Ctonoxylon auratum Hagedorn, 1910: 4, subsequent designation by Hopkins (1914): 119.

Typical for subtribe Xyloctonina, with stout and rounded body shape, eyes divided, and protibia on its anterior face with a deep groove. Antennal funiculus 7-segmented, club with oblique lateral septum, sutures faint or obscure, asymmetrical; pronotum with pair of teeth in females at the anterior margin, in males just behind anterior margin, teeth occasionally fused, or divided into four parts. Elytral declivity steep, abdominal ventrites flat or gently rising towards elytral apex.

Dimorphism between males and females has not been clearly formulated in previous work. Nevertheless, the male pronotum has a pair of raised teeth located a little behind the front margin whereas the females have the pair of teeth at the margin and slightly closer to each other. Occasionally the male frons is also slightly modified in some species, either with the central area shinier, or with longer setae, or with patterns of transverse wrinkles. In at least one species (C. montanum) the degree of inflation of the elytral apex differs between the sexes (Schedl 1972).

Recent phylogenetic analyses (Jordal 2023) supported a separate position of Ctonoxylon in Xyloctonina as the sister lineage to the three other genera Scolytomimus, Xyloctonus, and Cryphalomimus.

Holotype , male: Congo Belge [Democratic Republic of the Congo], Yangambi, 2.VII.1952, K.E. Schedl leg. [NHMW].

Length 1.5 mm, 2.1× as long as wide, colour pale brown. Eye parts closely separated (by scapus thickness); pronotal eye scraper weakly developed, faint carina near anterior lateral margin from scraper to coxa, without associated groove or propleural pit; scutellar shield at same level as elytra; elytral striae impressed, punctures slightly elongated, separated by 2–3× their diameter; elytral vestiture consisting of long hairlike setae separated within rows by a little less than their length; elytral apex slightly extended with sharp tubercles along the posterior margin.

Democratic Republic of the Congo.

Nothing known except collected in a tropical lowland rainforest.

Holotype , female: Kamerun, Soppo, 800 m, XII 1912, v. Rothkirch S.G. Holotype of C. dentigerum, male: Spanish Guinea [Equatorial Guinea]. [both in NHMW].

Length 3.1–3.2 mm. 2.1–2.2× as long as broad; colour brown. Upper and lower eye parts separated by more than width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; scutellar shield at level with elytra; striae slightly impressed; main interstrial setae and ground vestiture similar and evenly distributed, each seta a little shorter than width of an interstriae; elytral apex slightly emarginated; resting position of mesotibiae marked on metaventrite.

Cameroon, Equatorial Guinea, Tanzania (new country record).

Tanzania, Morogoro, Kimboza Forest Reserve [GIS: -7.023, 37.806], S.S. Madoffe, leg. [1, NHMUK].

Using the principle of first reviser the name festivum is given priority as there is nothing particularly dentigerous about this species. Differences noted between the holotypes of C. dentigerum and C. festivum are likely due to sexual dimorphism, with the male dentigerum having the anterior pair of teeth on pronotum a little behind the anterior margin and in festivum along the front margin. Minor variation in the length of elytral setae can also be due to dimorphism, or simply due to variation between individuals as often observed in similar species. Biology unknown, except collected in low- to mid-altitude rainforest.

Figures 12–20. 

Dorsal, lateral, and front views of 12, 15, 18 Ctonoxylon hirtellum male holotype 13, 16, 19 Ctonoxylon festivum female holotype, and 14, 17, 20 Ctonoxylon dentigerum male holotype, syn. nov. (= Ctonoxylon festivum).

Holotype : Kamerun [ZMHB]; ‘type’ of C. flavescens opacum: Kamerun [SDEI]. Holotype of C. flavescens usambaricum: Mkulumusiberg 1000 m, bei Sigi Ostafrika [NHMW].

Length 2.2–3.1 mm. 2.1–2.3× as long as broad; colour brown, dull. Upper and lower eye parts separated by more than width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; scutellar shield at level with elytra; striae distinctly impressed; interstrial setae bristle-like, variable in length and placed irregularly in partly confused rows, without ground vestiture; elytral apex slightly emarginated; resting position of mesotibiae marked on metaventrite.

Guinea, Ghana, Cameroon, Democratic Republic of the Congo, Gabon, Uganda (new country record), Tanzania.

Uganda, Masindi, Budongo, Nyabyeya [GIS: 1.673, 31.540], 3. July. 1998, ex Ficus branch, B. Jordal, leg. [ZMUB]; Budongo, BFP Station, Sonso [1.723, 31.545], 6.10.2004, T. Wagner leg. [1, ZFMK]; Kichwamba [0.71, 30.20], 25.04.1968, P.J. Spangler [1, USNM]; Cameroon, Limbe, Ekande [GIS: 4.081, 9.172], 1000 m. alt., 20. Nov. 2007, ex Cola acuminata standing tree, B. Jordal, leg [ZMUB]; [Ghana], ‘Gold Coast’, Takoradi [4.90, -1.75], 10.12.1946, ex bark of mahogany logs [Khaya ivorensis] [4, USNM].

