly emarginated. Antennal fu- niculus 6-segmented, club finely pubescent, basal suture procurved, others not visible. Pronotum coarsely asper- ate on anterior two-thirds, asperities transversely elon- gated; anterior margin with four raised teeth. Scutellar shield subquadrate, with four small tubercles. Elytral striae reticulated, punctures shallow, irregular; interstriae carinated throughout; interstriae 9 reaching elytral suture; elytral suture straight. Metaventrite and nearby sclerites and ventrite I with bifid setae. Distribution and biology. Only known from the type locality in avery dry bushland, collected in a Malaise trap. Etymology. Named after the coleopterist Francois Génier who collected the type specimen in Burkina Faso. Xyloctonus aethiops Schedl, 1953 Figs 43, 45, 47, 48 Xyloctonus aethiops Schedl, 1953: 77. Xyloctonus stenographus Schedl, 1961a, synonymy by Menier (1974). Type material. Lectotype, X. aethiops: Madagascar, Ankorika [-12.24, 49.36], K. E. Schedl, 1951 [MNHN]. Holotype of X. stenographus. Madagascar, Perinet [-18.93, 48.41], 28. XI. 1952, Dr. K. E. Schedl [MNHN]. Diagnosis. Length 1.3-1.6 mm, 2.0x as long as wide, colour dark brown; vertex with faint (false) pars stridens; antennal club with two visible procurved su- tures; anterior margin of pronotum with four raised teeth, median teeth longest; elytral interstriae 9 curves before apex and continues to elytral suture; elytral dez.pensoft.net 78 Bjarte H. Jordal: Taxonomic revision of Xyloctonus Figures 34—42. Dorsal, lateral and front view of X. bimarginatus (34, 37, 40); X. maculatus (35, 38, 41); X. genieri, holotype (36, 39, 42). dez.pensoft.net Dtsch. Entomol. Z. 71 (1) 2024, 67-84 ie es Figures 43—49. Dorsal, lateral and front view declivity and venter with strong spines, of X. aethiops (43, 45, 47, 48); X. quadricinctus, holotype (44, 46, 49). interstriae elevated, flattened, carinated on and near de- clivity only; scutellar shield transversely oval; elytral suture straight. Ventrite I swollen on median third of its posterior margin, ventrite II with four spines along the posterior margin. Distribution. Madagascar. New record. Madagascar, Andasibe, Mantadia Na- tional Park [-18.861, 48.447], 900 m alt. 15 May 2015, ex Uapaca twig, B. Jordal, leg. [ZMUB]. Biology. Two collections from known host were both in the same plant family Phyllanthaceae: Wielandia mi- mosoides (originally in Savia) (Schedl 1977)) and Ua- paca sp. This is the only Xy/octonus that cut their egg tunnels parallel to the grain of the wood. Three broods with larvae were dissected from a thin twig of 1 cm thick- ness and were without parents present. Brood size ranged between 21 and 28 (n = 3). Xyloctonus quadricinctus Schedl, 1941 Figs 44, 46, 49 Xyloctonus quadricinctus Schedl, 1941: 387. Type material. Holotype: [Tanzania] Usambara, Derema 850 m alt., 7.10.1891, Conradt S. [NHMW]. dez.pensoft.net 80 Diagnosis. Length 2.1 mm, 2.0x as long as wide, co- lour dark brown; antennal club with three visible pro- curved sutures; anterior margin of pronotum with four equally-long raised teeth; elytral interstriae 9 curves be- fore apex and continues to elytral suture; scutellar shield rounded, tuberculate; elytral suture straight. Distribution. Ghana, Nigeria, Tanzania. Biology. It has been collected from a Sapotaceae tree, Gambeya albida in Ghana (see Schedl (1961b)). Nothing else is known about its biology. Xyloctonus quadridens Schedl, 1953 Figs 50, 52, 54 Xyloctonus quadridens Schedl, 1953: 77. Type material. Syntypes: Madagascar, Mt. D’ Ambre, 1930, Sicard leg. [MNHN]. Diagnosis. Length 1.9-2.2 mm, 1.8—-1.9x as long as wide, colour black, dull; antennal club with two visible procurved sutures, a third suture intergrades with the apical margin of club; anterior margin of pronotum with four raised teeth; elytral interstriae 9 curves before apex and continues to elytral suture; scutellar shield rugose, slightly impressed in middle; elytral suture straight; male profemur with tiny spine on its ventral side. Distribution. Madagascar. New records. Madagascar, Andasibe, Mantadia Na- tional Park [-18.861, 