Tijdschrift voor Entomologie 156 (2013) 11–19 brill.com/tve

Carinomezium (Coleoptera: Ptinidae): A new genus from the Namaqualand region of South Africa Matthew V. Wood & T. Keith Philips

A unique new genus and species of spider beetle from Namaqualand from the Succulent Karoo Biodiversity Hotspot in South Africa is described. The genus Carinomezium gen. n. is characterized by pronounced longitudinal carinae on the elytra, four large rounded setal tufts that cover the pronotum, and the very small body size. The single representative species, Carinomezium namaquaensis sp. n. is diagnosed, described, and illustrated. The phylogenetic placement of this taxon is also discussed. Keywords: Carinomezium, Coleoptera: Ptinidae, new genus, Namaqualand, South Africa, Bostrichoidea, diversity. Matthew V. Wood, Systematics and Evolution Laboratory, Department of Biology, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101–3576. [email protected] T. Keith Philips*, Systematics and Evolution Laboratory, Department of Biology, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101–3576. [email protected]

Introduction lations with restricted distributions; hence the fauna About 25 percent of the described genera of the is most likely still quite poorly known. family Ptinidae, sensu stricto (i.e., including only the South Africa has once again revealed a unique spider beetles and not the anobiids) are found in new taxon from Namaqualand, a western region of South Africa. This currently includes 13 endemic this country that is part of a well-known biodiversity genera, four additional widespread genera, and 47 hotspot containing many endemic taxa. We take this documented species (see Irish 1996a, 1996b; Philips opportunity to document this species making the & Foster 2004; Borowski 2006a, 2006b, 2009; Bell name available for completed but not yet published & Philips 2008; Akotsen-Mensah & Philips 2009; phylogenetic studies. Smiley & Philips 2011; Trimboli & Philips 2011). Spider beetles arguably are one of the most mor- phologically diverse coleopteran families, but they Carinomezium Wood&Philips,gen.n. are a relatively small group including only about 600 Type species: by monotypy: Carinomezium na- species. The recognition of so many genera (and each maquaensis sp. n. often with one or few species) in South Africa in- dicates that there is an amazing degree of morpho- Diagnosis logical diversity in this region. Additionally there is This genus can be recognized by the distinctive raised probably still a lack of biodiversity knowledge as well, carinae on the elytra as well as the inflated setal perhaps in part due to their small body size, incon- covering on the pronotum consisting of two large spicuous coloration, and often relatively small popu- rounded tufts on either side of midline and two

Tijdschrift voor Entomologie 156: 11–19, Figs 1–16. [ISSN 0040-7496]. brill.com/tve © Nederlandse Entomologische Vereniging. Published by Koninklijke Brill NV, Leiden. Published 15 July 2013. DOI 10.1163/22119434-00002019