Very little is known about this species despite frequent collections from many African countries. This study reports Cola as a new host plant genus in the same family Malvaceae as for the previously recorded Triplochiton (see Schedl 1961). Another new record from Ficus is in line with some other collections of closely related species taken from various Moraceae genera (see below). It is also reported here from African mahogany logs (Meliaceae), demonstrating a rather broad assembly of host plants. Records are generally from the bark of larger branches and trunks where the maternal egg tunnel is cut longitudinally. The male may stay at least until eggs are hatched, but not much longer (Table 5). Brood size is moderately large, with 19–45 eggs or larvae.

This species and the next three are morphologically very similar and can easily be confused. DNA sequence data for COI and 28S from three of the species nevertheless clearly separate them (Table 4, Fig. 11). Eastern and western populations of C. flavescens are also deeply, albeit less, diverged in the mitochondrial COI gene, but, more importantly, identical at the nuclear 28S gene. It is advisable to apply DNA sequence data to identify species in this complex group. The record from Madagascar is likely confused with the new species C. tuberculatum described in this work.

Holotype and additional non-types from the type locality of C. bosqueiae: Ghana, Bobiri, Kumasi [NHMUK].

Body length 2.2–2.5 mm, 2.2–2.3× as long as broad; colour dark brown, dull. Upper and lower eye parts separated by more than width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; scutellar shield at level with elytra; striae distinctly impressed; interstrial setae bristle-like, variable in length and placed irregularly in rows, without ground vestiture; elytral apex entire; resting position of mesotibiae marked on metaventrite.

Ghana.

This species is very similar to C. flavescens but differs by the nearly closed gap between the apical tip of each elytron. Genetic data are needed to test the validity of this species. It is only known from the type locality in Ghana. Other published records are removed on the suspicion being the similar and commonly occurring C. flavescens or C. hirsutum. The hostplant Trilepisium is in the plant family Moraceae, similar to many other host records for the flavescens group.

Syntype (metatype sensu Eggers): Kamerun, Conradt leg. [NHMW].

Body length 2.5–3.0 mm, 2.2–2.3× as long as broad; colour pale brown. Male frons slightly flattened on lower half, very slightly shrivelled, surface finely rugose above, female frons smooth, vestiture in the frons of both sexes consisting of fine setae. Eye parts separated by the size of upper eye; antennal club sutures not clearly marked; anterior lateral margin of prothorax at middle with acute eye scraper; a sharp carina running from eye scraper to near procoxa; propleural pit absent; elytral vestiture on each interstriae consisting of two irregular rows of slightly curved bristle-like setae and scattered very fine hair-like setae; elytral suture straight; elytral apex slightly emarginated, a few small and sharp tubercles along the posterior margin. Metanepisternum with mixed short plumose and hair-like setae; metaventrite with simple hair-like setae; these sclerites on its anterior third glabrous, with a vertically curved swollen trace of mesotibia’s resting position.

Ghana, Cameroon, Democratic Republic of the Congo, Gabon.

Cameroon, Ekande, 5 km N Limbe [GIS: 4.081, 9.172], 1100 m alt., ex unknown liana, 18.XI.2007, A. Breistøl, leg. [1, ZMUB]; Cameroon, Mbalmayo Forest Reserve, Eboufek [GIS: 3.499, 11.883], 28.07.1993, FIT [1, NHMUK]; Republic of the Congo, 40–60 km ESE of Bomassa [2.04, 16.59], 18.04.1993, D.H. Chadwick leg. [1, USNM].

Figures 21–29. 

Dorsal, lateral, and front views of male 21, 24, 27 Ctonoxylon flavescens 22, 25, 28 Ctonoxylon bosqueiae holotype, and 23, 26, 29 Ctonoxylon hirsutum stat. rev.

All records are from lowland rainforest sites in the western parts of Africa. It was previously collected from latex rich lianas (Schedl 1961). In the current study two further specimens were dissected from a dead liana together with specimens of C. pilosum sp. nov. One specimen was also collected in a flight intercept trap [NHMUK].

Very similar to C. flavescens, except the elytral interstriae have fine pubescent ground vestiture and the two teeth near the anterior margin of the pronotum are subcontiguous. Previously designated as a variety of C. flavescens, but with a type designated, a subspecies name given and published by Hagedorn (1910). Sufficient diagnostic features as detailed by Eggers (1920), and molecular data demonstrating deep divergence from C. flavescens (Table 4), strongly support species status for the name hirsutum. Records from Ghana and Gabon (see Schedl 1961) could not be verified but these seem likely given several validated records from nearby countries.

Holotype , male: Madagascar, Diana prov., Montagne d’Ambre [GIS: -12.54, 49.17], 1000 m alt., ex Ficus branch, 03.11.2019, B. Jordal, leg. [ZMUB]. Allotype [ZMUB] and paratype [NHMW]: same data as holotype.

Two teeth along the anterior margin of pronotum separated by more than width of a tooth; scattered interstrial setae separated within uniseriate rows by more than their length; posterior margin of elytra and declivital interstriae with sharp tubercles, largest tubercles on interstriae 1 and 3.