48.447], 900 m alt. 15 and 16 May 2015, ex Labramia bojeri log, B. Jordal, leg. [ZMUB]; Reserve speciale de l’ Ankarana, 22.9 km SW Anivorano, B. Fischer [CAS]. Biology. The collection from Labramia_ bojeri (Sapotaceae) is the first known host for this species. Egg tunnels were cut transversely to the grain. Broods were old and only fully sclerotised adults were found. Identification key to the species of Xyloctonus Bjarte H. Jordal: Taxonomic revision of Xyloctonus Counts of larval mines ranged between 30 and 50 (n = 4). Comments. According to Menier (1974), the male should have a pars stridens on its vertex. However, none of the males at hand had this feature, despite the unique presence of a femoral spine (n = 4). Xyloctonus magnus sp. nov. https://zoobank.org/55896893-5EB7-41E2-A7B8-6F301C1E18C8 Figs 51, 53, 55 Type material. Holotype: Madagascar, Anjozorobe 11 km SE [-18.43, 47.94], Malaise trap, BLF2375, B. Fischer, leg. [CAS]. Diagnosis. Largest species in the genus, 3.4 mm long; scutellar shield longitudinally elongated as a heart-shaped scoop; sutural side of interstriae 1 with dense fine trifid setae. Description. Length 3.4 mm, 1.9x as long as wide, co- lour dark brown. Frons impressed just above epistoma, nearly glabrous. Antennal club with one strongly procurved suture, others faint; funiculus 6-segmented. Upper and low- er eye parts widely separated, roughly punctured between. Pronotum very broad, broader than elytra; anterior margin with four raised teeth, median pair slightly longer, asperities near summit as fine granules, intermixed with shiny punc- tures. Scutellar shield elongated, densely pilose, narrowly impressed to form a heart-shaped scoop. Elytral striae with transversely elongated punctures, spaced by longitudinally raised ridges, the whole stria appearing as a dashed line. EI- ytral interstriae 9 curves before apex and continues to elytral suture; elytral suture straight. Metaventrite and surround- ing sclerites, including ventrite I, with mainly trifid setae. Distribution. Madagascar. Biology. One specimen was taken in a Malaise trap. Etymology. Based on the Latin masculine adjective mag- nus, meaning large, referring to the body size of the species. 1 Elytral interstriae 9 terminates near lateral margin, interstriae 1-8 all reaching apical margin (Fig. 5)............ccccceeee ees 2 - Interstriae 9 reaching at least to interstriae 3, usually to the elytral suture, cutting off interstriae 1-8 which do not reach AB ICall Faro CRN StS: Lo cas2 aside ne sa er mmnte Wid tne ree eee, 2 Frons glabrous; pronotal teeth at the anterior margin longer than broad; elytral carinae smooth and shiny; punctures very shallow; colour shiny black (Uganda)..................0006 — Frons finely pubescent; pronotal teeth at anterior margin as long as broad; elytral interstriae with fine short setae on each side of deeply-punctured interstrial carinae; strial punctures deep; colour matt brown to dark brown (Afrotropical)...... nee ae atone Aaa gel i A seen eS,» CCR on Rca Re X. scolytoides ) Antekiomiiargin-el pronoun witipiour FarSed: Teeth GRieSes Gs SiGe .5me as Leela pep eee ease paella Peete eer 4 — Anterionanialre naw ithe hwo Farsed, tee thiGhips y GR lis). sow; 5: : a. x59 seroe Pees eae oy esa SANE See $5 Ea Pasaad eed Pasha cae Sees eee eG! 9 4 Eves sinuiate. motcivided (Rigs AeA ts wa szvelun eter ome adel ote hes poe gages er tegen Mes SalgMhul sale 2c Seater. ign eet ae 5 — Eyes completely divided, sometimes with a line of scattered ommatidia partly connecting them. ................cceceee cence ees 6 5 Elytra lightly coloured with dark spots; declivity steeply sloping (South Africa) ............cccccc ccc cc cc eceeaeeneeeeeaes X. maculatus - Elytra uniformly dark; declivity gently sloping (Burkina FASO) ...........ccc ccc cc ccc cence eceeeeceeeeeeeeeaeaeeneaeeseaeaneas X. genieri sp. nov. 6 Elytral interstriae on disc flattened, carinate near elytral apex; ventrite Il with four spines along the posterior margin; DOC ValLenonieomle ZannetlictladSaSoalps Bam tty 8. CU tek me cere tue tt oe Ree 28 oe ENC Eee ee oer are ore eet ee kone