Downloaded from Brill.com10/07/2021 09:57:39AM * Corresponding author via free access 12 Tijdschrift voor Entomologie, volume 156, 2013 smaller rounded lateral tufts. Additionally, this taxon Etymology is the smallest known in southern Africa with an Derived from the Latin “carin” (meaning keel), refer- average size of only 1.1 mm. ring to longitudinal ridges on the elytra; this is com- bined with the ptinid genus name Mezium,oneof Description the other genera that has setal tufts on the prono- Body. very small, average length 1.1 mm, ovoid, tum. convex. Head. Eyes not visible dorsally, small, ovoid, om- Carinomezium namaquaensis Wood & matidial surface facing upwards; vertex very slightly Philips, sp. n. convex, antennal fossae distinct, not continuous be- Figs 1–16 low eye; antennae short in length, distinctly shorter Type material. Holotype: South Africa; Namaqua- than body length, antennomeres stout, 11 anten- land, Soutpan dunes, 31.15S–17.52E/1.8.1989; E– nomeres, second antennomere inserted off center of Y: 2623, litter under bushes, Endrödy & Klimaszew scape near lateral edge; interantennal space between (Deposited in the Ditsong National Museum of antennal insertions narrow, thin carina projecting be- Natural History (formerly known as the Transvaal tween antennal fossae, peaking at middle; clypeus tri- ≈ Museum (TMSA))). – Paratypes: (37) with same angular, width 2/3 width of head below eyes, ante- data; (2) S. Afr.; W. Cape Prov., Lambertsbai coast, rior edge of labrum small and slightly emarginated in 32.07S–18.17E/30.7.1989; E–Y: 2620, litter in middle, mandibular apex is acutely pointed, mentum hummocks, Endrödy & Klimaszew; (1) S. Afr., SW is triangular, with cavity at middle. Cape, Papendorp dunes, 31.38S–18.12E/22.8.1981; Pronotum. Two large swollen setal convexities E–Y: 1830, groundtraps. 64 days, leg. Endrödy- on either side of median line and smaller similar Younga/groundtrap with feces bait; (1) S. Afr., SW convexity on lateral margin formed from densely Cape, Papendorp dunes, 31.38S–18.12E/22.8.1981; packed setae, cuticle surface not visible. E–Y: 1828, groundtraps, 64 days, leg. Endrödy- Elytra. Convex, distinct carinae running length of Younga/groundtrap with feces bait; (1) S. Afr., each elytron dorsally, surface with rows of distinct SW Cape, Nortier farm, 32.03S–18.19E/25.8.1981; large rounded punctures. × E–Y: 1845, groundtraps, leg. Endrödy-Younga/ Thorax. Prosternal process narrow, about 3 as groundtrap with meat bait [NOTE: correct longi- long as wide, approximately parallel sided, apex tude for Nortier Farm is 18.32E]; (1) S. Afr., Cape- slightly expanded, not quite exceeding the pro- Karoo, Zwartskraal farm, 33.10S–22.32E/5.9.1979; coxae posteriorly, slightly extending into mesoster- E–Y: 1640, groundtraps, 50 days, leg. R. Oost- num; mesosternum slightly longer than wide, 2/3 huizen/groundtrap with feces bait (Paratypes in Dit- the length of metasternum at middle, mesoster- song National Museum, National Collection in Pre- nal process between mesocoxae anteriorly adjacent toria (SANC), South African Museum (SAMC), and to procoxae with ventral projections on either side collection of the second author (TKPC)). of apex of prosternal process; posterior margin One should be aware that the last single specimen of metasternum broadly emarginated; mesosternal- record is almost certainly the result of a mislabeled mesepisternal suture absent. specimen and has been omitted from the distribution Abdominal Ventrites. Ventrites very narrow, ap- map (Fig. 16). proximately 1/4 total width of body, first three su- tures visible, 4th less apparent (viewed in glycerin), first abdominal ventrite longest at middle, narrowed Diagnosis This species can be recognized by the three distinc- laterally, 2nd–4th slightly shorter than 1st and sub- nd th tive strongly raised carinae on the elytra and the equal, lengths at middle of 2 –4 ventrites approx- shape of the inflated setal covering on the pronotum th imately equal with some variance laterally, 5 nearly consisting of two large tufts on either side of midline as long as all others combined. and two smaller lateral tufts. With an average size Legs. Short, femora and tibia expanded toward of about 1.1 mm, this spider beetle is the smallest apex, tibiae proportionally similar in length to known in southern Africa. their respective femora; tarsomeres short, 5th the longest; procoxae approximately rounded, meso- × Description coxae more so, nearly 2 diameter of procoxae, Color tan on head and pronotum, dark reddish metacoxae approximately subtriangular; trochanters brown on elytra; body oval, very small, stout, and slightly rounded, protrochanter small, mesotrochan- convex. Length 0.99–1.31 (1.14 ± 0.08) mm (n = ter slightly larger, metatrochanter distinctly larger 46). than either.

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Figs 1–4. Carinomezium namaquaensis, adult. – 1, Dorsal habitus; 2, Ventral view; 3, Lateral view; 4, Frontal view.