Male. Body length 3.0–3.1 mm, 2.1–2.2× as long as broad; colour brown. Frons flattened from upper level of eyes to epistoma, surface shrivelled; vestiture of fine short setae. Eyes divided, each part separated by a little more than size of upper half. Antennal funiculus 7-segmented; club setose, sutures and septum barely indicated. Pronotum coarsely asperate on anterior three quarters, two front teeth separated by little more than width of a tooth, located behind the margin. Anterior lateral margin of prothorax at middle with prominent eye scraper; a sharp carina running from eye scraper to near procoxa; propleural pit absent. Scutellar shield wider than long, oval. Elytral striae impressed, punctures irregular and small; interstriae rounded, densely micropunctate, vestiture consisting of uniseriate rows of slightly curved bristle-like setae and fine dense ground vestiture along the suture; elytral suture straight; elytral apex slightly emarginated, along the posterior margin and at each declivital interstriae with small sharp tubercles, at interstriae 1 and 3 tubercles 2–3× larger. Metanepisternum with mixed short bifid and longer bristle-like setae; metaventrite with simple hair-like setae; these sclerites on its anterior third partly glabrous and with small bifid setae, and with a swollen trace of mesotibia’s resting position. Female as in male, except anterior pair of teeth more closely placed and located along the anterior margin of the pronotum, and surface of the frons smooth.

The Latin adjective tuberculatus in its neuter form, reflecting the tubercles on declivital interstriae which are more prominent than in related species.

Only known from the holotype locality in Madagascar where it was collected from very thick bark of a fallen Ficus branch (Moraceae), 7 cm in diameter. Two pairs were collected at the early stage of tunnel construction, including a mating niche with a short egg tunnel.

Previous records of C. flavescens from Madagascar are most likely C. tuberculatum as these two species are very similar. This could also be the case for records of C. montanum (recorded as C. longipilum), in which the female mainly differs by the more closely set anterior teeth on the pronotum, and the stouter body. These two species are therefore removed from the list of Malagasy species.

https://www.barkbeetles.info/photos_target_species.php?lookUp=7979. https://www.barkbeetles.info/photos_target_species.php?lookUp=2193.

Holotype female: Kamerun, Buea, XII.10, Hintz, leg. Type 60341 [USNM]. Holotype of Ctonoxylon longipilum, female: [Tanzania] Mulange, Br. O. Afr. Type 60340 [USNM]. Holotype of C. nodosum, male: [Democratic Republic of the Cogo] Congostaat, Mongbwalu [1.93, 30.05], [1200 m alt.] Mm Scholtz [RMCA].

Length 3.2–3.6 mm. 2.0–2.1× as long as broad; colour brown. Upper and lower eye parts separated by 1.5× the width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; scutellar shield at level with elytra; striae distinctly impressed, interstriae rounded, interstrial setae curved and bristle-like, variable in length and scattered irregularly within rows, denser on declivity, without ground vestiture; elytral apex in females slightly extended, entire, in males apical interstriae 1 and 2 fused and strongly inflated; resting position of mesotibiae marked on metaventrite.

Ivory Coast, Ghana, Nigeria, Cameroon, Democratic Republic of the Congo, Uganda, Kenya, Tanzania

Ghana, Ashanti region, Kwadaso, 320 m., N6.42’ – W1.39’, Dr. S. Endrödy-Younga, mixed light, 25.II.1969 [1, NHMW]; Ghana, Western Region, Ankasa, Nkwanta Camp, 8.6.2005, KB Miller, leg. [1, ZMUB]; Nigeria, Ibadan [7.40, 3.85], 01.11.1964, M.L. Jerath leg. [2, USNM]; Nigeria, Ife, W. State [7.48, 4.48], 01.08.1971, T. Medler [3, USNM]; Cameroon, Libamba, 10 km E of Makak [3.54, 11.09], 11.02.1974, black light, J.A. Gruwell leg. [1, USNM].

Type specimens of C. longipilum and C. montanum are near identical and synonymised. The first species has only slightly longer curved elytral setae, but this feature varies between specimens. All specimens of the two nominal taxa are females as characterised by the pair of raised teeth along the anterior margin of the pronotum. Previously Schedl (1972) synonymised C. nodosum with C. longipilum due to the presumed sexual dimorphism expressed in the inflated elytral apex and the lack of raised teeth along the pronotal margin. Schedl’s view is supported and the synonym C. nodosum is therefore moved to C. montanum.

Figures 30–38. 

Dorsal, lateral, and front views of 30, 33, 36 Ctonoxylon tuberculatum sp. nov. male holotype 31, 34, 37 Ctonoxylon longipilum female (= C. montanum), and 32, 35, 38 Ctonoxylon nodosum male holotype (= C. montanum).

The record from Madagascar as C. longipilum (see Schedl 1977) is likely a misidentified female specimen of C. tuberculatum sp. nov. and is removed from the distribution list. Basically nothing is known about its biology except coming to light at lower to middle altitudes.

Holotype : Kamerun [ZMHB]. Holotype C. conradti, female: [Tanzania] Insel Ukerewi [NHMW].

Length 3.4–3.8 mm. 2.0–2.1× as long as broad; colour brown. Upper and lower eye parts separated by 1.5× the width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; scutellar shield at level with elytra; striae weakly impressed; interstrial setae sort, bristle-like, dense, confused with similar type of ground vestiture; elytral apex slightly emarginated; elytral suture buckled on disk; resting position of mesotibiae marked on metaventrite.

Liberia (new country record), Ivory Coast, Nigeria, Cameroon, Equatorial Guinea, Gabon, Democratic Republic of the Congo, Angola, Tanzania.

