Anacaena namaqua, Bilton, David T. & Komarek, Albrecht, 2016

Bilton, David T. & Komarek, Albrecht, 2016, A new species of Anacaena Thomson, 1859 from South Africa (Coleoptera: Hydrophilidae), Zootaxa 4139 (4), pp. 593-599 : 594-598

Anacaena namaqua sp. nov.

( Figs 1–3 )

Type locality. South Africa, Northern Cape, Bokkeveld Plateau, Avontuur Reserve , vernal pools on clay, 797 m, 31 17 44.63S // 19 0 1 23.84E ( Fig. 3 B).

Type material. Holotype (male): “ 6/x/2015 South Africa NC// Avontuur Reserve – vernal pools// on clay 797m 31 17 44.63S // 19 0 1 23.84E D T Bilton leg.” (genitalia extracted and mounted on same card) and red holotype label ( AMG) .

Paratypes (47): South Africa: 2 Ƌ, 3 ♀ same data as holotype ( AMG, CDTB) ; 4 Ƌ, 1 ♀ “ 6/x/2015 South Africa NC// Avontuur Reserve – temporary// stream below Fynbos Cottage // 765m 31 16 14.67S // 19 0 2 53.02E D T Bilton leg.” ( NMW, CDTB) ; 2 Ƌ, 1 ♀ “ 6/x/2015 South Africa NC// Avontuur Reserve – pools in drying// temporary stream 795m 31 17 38.92S // 19 0 1 12.03E D T Bilton leg.” ( CDTB, NMW) ; 1 Ƌ, 1 ♀ “ 6/x/2015 South Africa NC// Avontuur Reserve – margins of// Kromvlei 799m 31 18 15.58S // 19 0 0 51.42E D T Bilton leg.” ( NMPC) ; 1 ♀ “ 7/x/2015 South Africa NC// Bokkeveld Oorlogskloof // Reserve – Oorlogskloof River // below// Driefontein 31 30 51.60S 19 06// 48.11E 491 m D T Bilton leg.” ( CDTB) ; 1 Ƌ, 1 ♀ “ 8/x/2015 South Africa NC// Bokkeveld Oorlogskloof Reserve // spring pool at Groot Tuin // 31°26’41.01”S // 19°04’11.13”E, 724m D T Bilton // leg.” ( AMG) ; 2 ♀ “ 18/ix/2010 South Africa NC// Seepage on R27 road @// Vanrhynspass // D T Bilton leg.” ( CDTB) ; 1 Ƌ, 4 ♀ “ 26/ix/2011 South Africa NC// Seepage on R27 road @// Vanrhynspass // D T Bilton leg.” ( CDTB, ISAM) ; 1 Ƌ, 3 ♀ “ 18/ix/2010 South Africa NC// Temporary pool beside R27 road// ca. 2 km E of Vanrhynspass // D T Bilton leg.” ( TMSA) ; 2 Ƌ “ 20/ix/2014 South Africa WC// Gifberg – stream over rocks// in Gifberg Pass // D T Bilton leg.” ( CDTB, SANC) ; 3 Ƌ, 1 ♀ “ 21/ix/2014 South Africa WC// Matsikammaberg stream// 1 km SE of Sewefontein farm// permanent D T Bilton leg.” ( CDTB, OUMNH) ; 3 Ƌ, 2 ♀ “ 21/ix/2014 South Africa WC// Matsikammaberg stream// 1 km NW of Sewefontein farm// D T Bilton leg.” ( AMG) ; 2 Ƌ “ 21/ ix/2014 South Africa WC// Matsikammaberg seepage stream// over rock at head of Elandskloof // D T Bilton leg.” ( ISAM) ; 1 Ƌ, 4 ♀ “ 21/ix/2014 South Africa WC// Matsikammaberg rockpools// on NE edge of plateau// D T Bilton leg.” ( CDTB, TMSA). All with red paratype labels.