X. aethiops — Interstriae sharply carinate throughout; posterior margin of ventrites without longer spines; body size > 1.8 mm....... 7 dez.pensoft.net Dtsch. Entomol. Z. 71 (1) 2024, 67-84 81 7 Pronotal teeth along anterior margin spaced by more than width of a tooth (Fig. 44); elytral apex more broadly and deeply attenuated, apical tip of each elytron positioned between interstriae 3 and 4 (Ghana, Tanzania)............... X. quadricinctus — Pronotal teeth at margin nearly contiguous (Figs 50, 51); elytral apex shallowly attenuated with tip of each elytron po- SI MOMSCBOCLWECMENTCRS Late AN 1G ton roe 52 der pe cbc bante hy Stag nate Mees SeaUb es. 295.5 tlnie Sash SAUEE Belle roitdade ie ssa abeee O03, polite el mdake A) 8 8 Large species, length 3.4 mm; epistomal hair-like setae prominent, pointing forwards; scutellar shield longer than broad; ventral sclerites with mainly trifid setae (Madagascar) .............cccccccececeeceseeeeseeeseesessseeeeseeneeees X. Magnus sp. nov. — Smaller, length < 2.4 mm; epistomal hair largely recumbent, pointing downwards; scutellar shield broader than long; ventral sclerites with mainly bifid setae (Madagascar)..............cccccccscueceececeenececeeueceeeeeeueeesusuesesesausasseaeseeaes X. quadridens 9 Elytral interstriae 9 discontinued at the level of interstriae 3, interstriae 1-3 continue to apical Margin.................66 ake) _ Elytral interstriae 9 continues to interstria 1 with a clear gap between interstriae 9 and apical margin, all interstriae 1-8 CISGONEMUSEDESTOKS AD LCA AF ence ie -wrse a's sagtea se btrwtdnreae eine 4 Fact Uhyteten woe pie ats dF Hanke Ra hae win soace oP dgt Geetins 2 Wiel ediete irwelshe A Manse Uaefew ed cork ose 11 10‘ Elytra appearing shiny; elytral suture with bulgy locking mechanism near scutellar shield (Fig. 17) (Somalia)............... Oy ort aaa tate eee capable i uc ete Ny laste cabeok cates ers ex kg ell ee tage eae gy temic cate craic ohteas idea ete alt dean bh ala etehe cheerios ter obit X. punctipennis — Elytra appearing dull, reticulate, particularly inside punctures; elytral suture straight throughout (Fig. 16) (Rwanda).... aceein: B cites sae ec tn OR TEL ie Sen in Re A Re Se». a eRe eT ee ee IS: OM «cle ene ee X. opacus 11 _Elytral striae with longitudinal tubercle between transversely oval punctures which appears like a straight dashed line CIVIACLA CAS Cale): 5e8 est eck Lek Ba Ge MEAS ee CEES a es aN ee, Be ee AS Ee ee mW Soh at cin bee SEOs Meee pend sas ues Sen ae wee ae EEN X. biseriatus - Elytral striae with round punctures, without the dashed line patter n................cccccccceceececeeeeceeeececeeeseeaeceeeseseeasseeaseees 12 12 Elytral suture straight; pronotal asperities near summit as broad irregular ridges; interstriae with fine setae on each side Ct FEM CSIMLO MS all: Gale oath le sites. 328 hE oth ee ate AS Boia Ah CREE MEE! II Siete Ce etd Frosh ELE AMEN, AGS 8 cde ie ack eae Rass! 13 — Elytral suture with bulgy locking mechanism, pronotal asperities not much broader than tall; interstrial setae barely SOMES 5.7 ce 8 UL Demy ee, ear, oe Owe UE BD Tan oe Ane ASL Lee ne, ne SPA Bag oe ORO SRR owe aah MEE EE Bees om nate nL ae 14 13 Pronotal teeth at anterior margin longer than broad, strial punctures large, in a single row; body length 2.0-2.2 mm CIMIGUENPR TICES, Vir Seen i aeeveive dle ehe da parweat ee delnlehe or tadg ath Muay seildsneeed ined unbicy dechslnue peidaey Renee ee sidvae Red span iiter pe ciilaue area hae X. mauritianus - Pronotal teeth at margin not longer than broad; strial punctures small, in two confused rows; body length > 2.7 mm (QSrOun Ed abe a lig tors Walea's ag | 8]: ) Le eed cee tae FFE PERMIAN SU ces bone FEPETOU ON TUS vod oer tehes POPE PHMMSS YT Mt ore, bart FYE REVOUTL IVS olen taer PIPPUMNGA TTL Cavers, bey PEN X. pubitfer 14 Apical rim of elytra extends far beyond the transverse interstriae 9, forming a lip (Figs 34, 37) (Democratic Republic of {Ua ey 15101100 bene ae nf ENR a Le ERE A ae AE ean MERE De CRM Ae SRR ete A! ALS ORE ead 9 ie X. bimarginatus - Elytral interstriae 9 near elytral apex approximately