Liberia, Suakoko [6.98, -9.54], 28.1–5.5.1952, light trap, Blickenstaff leg (47); Cape Mount [6.72, -11.34], 1940, M. Mann (1) [USNM]; Nigeria, Ife, W. State [7.48, 4.48], 25.03.1969, J.T. Medler [1, USNM]; Cameroon, Yangamo, 100 km NE Bertoua [GIS: 5.00, 14.025], 25.03.1984, Kunze & Nagel, leg. [ZFMK]; 10 km S of Tongo [4.91, 10.77], 02.03.1972, black light, J.A. Gruwell [USNM].

The holotype of C. conradti was compared to a specimen of C. camerunum determined by Hagedorn in ZMHB, which is possibly the holotype. The type of C. conradti has slightly shorter elytral setae and is less shiny than camerunum, but this is very likely within species variation.

Holotype : Kamerun, coll Strohmeyer [SDEI].

Length 3.8–4.1 mm. 1.9–2.0× as long as broad; colour dark brown. Upper and lower eye parts separated by 1.5× the width of upper part; pronotal eye scraper acutely pointed; a sharp carina running from scraper to procoxa, without associated groove or propleural pit; anterior pair of teeth on pronotum much larger than other asperities; scutellar shield at level with elytra; striae weakly impressed; interstrial setae short and bristle-like, dense, confused with similar type of ground vestiture; elytral apex nearly entire, very slightly emarginated; elytral suture buckled a little behind scutellar shield; resting position of mesotibiae marked on metaventrite.

Figures 39–47. 

Dorsal, lateral, and front views of 39, 42, 45 Ctonoxylon camerunum female 40, 43, 46 Ctonoxylon cornutum female holotype, and 41, 44, 47 Ctonoxylon torquatum sp. nov. female holotype.

Cameroon.

Holotype , Madagascar, Toliara, Sept Lacs [GIS: 23.527, 44.155], MGF076, 02.03.2002, B. Fischer, leg. [CAS]. Paratypes, same data as holotype [CAS (2), NHMW (2), MSUC (2), ZMUB (2)].

Protibiae with shallow anterior groove of depth < 1/3 width of the tibia; anterior margin of prothorax from coxa to top with an indented row of deep circular pits; scutellar shield and elytral suture with soft white setae; elytral apex with pair of tubercles.

Body length 1.9–2.5 mm, 2.0–2.1× as long as broad; mature colour dark brown. Frons flattened from just below upper level of eyes to epistoma, surface finely punctured and granulated, central third smooth and impunctate; vestiture of fine short setae, nearly glabrous in middle. Eyes divided, each part separated by 2/3 the size of upper half. Antennal funiculus 7-segmented; club with two asymmetrically and strongly procurved sutures, suture one partly grooved, club segments 1 and 2 each with a dark septum clearly indicated. Pronotum asperate on central half of anterior three quarters, two front teeth separated by little less than width of a tooth, located at the margin, one additional pair of larger teeth a little behind the front teeth. Lateral anterior margin of prothorax with indented row of deep circular pits running from pronotal teeth to coxa; propleural pit longitudinally elongated, located between coxa and lateral costa on pronotum. Scutellar shield slightly detached from elytra, slightly sunken, broader than long, with fine white setae. Elytral striae impressed, punctures round or subquadrate, spaced by less than their diameter; interstriae raised, profile rounded, cuticle rough, vestiture consisting of confused, dense, bristle-like setae, with densely placed soft white setae along a straight elytral suture; apex with a pair of small tubercles. Metanepisternum with short plumose setae; metaventrite with scattered simple setae. Protibiae on anterior face with shallow groove for reception of tarsus, ~ 1/3 as deep as width of tibia.

The Latin adjective torquatus in its neuter form, meaning adorned with a collar, referring to the row of deep pits along the front margin of the prothorax.

Only known from a long series of specimens collected at the type locality in the dry forest of south-western Madagascar.

Holotype : Kamerun, Conradt [leg.], coll Kraatz, Hagedorn det. [SDEI].

Length 2.1–2.2 mm. 2.4–2.5× as long as broad; colour brown. Eyes divided, separated by 2/3 the width of upper part; setae in frons mainly scale-like; anterior margin of pronotum with two teeth fused; anterior margin of prothorax from top to coxa with row of deep circular pits; propleural pit present; elytral vestiture of irregular interstrial rows of scalelike setae mixed with smaller and softer bristle-like setae, appearing somewhat fluffy; elytral apex emarginated; protibiae on anterior face with shallow groove, depth ~ 1/3 of tibia width.

Figures 48–56. 

Dorsal, lateral, and front views of 48, 51, 54 Ctonoxylon auratum female holotype 49, 52, 55 Ctonoxylon pilosum sp. nov. female holotype, and 50, 53, 56 Ctonoxylon pygmaeum female syntype [ZMHB].

Cameroon, Democratic Republic of the Congo.

The female holotype of this species is located in Muncheberg [SDEI], not Berlin as stated in Wood and Bright (1992).

Holotype , female: Cameroon, Ekande near Limbe [GIS: 4.081, 9.172], 1100 m alt., 18.11.2007, ex thin liana, A. Breistøl, leg. [ZMUB]. Allotype [ZMUB] and one paratype [NHMW]: same data as holotype.