Head dorsally uniformly covered in light brown, Elytral surface lacking setae; three prominent cari- elongate, ovoid shaped scales, vertex anteriorly and nae dorsally extending entire length of each elytron, antennal fossae glabrous; striae visible between an- smaller 4th carina laterally, indistinct small carina terior edge of antennal fossae and vertex (when im- along sutural margin; large punctures in two rows mersed in glycerin), distinctly lighter in color; anten- between each carina, and extending slightly onto nae densely setose, second and apical antennomere ridges; punctures relatively uniform in size, broadly about 2× as long as wide, remainder subequal. gradually concave, shallow in depth, at middle each Pronotum with four setal convexities, apices of puncture separated longitudinally by no more than these rounded, outer covering appearing porous and 1/4 diameter of puncture, rows separated by similar sponge like, stout spike-like setae protruding from distance. some pores, convexities on either side of midline pro- Pro-, meso-, metasternum, and abdominal ven- jecting at ≈30° angle, convexities on lateral mar- trites covered with setal scales, similar to those on gins projecting at ≈45°, medial convexities approxi- head, largely obscuring surface. Metasternum with mately twice the size of lateral convexities.

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Figs 5–7. Carinomezium namaquaensis, SEM head views. – 5, Head and antennae; 6, Close up of head; 7, base of antenna, insertion point. approximately six large rounded shallow noncon- Biology tiguous punctures. Carinomezium namaquaensis is most likely a dung Femora and tibiae narrow; femora increasing in and perhaps detritus feeder, like most if not all of the girth from base to apex, more abruptly near mid- species of spider beetles found in this region. Most dle; tibia gradually increasing in girth throughout; of the specimens were collected from litter under 5th tarsomere moderately long, about twice length bushes, areas that rodents typically frequent. Hence of penultimate, 1st–4th distinctly shorter and sub- it is likely that the detritus contains numerous dung equal. pellets that are used as food. With the small size Sexual dimorphism is not apparent externally. of this species, it is likely that even relatively tiny dung pellets could be consumed by larvae feeding internally. Several of the specimens were collected Etymology with dung or meat bait, another indication of the The specific name “namaquaensis” refers to the re- typical generalist detritivore feeding habits that are gion of the Succulent Karoo Biodiversity Hotspot in most likely characteristic for this species. western South Africa this species is known from and where it is likely endemic.

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Figs 8–11. Carinomezium namaquaensis, ventral surface structures and genitalia. – 8, Abdominal ventrites; 9, Meso- and metaventrites; 10, Mentum; 11, Male genitalia, ventral view.

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Figs 12–15. Carinomezium namaquaensis, mouthparts. – 12, Labium, slightly rotated and left palpomere missing; 13, Maxilla; 14, Mandible; 15, Labrum.

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Fig. 16. Distribution of Carinomezium namaquaensis in the western part of South Africa.

Discussion other known in the world. It also has a rich endemic Most genera and species of spider beetles in south- fauna in many invertebrate groups such as arachnids, ern Africa appear to be habitat specific and narrowly hopliniine scarab beetles, and aculeate wasps (Ver- endemic as is Carinomezium namaquaensis (Fig. 16). non 1999). Adding to the relative uniqueness of this This new species is known only from a small part region is that it is characterized by a winter rainfall of southern Namaqualand in western South Africa, regime. aregionthatispartoftheSucculentKarooBio- Unfortunately, the degree of protection in the diversity Hotspot (Anonymous 2012). It is one of Succulent Karoo hotspot is extremely poor with only only two (of the approximately 35 defined) entirely 3.5% in category I reserves (Driver et al. 2003), and arid ecosystems to be given hotspot status. The flora the Richtersfeld National Park (category II reserve and fauna is incredibly diverse and with high en- [other land uses allowed]) is heavily overgrazed in demicity (Driver et al. 2003). This includes 6356 numerous localities from domestic livestock (Davis plant species (168 families, 1002 genera), many of et al. 1994, pers. obs.). Indeed, over 90% of the which, as the region’s name implies, are succulents region is used for grazing, and activities such as with over 1700 species. The dominance of the suc- ostrich farming and mining continue to increase culent flora makes this desert landscape unlike any (Desmet & Cowling 2004).