at the same level as elytral apex (Burkina Faso and Guinea to Sudan, south-eastern Democratic Republic of the Congo, Mozambique, TanZania)...........ccccccccccccceeceeceneeeeceeeeeneens X. subcostatus Discussion are hatching and females at some undetermined time lat- er, but usually well before the young tenerals appear. The Biology rather aggressive mating behaviour observed in males of Xyloctonus species are easily recognised by their compact morphology which reflects a likely adaptation to avoid predators. When disturbed, they easily fall off the branch or trunk after retracting their tarsi into deep grooves on their tibiae, particularly the protibiae. The legs are, fur- thermore, strongly flattened and the metatibiae and femur fit into a depression of the metanepisternum and metaven- trite, which is carinated along its front edge. Observing their mating behaviour in the field reveals fast running of males on the bark to find a colonising female, with which he mates in the tunnel opening. He will, thereafter, guard the opening to prevent further access to the female by other males. This is a very exposed situation that in- creases the risk of being taken by predatory insects such as ants or even by insectivore birds. These beetles have an impressive reaction speed and fall off the log extremely quickly. Species in Xy/octonus and other Xyloctonina are, therefore, amongst the most specialised with morphol- ogies deviant from the average bark beetle body shape (Schedl 1961b). Both males and females stay only for a short time with their broods (Table 2). Males usually leave before the eggs several species seems connected to the external location of mating which involves a high risk of predation. It 1s likely that the early escape from the egg gallery provides further opportunities for mating and perhaps compensates for the high predation risk during mate search. This be- haviour was most clearly demonstrated by X. maculatus which may establish a new nest on the same log. Limited parental care with the potential for multiple matings is perhaps also motivated by the generally low brood sizes compared to the average for bark beetles (Browne 1961), although low brood size could also be a consequence of limited parental care. The low number of known host plants, restricted to a handful of plant families, indicates a high level of host specialisation in this genus. Six of the ten species with known host records were taken from plants in Sapotace- ae. Mono- and oligophagy are typical for bark beetles as opposed to the broader range of host plants used by am- brosia beetles (Beaver 1979; Hulcr et al. 2007). The few host plants recorded are not a serendipitous artefact from rare collecting events as multiple collections over time and from localities far from each other were from the same host (Schedl 1957, 1961b, 1977; this study). Five of dez.pensoft.net 82 ‘ eal Figures 50-55. Dorsal, lateral and front view of male X. guadridens (50, 52, 54); X. magnus, holotype (51, 53, 55). the six species reported in this study were collected mul- tiple times in one field work session, suggesting that these species are not extremely rare, although X. scolytoides is the only one collected more than four times. Plastic dimorphism A stridulatory apparatus is sometimes present, but varies in size and distinctness. Menier (1974) reported the pres- dez.pensoft.net Bjarte H. Jordal: Taxonomic revision of Xyloctonus ence of a stridulatory file in the upper frons of male X. quadridens, which was not observed in the new material. The males of this species have a spine on the ventral side of the femur, but, nevertheless, there was no pars stridens present in any of the new specimens collected. Multiple series of X. subcostatus also indicated that at least some males exhibit a pars stridens, previously not reported. Somewhat intermediate 1s X. aethiops which has a partial- ly developed and likely a false pars stridens, a feature not seen in the type material of this species. One should not Dtsch. Entomol. Z. 71 (1) 2024, 67-84 exclude the possibility that cryptic species may exist and