Protibiae with shallow anterior groove of depth < 1/3 the width of the tibia; anterior margin of prothorax from coxa to top with indented row of deep circular pits; elytral interstriae with dense, soft, golden ground vestiture in addition to longer, curved, bristle-like main setae.

Body length 1.4–1.8 mm, 2.2–2.4× as long as broad; colour yellowish brown. Frons flattened from just below upper level of eyes to epistoma, surface finely punctured below, reticulate above, vestiture consisting of sparse, fine, short setae. Eyes divided, each part separated by 2/3 the size of upper half. Antennal funiculus 7-segmented; club with two asymmetrically and strongly procurved sutures, suture one partly grooved with a dark partial septum along the front margin of the suture. Pronotum coarsely asperate on central two-thirds of anterior two-thirds, two front teeth at margin subcontiguous, not particularly larger than other asperities. Anterior lateral margin of prothorax with indented row of deep circular pits running from the anterior pronotal teeth to coxa; a round propleural pit located between coxa and lateral costa on pronotum. Scutellar shield flush with elytra, with fine golden dorsal setae. Elytral striae impressed, punctures round, irregularly sized and spaced; interstriae flat to slightly rounded, vestiture consisting of irregular rows of curved bristle-like setae, with ground vestiture consisting of more densely placed, soft, golden, hair-like setae; elytral suture straight, apex weakly emarginated. Metanepisternum and upper metaventrite with short plumose setae, simple and longer setae elsewhere. Protibiae on anterior face with shallow groove for reception of tarsus, ~ 1/3 as deep as width of tibia.

Male nearly identical to female, except frons more distinctly impressed below upper level of eyes, and the anterior pair of pronotal teeth is located just slightly behind the front margin.

The Latin adjective pilosus in its neuter form, meaning hairy, referring to the dense ground vestiture of fine, short, golden setae.

Only known from the type locality in Cameroon where specimens were collected from a climbing plant, ~ 2 cm in diameter.

Syntypes , females: Kamerun, Soppo, 800 m., XII 1912, v. Rothkirch S.G. [ZMHB, NHMW].

Length 1.6–1.7 mm. 2.2–2.4× as long as broad; colour dark brown. Eyes divided, separated by half the width of upper part; frons nearly glabrous, reticulate; pronotal asperities broadly distributed on anterior three-quarters; lateral anterior margin of prothorax from top to coxa with row of shallow irregular pits; propleural pit present just above coxa; elytral vestiture of regular interstrial rows of scalelike setae only; elytral apex expanded by pair of elongated prong-like tubercles; protibiae on anterior face with deep groove.

Cameroon.

Holotype , male: [Democratic Republic of the] Congo Belge, Stanleyville [Kisangani], 19.6.1952, K.E. Schedl [NHMW].

Length 3.5 mm. 2.2× as long as broad; colour dark brown and black. Eyes divided, separated by the size of upper part; head black, frons reticulate, with scattered short setae; pronotal asperities broadly distributed on anterior three-quarters; lateral anterior margin of prothorax from middle part to coxa with shallow irregular groove; propleural pit presumably present; elytral vestiture of multiple confused rows of short interstrial scale-like setae; elytral apex expanded by pair of elongated prong-like tubercles; protibiae on anterior face with shallow groove of depth 1/3 the width of tibia.

Democratic Republic of the Congo.

Holotype , male: Kamerun, Conradt [leg.], coll Kraatz, Hagedorn det. [SDEI].

Length 2.4–2.5 mm. 2.1× as long as broad; colour brown. Eyes divided, separated by slightly more than the size of upper part; frons lightly punctured, reticulate, glabrous; pronotum strongly domed, summit near posterior margin; pronotal asperities low, broad, subcontiguous, distributed on anterior three-quarters; lateral anterior margin of prothorax from middle part to coxa with shallow irregular groove; propleural pit presumably present; elytra glabrous, shiny, striae impressed; elytral apex expanded by pair of elongated prong-like tubercles.

Cameroon, Republic of the Congo (new country).

Republic of the Congo, Dimonika, Mayumbe [GIS: -4.46, 12.45] [1, NHMW].

Holotype , male: [Democratic Republic of the] Congo Belge, Kivu, Mulungu, 2.VIII.1952, ex Popowia, KE Schedl, leg. [RMCA, paratype in NHMW].

Figures 57–65. 

Dorsal, lateral, and front views of 57, 60, 63 Ctonoxylon caudatum male holotype 58, 61, 64 Ctonoxylon crenatum male holotype, and 59, 62, 65 Ctonoxylon kivuensis male holotype.

(male). Length 1.6 mm. 2.2× as long as broad; colour brown. Eyes divided, separated by slightly more than the size of upper part; antennal club setose, sutures obscure; male frons slightly impressed, smooth and glabrous in centre, with fine soft setae closer to eyes and vertex; pronotum roughly punctured, with sharp asperities on anterior half, anterior pair of teeth small, located behind front margin; lateral anterior margin of prothorax from middle part to coxa with shallow irregular groove; propleural pit round, deep; elytral striae impressed, punctures large, separated by their diameter or less; vestiture consisting of irregular rows of long, soft bristle-like setae; elytral suture slightly buckled at midlength, apex entire.

Democratic Republic of the Congo.

Only known from the medium altitude (732 m) type locality in the Congo basin, breeding in a Popowia branch (Annonaceae).