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The diversity of spider beetles reflects two global where in the relationship mix of these three genera evolutionary trends for this group. First, there ap- is likely Costatomezium, a fourth genus not included pears to be high diversity at both the generic and in this study. Based on a phylogeny from Bellés specific levels throughout the drier tropical and sub- (1985), Mezium Curtis, Damarus Péringuey, Gib- tropical regions of the world. Second, flightlessness bium Scopoli, and Sulcatogibbium Bellés may also be frequently evolves, most likely as an adaptation to part of this clade. More recent evidence is from an- reduce water loss (Philips 2000). Fusing wing covers other morphological based phylogeny (G. Mynhardt, (elytra) and controlling gas exchange within a sealed unpublished) that shows Carinomezium near the base elytral chamber appears to be an efficient way of pre- of a clade that includes all genera previously men- venting water loss during respiration in xeric regions. tioned as well as Meziomorphum Pic, Cryptopenicu- These two trends are related in that it appears be- lus Philips, and another undescribed taxon that likely coming flightless increases the speciation rate in spi- deserves generic status (and does not appear to create der beetles by reducing vagility and leading to more non-monophyly in any existing genus). It is notable isolated populations that then evolve as separate lin- that all of these lineages except for one are endemic eages leading to the evolution of novel genera and to southern Africa. species such as in the case of C. namaquaensis. Three of the most biologically important localities in the world are located in South Africa – the biodi- versity hotspots of the Succulent Karoo containing Systematic affinities C. namaquaensis, the Cape Floral Kingdom, and the The unique elytral morphology with distinctly pro- Maputaland-Pondoland-Albany region. The unique- nounced carinae seen in C. namaquaensis is not ness of the first region is further supported by the known in any other spider beetle, hence relation- documentation of this new genus and species, and ships are not immediately obvious. But the most which now brings the endemic genera total in South likely lineages that share recent common ancestry Africa to 14. We have little doubt that many more with this new genus and species are perhaps other taxa are left to discover and document in this biolog- southern African (or Gondwana) taxa that appear ically fascinating region. morphologically similar in at least some character- istics. Carinomezium resembles Lepimedozium Bellés as both have abdominal ventrites greatly reduced in Acknowledgements width compared to total body width. But in the over- We are very grateful to Ruth Müller and Charles Bel- all shape and rounded pronotal surfaces composed lamy for providing us the opportunity to study spec- of a distinct thick and tan coloured setal covering, imens from the Ditsong National Museum of Natu- this new genus appears closer to Stethomezium Hin- ral History and in particular the support given while ton. Stethomezium and Lepimedozium may be sister the second author was on a postdoctoral fellowship taxa (with Carinomezium as sister to that clade), as at the University of Pretoria and a sabbatical while at species in these two genera both have similar elytral Western Kentucky University (WKU). The authors setation (lacking in Carinomezium) and overall head gratefully acknowledge the support of the Center for morphology, including both a comparably shaped Biodiversity Studies at WKU and a NSF Biological clypeus and interantennal carina. Based on similar Surveys and Inventories grant (DEB 0430132) that or close distributions, perhaps the most likely can- has helped to support studies on spider beetles. We didate for the sister clade is the lineage composed thank one anonymous reviewers for their useful com- of species of Stethomezium (Irish 1996a). Species are ments. widespread in southern Africa but one species, S. no- tiale (Peringuey), is found predominantly in coastal References areas of western South Africa and overlaps with C. namaquaensis. Lepimedozium, found in the central Akotsen-Mensah, C. & T. K. Philips, 2009. Description and eastern part of South Africa north to Kenya, of a new genus and eight species of spider beetles (Coleoptera: Ptinidae) from South Africa. – Zootaxa seems to be the less likely sister group candidate. 2160: 51–67. Morphological evidence of close relationships of Anonymous, 2012. Biodiversity Hotspots, Conservation lineages previously mentioned can be misleading due International, Succulent Karoo. [online]. Avail- to convergence. But evidence of close relationship able from http://www.biodiversityhotspots.org/xp/ of these three genera is seen in several phylogenies Hotspots/karoo/Pages/default.aspx [accessed 5 March based on a large set of morphological characters. In 2012]. one, Carinomezium appears as sister to Stethomez- Bell, K. L. & T. K. Philips, 2008. A revision of the ium and they in turn are sister to Lepimedozium South African myrmecophile Diplocotidus (Coleoptera: (Akotsen-Mensah & Philips, unpublished). Some- Ptinidae). – African Entomology 16: 33–40.