which differ in their stridulatory apparatus. However, such crypsis seems less likely given their otherwise identical morphology. To firmly conclude on these matters, DNA from multiple populations is needed to test this hypothesis. Biogeography Restricted use of host plants is associated with limited geographical distributions and high endemism in nearly all species of Xy/octonus. Amongst the 15 currently-rec- ognised species, only four have a broad distribution including two or more biogeographical regions. Howev- er, only one of these have trustworthy records from both western and eastern to southern parts of Africa. The core distribution is in the Zambesian region and four species are found endemic to Madagascar and one on Mauri- tius. Unfortunately, many of the older samples from the Zambesian region were unsuitable for DNA sequencing and, therefore, limited the biogeographical inference in the BBM analysis. It was, nevertheless, clear that Xv/oc- tonus differs strongly from Ctonoxylon which unequiv- ocally demonstrated a Congolian ancestry, with much more recent and repeated colonisations of Madagascar and the southern parts of Africa. It is likely that broader sampling of Xyloctonus will further confirm a single ancient colonisation of Mada- gascar during the Eocene. This was a favourable time to colonise the island due to the trade winds blowing pri- marily in an eastern direction (Yoder and Nowak 2006; Ali and Huber 2010; Jordal 2021b; Ali and Hedges 2022), but examples of colonisations in the opposite direction are found in, for example, xyleborine (Eliassen and Jordal 2021) and micracidine beetles (Jordal 2021b). The oppo- site pattern is apparently the norm for Ctonoxylon which revealed three independent colonisations with subsequent speciation during the mid- or late Miocene. Each of the two undescribed Malagasy species and one that did not provide DNA data, are all fairly similar to, but distinct from, the African mainland sister species (unpublished manuscript). It is, therefore, possible that these have col- onised Madagascar even more recently than that which the dated phylogeny indicates. It appears more and more clear that insects are not in- fluenced by historical trade winds to the same degree as in non-volant animals (Crottini et al. 2012; Samonds et al. 2012). On the other hand, one needs to keep in mind that most insect groups never managed to settle on Madagas- car, for example, G/ostatus which is found in rather similar ecological niches on the African continent (Jordal 2023). This genus shows a strong core distribution in the Zambe- sian region (see Fig. 6), with one or few dispersal events towards the southern part of Africa. This pattern is rem- iniscent of the one for Ctonoxylon, whereas Xyloctonus may have colonised southern Africa from Madagascar, a pattern known from several scolytine beetle groups (Jord- al 2013; Eliassen and Jordal 2021; Jordal 2021b). With 83 a steady increase in biogeographic data for Afrotropical scolytine beetles, it seems clear that patterns are variable and not particularly correlated with trade winds. A similar pattern is found in plants with windborne seeds, telling us that prevailing wind systems possibly vary more than postulated (Ali and Huber 2010; Ali and Hedges 2022). Acknowledgements The author thanks, in particular, the staff at the California Academy of Sciences and Fran¢ois Génier at CMNC for samples containing new taxa. Additionally, many thanks to the curators at the institutions listed for access to other un- identified material and loan of type specimens. Collecting and export permits for Madagascar were kindly facilitated by MICET and granted by Direction generale de |’ environ- ment et des forets 2012, 2015 and 2018. Permit for collect- ing and research in the Cape Provinces of South Africa 2006 was granted by Cape Nature no. AAA-004-00062-0035. References Ali JR, Hedges SB (2022) A review of geological evidence bearing on proposed Cenozoic land connections between Madagascar and Af- rica and its relevance to biogeography. 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