Holotype , female: Madagascar, Ankarafantsika NP [GIS: -16.264, 46.828], 200 m alt., 8.5.2015, ex liana, B. Jordal, leg. [ZMUB]. Paratypes: same data as holotype [NHMW, ZMUB].

Anterior teeth on the pronotum quadrifid; lateral anterior margin of prothorax with elongated groove; propleural pit present; scutellar shield detached; elytral suture strongly curved just behind scutellar shield, a little buckled further behind.

Female. Body length 2.6–3.0 mm, 2.1× as long as broad; immature colour pale brown. Frons convex, surface reticulate, vestiture consisting of sparse, short setae. Eyes divided, each part separated by 2/3 the size of upper half. Antennal funiculus 7-segmented; club with two asymmetrically and strongly procurved sutures, suture one more distinctly marked, with a dark partial septum along its front margin. Pronotum broadly asperate on anterior two-thirds, anterior margin with pair of two bifid raised teeth (quadrifid). Anterior lateral margin of prothorax with pointed eye scraper at level of eyes, a deep groove from this point to coxa; a transverse propleural groove located between coxa and lateral costa on pronotum. Scutellar shield detached from elytra. Elytral suture strongly curved immediately behind scutellar shield and slightly buckled at midlength; striae strongly impressed, punctures round, large and deep, spaced by their diameter or less; interstriae raised, vestiture consisting of irregular and partly confused rows of short scale-like setae, with ground vestiture consisting of shorter setae of the same type and density; apex slightly emarginated. Metanepisternum and metaventrite with scant simple setae; last abdominal ventrite with small concavity. Protibiae on anterior face with groove for reception of tarsus as deep as width of tibia.

Male nearly identical to female, except frons impunctate and glabrous in a narrow band from epistoma to upper level of eyes, front teeth along the pronotal margin very slightly behind the position in females, and last abdominal ventrite flat.

Figures 66–74. 

Dorsal, lateral, and front views of 66, 69, 72 Ctonoxylon quadrispinum female holotype 67, 70, 73 Ctonoxylon methneri male, and 68, 71, 74 Ctonoxylon atrum female holotype.

Composed by the Latin prefix quadri- meaning four, and the Latin adjective spinum in its neuter form derived from spina, meaning thorn, referring to the four sharp teeth along the front margin of the pronotum.

Only known from the type locality in Madagascar where broods containing pupae and tenerals, but not parents, were collected from a liana 4 cm in diameter, with thick bark. Egg tunnels were biramous and cut transversely to the grain. Brood sizes ranged from 50–60 (n = 20).

Holotype (‘type’): [Tanzania] Udzungwa-Berge1300–1600 m., 26.XI.1912, Methner, coll. [ZMHB, not found]. Holotype of C. hamatum male: [Kenya] Nairobi [NHMW]. Holotype of C. griseum, female: [Kenya] Brit. O. Africa, Kikuyu [-1.27, 36.68], E. Thomas [NHMW].

Length 2.3–4.2 mm. 2.1–2.3× as long as broad; colour dark brown, dorsal setae variegated. Male frons flat, smooth, impunctate and glabrous within a triangular pattern of short setae near eyes and epistoma; female frons finely granulated with short setae; eye parts separated by almost the size of upper half; anterior lateral margin of prothorax with elongated groove near front of coxa; propleural pit present just above coxa; scutellar shield detached from elytra; elytral suture slightly buckled at midlength; apex emarginated; interstrial vestiture consisting of confused rows of variegated scale-like setae of similar length and colour as the ground vestiture.

Kenya, Tanzania, South Africa.

South Africa, E. Cape Prov., Katberg [GIS: -32.479, 26.673], 01.11.1933, R.E. Turner, leg. [2, NHMUK]; W. Cape province, Knysna, Diepwalle [GIS: -33.957, 23.152], 7.11.2006, ex Olea capensis trunk, B. Jordal, leg; same data except Goudveld, Krisjan Se-Nek [GIS: -33.913, 22.948], 5.11.2006; Goudveld, Woodcutters [GIS: -33.927, 22.976], 4.11.2006; Gouna, Grootdrai [GIS: -33.946, 23.054], 6.11.2006; Nature’s Valley [GIS: -33.965, 23.562], 8.11.2006; Tsitsikamma, Goesa walk [GIS: -33.983, 23.887], 12.11.2006; Tsitsikamma, Platboos walk [GIS: -33.980, 23.910], 14.11.2006 [all in ZMUB]; Kenya, Ngong Forestry [-1.31, 36.73], 12.01.1968, Malaise trap, Krombein & Spangler leg. [1, USNM].

This species is exclusively associated with black ironwood, Olea capensis (Oleaceae) where it is usually present whenever branches and trees are down. Recent field studies in the Knysna forests in the Cape region indicated no particular preference for breeding material size, ranging from 2-cm thick branches to the largest tree trunks of > 60 cm diameter. It breeds in the same host tree as Lanurgus jubatus Jordal, 2021, and Lanurgus xylographus Schedl, 1961, but even though it is found in the same forest localities, C. methneri only co-occurred with these species in the same tree one out of ten collecting events. Brood size was not smaller in the thinnest branches examined and broods with larvae or older stages ranged from 17–48 (Table 5). Very few broods with larvae had a male parent present with the female, and then only at very early larval stage. In the large majority of dissected broods, the male left before all eggs were laid or hatched. The female left her offspring before pupal stage. Egg tunnels were always cut transversely to the wood grain and eggs deposited vertically in deep pits packed with frass.