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Bellés, X., 1985. Sistemática, filogenia y biogeografía de la Conservation Unit, Botanical Society of South Africa, subfamilia Gibbiinae (Coleoptera: Ptinidae). – Treballs Cape Town. del Museum de Zoologia 3: 1–94. Irish, J., 1996a. The southern African genera Stethomezium Borowski, J., 2006a. Hieleptinus uhligi – a new genus and Hinton, Meziomorphum Pic and Lepidomezium Bellés species from South Africa (Coleoptera, Ptinidae). – (Coleoptera: Ptinidae, Gibbiinae). – Navorsinge van die Annals of Warsaw Agricultural University, Forestry and Nasionale Museum 12: 317–334. Wood Technology 60: 3–6. Irish, J., 1996b. The species of Damarus Péringuey Borowski, J., 2006b. Scaleptinus – a new genus for Ptinus (Ptinidae: Coleoptera). – African Entomology 4: 125– sericans (Peringuey 1888) and Ptinus squamulosus (Pic 129. 1908) and description of two new species belonging Philips, T.K., 2000. Phylogenetic analysis of the New to the new genus (Coleoptera, Ptinidae). – Annals of World Ptininae (Coleoptera: Bostrichoidea). – Syste- Warsaw Agricultural University, Forestry and Wood matic Entomology 25: 235–262. Technology 60: 17–23. Philips, T.K. & D. Foster, 2004. Cryptopeniculus nigrosetus Borowski, J., 2009. The spider beetles of the continental n.g., n.sp. (Coleoptera: Ptinidae) from the Namaqua- Africa (Coleoptera: Ptinidae). Part III. Eutaphroptinus land region of South Africa. – Zootaxa 577: 1–11. gen. n. from South Africa with description of two new Smiley, M.E. & T.K. Philips, 2011. Review of the South species belonging to the new genus. – Studies and re- African spider beetle genus, Pseudomezium Pic, 1897 ports of the District Museum Prague-East. Taxonomi- (Coleoptera: Ptinidae: Ptininae). – African Entomology cal Series 5: 11–16. 19: 572–596. Davis, S.D., V.H. Heywood & A.C. Hamilton (eds), 1994. Trimboli, S.R. & T.K. Philips, 2011. Description of a new Centers of plant diversity. A guide and strategy for species of Meziomorphum Pic (Coleoptera: Ptinidae) their conservation, Vol. 1: Europe, Africa, South West from the Western Cape region of South Africa. – The Asia, and the Middle East. – The World Wildlife Fund Coleopterists Bulletin 65: 109–114. (WWF) and the IUCN – The World Conservation Vernon, C.J., 1999. Biogeography, endemism, and diver- Union. IUCN Publications Unit, Cambridge. sity of animals in the Karoo. – In: W.R.J. Dean & Desmet, P.G. & R.M. Cowling, 2004. Succulent Karoo. S.J. Milton (eds), The Karoo: Ecological Patterns and – In: Hotspots Revisited. Cemex Books on Nature, Processes: 57–86. Cambridge University Press, Cam- Conservation Book Series. bridge. Driver, A., P.G. Desmet, M. Rouget, R.M. Cowling & K.E. Maze, 2003. Succulent Karoo Ecosystem Plan Received: August 26, 2012 Biodiversity Component Technical Report. – Cape Accepted: February 20, 2013

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