Some specimens of C. methneri differ from those of C. hamatum by having slightly shorter setae on interstriae 1 and 2 but this appears to be intraspecific variation. The differences in frons and pronotum between the types of C. hamatum and C. methneri on one side, and C. griseum, is due to sexual dimorphism otherwise typical for the genus.

Holotype , male: Nigeria, Idanre [GIS: 7.12, 5.10], 30.9.1964, ex Canthium [NHMUK].

Length 3.4 mm. 2.1–2.2× as long as broad; colour pitch black. Male and female frons slightly impressed and impunctate on lower half, finely granulated above with short scattered setae; eye parts separated by 2/3 the size of upper half; anterior lateral margin of prothorax with elongated groove near procoxa; propleural pit present just above procoxa; pronotum with large and deep irregular punctures; elytral suture buckled at midlength, strial punctures longitudinally elongated, subquadrate; interstriae rough, with irregular punctures and rugosities; elytral apex emarginated; interstrial vestiture of confused rows of short, black, scale-like setae.

Ghana, Cameroon (new country).

Cameroon, Limbe, Ekande [GIS: 4.081, 9.172], 19. Nov. 2007, ex water liana, B. Jordal, leg [1, ZMUB].

This species is rather similar to C. methneri and was synonymised with C. hamatum by Schedl (1970). However, C. atrum is darker, with shorter elytral setae, the strial punctures are narrowly elongated and more separated, and the pronotal punctures are larger. It is genetically clearly separated from C. methneri and instead forms a sister relationship with C. quadrispinum sp. nov. (Fig. 11).

Holotype , male: [Democratic Republic of the] Congo Belge, Yangambi, 9.IX.1952, ex Clitandra staudtii, KE Schedl, leg. [RMCA, paratype in NHMW].

Length 2.6 mm. 2.3× as long as broad; colour pale brown. Male frons reticulate with short fine setae; eye parts separated by the size of upper half; anterior lateral margin of prothorax with obtuse eye scraper, from this point to coxa with elongated groove; propleural pit present; elytral suture slightly buckled at midlength; apex entire, slightly extended and upcurved in lateral view; interstrial vestiture of regular rows of long bristle-like setae.

Figures 75–80. 

Dorsal, lateral, and front views of 75, 77, 79 Ctonoxylon acuminatum female holotype, and 76, 78, 80 Ctonoxylon spathifer male.

One host plant is known, Orthopichonia visciflua (K.Schum. ex Hallier f.) Vonk (Apocynaceae), a thin climbing plant (Schedl 1961).

Superficially similar to C. kivuensis but has shorter setae and the elytral apex in lateral view has a slightly curved extension (Fig. 77).

Syntypes : [Ivory Coast] Cote d’Ivoire, Reserve du Banco [5.39, -4.05] [MNHN, NHMW].

Length 2.6–3.1 mm. 2.3–2.4× as long as broad; colour reddish brown. Eyes divided, separated by the size of upper part; antennal club setose, sutures obscure; male frons roughly punctured, glabrous in middle, with short coarse setae close to the eyes; pronotum with dense subconfluent asperities on anterior two-thirds, a fused pair of teeth just behind front margin; lateral anterior margin of prothorax from middle part to coxa with shallow irregular groove; propleural pit round, deep; elytral striae impressed, punctures large, deep, narrowly separated; vestiture on interstriae consisting of densely confused, short, scale-like setae; elytral suture straight, apex narrowly rounded, entire.

Ivory Coast, Ghana (new country), Tanzania.

Ghana, Samreboi [5.61, -2.55], ex Trichilia rubescens, 10.IX.1962, F.G. Browne, leg. [2, NHMUK].

Known to breed in Olea welwitschii (Oleaceae), Pachylobus deliciosus (Burseraceae), Strombosia postulata (Olacaceae), and Trichilia rubescens (Meliaceae), an unusually broad assemblage of host plants for a true bark beetle.

Holotype : [Tanzania] D.O. Afrika, Amani [ZMHB]. Holotype, C. intermedium: Kamerun, C. Conradt leg. [NHMW].

Length 1.6–1.9 mm. 2.2–2.4× as long as broad; colour brown. Female frons slightly impressed on central lower half, glabrous and impunctate in middle, with short stiff setae around central area; eye parts narrowly separated by half the size of upper eye part; lateral anterior margin of prothorax with obtuse eye scraper, further below near coxa with short elongated groove; propleural pit present above coxa; elytral suture a little buckled at midlength; apex entire; interstrial vestiture consisting of regular rows of narrowly spatulate setae; posterior part of the metaventrite with unusually long, broad setae.

Cameroon, Tanzania.

New record: Tanzania, Morogoro prov. Udzungwa [GIS: -7.85, 36.89], ex liana, 29.6.2010, B. Jordal leg. [ZMUB]. Cameroon, Limbe, Ekande [GIS: 4.081, 9.172], 1100 m alt., ex thin liana, 18.11.2007, A. Breistøl, leg.

One specimen was collected in each of two localities, in countries with type localities for the two synonymised species C. amanicum and C. intermedium. Both specimens were tunnelling in thin lianas, one under bark and one in pith of a stem nodule in which only a short irregular tunnel was made.

Figures 81–89. 

Dorsal, lateral, and front views of 81, 84, 87 Ctonoxylon amanicum female 82, 85, 88 Ctonoxylon uniseriatum female, and 83, 86, 89 Ctonoxylon spinifer female.

The holotype of C. amanicum was supposed to be lost in the museum of Hamburg but was rediscovered in Berlin (ZMHB). The holotype of C. intermedium is identical to C. amanicum in all important characteristics and therefore synonymised.

Holotype : [Namibia] Deutsch S.W. Afrika [NHMW]. Holotype of C. capensis: [South Africa] Umgeberge, Cape Town, 1899 [NHMW].

Length 2.3–2.8 mm. 2.3–2.4× as long as broad; colour dark brown. Male frons slightly inflated, smooth and impunctate with short setae near eyes and epistoma; female frons finely punctured with short erect setae; eye parts separated by the size of upper half; lateral anterior margin of prothorax with short elongated groove near front of procoxa; propleural pit large; scutellar shield detached from elytra; elytral suture a little buckled at midlength; apex entire; punctures on discal interstriae obscure, interstriae 1–7 with uniseriate, spatulate, curved setae, interstriae 8–10 sometimes with variably confused rows of setae, on declivital interstriae 1 and 2 setae partly confused, directed sideways; posterior metaventrite with unusually broad and long setae.

Namibia, South Africa.

South Africa, W. Cape province, 10 km N Hoekwil, Woodville [GIS: -33.933, 22.639], 1.Nov.2006; Knysna, Diepwalle [GIS: -33.957, 23.152], 3.11.2006 and 7.11.2006; Knysna, Goudveld, Krisjan Se-Nek [GIS: -33.913, 22.948], 5.11.2006, all collections ex liana, B. Jordal, leg. [ZMUB].

A common species found exclusively in thin lianas ~ 1 cm in diameter. Females were excavating longitudinal tunnels in the pith and wood of rather fresh material which still exuded latex. Males had left the female either before egg laying or just after the first eggs were laid. Broods were small, with 3–8 eggs per female (Table 5).

A specimen in NHMW marked as the holotype of Cryphalostenus erratium det. Schedl is not published. It is clearly the same species as C. uniseriatum.

https://www.barkbeetles.info/photos_target_species.php?lookUp=7983.

Lectotype , male of C. spinifer: Kamerun, Soppo, 1912, v. Rothkirch leg. [USNM]; paratype, female, same data [NHMW]. Holotype C. setifer: [Tanzania] Amani [lost]; paratype [NHMW].

Length 2.2–2.8 mm. 2.2–2.3× as long as broad; colour brown. Female frons sparsely punctured, lightly granulated with short erect setae; male frons flat, smooth, impunctate and glabrous on central third, with longer setae near eyes and epistoma; eye parts separated by the size of upper half; anterior lateral margin of prothorax with faint eye scraper, below this point with a short elongated groove near front of procoxa; propleural pit present above coxa; scutellar shield detached from elytra; elytral suture a little buckled at midlength; apex entire; interstrial vestiture of mainly regular rows of bristle-like erect setae, interstrial punctures on both disc and declivity dense, distinct; posterior metaventrite with unusually broad and long setae.

Burkino Faso (new country record), Ivory Coast, Cameroon, Democratic Republic of the Congo; Kenya, Tanzania, Madagascar (new country record).

Burkina Faso, Foret de Boulon [10.343, -4.510], 270 m, piege interception (1), piege limeneux (1), 9.7.2006, F. Genier, leg. [CMNC]; Cameroon, Adamoua, 20 km S. Minim [6.49, 12.52], 1200 m alt., 8.3.1982, Flacke & Nagel, leg. [1, ZFMK]; Tanzania, Udzungwa National Park HQ, Mang’ula [GIS: -7.845, 36.880], 200 m alt., ex liana, 9.11.2009 and 29.6.2010, B. Jordal, leg.; Mang’ula [GIS:-7.850, 36.883], ex liana, 14.11.2009, B. Jordal, leg. [ZMUB]; Morogoro, Kimboza Forest Reserve [-7.023, 37.806], S.S. Madoffe, leg. [1, NHMUK]; Madagascar, Reserve speciale de l’Ankarana, 22.9 km SW Anivoran [-12.93, 49.16], B. Fischer, leg. [1, CAS].

Specimens were dissected from the pith of thin lianas, 0.6–1.0 cm diameter, still exuding latex.

The co-types (paratypes) of C. spinifer are identical to those of C. setifer. Because the holotype of C. setifer is lost, and using the principle of first reviser, the name spinifer is given priority. Eggers’ descriptions are very similar and not useful to distinguish specimens. There is some variation within series of various other collections, particularly in the regularity of interstrial rows of setae but this variation follows no predictable pattern. This species is very similar to C. uniseriatum but differs by the erect interstrial setae, particularly on the declivity where setae are not directed sideways as in uniseriatum, by the densely placed interstrial punctures, and in males also by the less inflated upper central frons. Genetic data supported a sister relationship to C. amanicum instead of C. uniseriatum (Fig. 11).

A single specimen is recorded from near the north-west coast of Madagascar. This is not too surprising given the broad Afrotropical distribution of this species.