Description. Size: Holotype: TL 3.15 mm; EL 2.0 mm; EW 1.55 mm; EI 1.29. Paratypes: Ƌs BL 2.5–3.0 mm; EL 1.5–2.15 mm; EW 1.4–1.5 mm. ♀ s BL 2.5–2.9 mm; EL 1.55–2.25 mm; EW 1.5–1.75 mm.

Colour: Dorsum ( Fig. 1 ) with labrum, clypeus and frons black, lighter margins or preocular patches absent. Pronotum dark brown to almost black, with distinct, broad, yellow lateral margins. Elytra spotted in appearance; ground colour yellowish brown, with a distinct dark brown spot around each irregular puncture, confluent in some places; a larger dark brown patch present in humeral region. Scutellum dark brown to black. Maxillary palpi with palpomeres 2–3 dark yellow; palpomere 4 entirely infuscated. Basal portions of femora dark brown, rest of legs paler. Underside of head largely dark brown to black. Pronotal and abdominal ventrites dark brown to black; pronotal hypomera and elytral epipleurs pale brown.

Head: Clypeus large, with blunt anterolateral angles and slightly concave anterior margin; lateral margin longer than longitudinal diameter of compound eyes. Clypeus and frons shining, without microreticulation and with strong, irregular, distinctly impressed punctures, spaced on average 2–3 puncture-widths apart. Frontoclypeal suture not visible. Compound eyes large, very slightly protruding, not emarginate anteriorly; dorsal and ventral portion equally sized. Antennae with eight antennomeres. Maxillary palpi moderately slender, half as long as maximum width of clypeus; palpomere 2 distinctly inflated. Palpomeres 2:3:4 = 0.12 mm: 0.09 mm: 0.16 mm. Labial palpi moderately slender, elongate, slightly longer than lateral margin of mentum.

Pronotum: Transverse, highly arched, broadest at posterior angles. Anterior and posterior angles broadly rounded; anterior angles protuding. Anterior margin arcuate over central 0.5; posterior margin arcuate. All margins with narrow bead. Lateral margins without evident setae. Surface shining, without microreticulation; punctures as on head.

Elytra: Elongate oval, broadest behind middle; subparallel over anterior 0.7 then evenly rounded to apex; weakly emarginate around suture. Lateral margins without setae. Humeral region without evident callosity. Sutural stria present on posterior 2/3 of elytra. Upper surface shining, without microreticulation. Punctures as on head and pronotum; series absent.

Venter: Mentum flat with convex lateral margins; distinctly depressed anteriorly, anterior margin slightly emarginated. Surface shining, without microreticulation and with sparse setiferous punctures. Prosternum slightly tectiform, without median carina. Mesoventrite flat, without evident process. Abdominal ventrites entirely pubescent; ventrite 5 not emarginate apically.

Legs: Procoxae without spine-like setae. Profemora ( Fig. 2 A) pubescent on proximal 2/3 of ventral face with slightly oblique hairline; mesofemora ( Fig. 2 A) pubescent on proximal 2/3 of ventral face with straight hairline; metafemoral pubescence ( Fig. 2 A) reduced to a narrow strip over mesal half of anterior margin and on proximal portion, adjacent to metatrochanter. Metatibia with strong spines on lateral face; distal spurs slender, longer mesal spur reaching midway along tarsomere 2 ( Fig. 1 ). Metatarsus slightly shorter than metatibia.

Aedeagus: Phallobase longer than parameres, longer than wide, evenly converging to the distinct, large, knoblike manubrium. Ventral face of phallobase largely unpigmented, borderline between unpigmented and pigmented part of ventral face reaching manubrium. Parameres with sigmoidal mesal margins and evenly rounded lateral margins, slightly inflated at their blunt apices. Ventral bases of parameres fused. Dorsal bases curved, not distinctly reaching into phallobase. Median lobe wide, short, widening from the base to approximately halfway along its length, then narrowing to relatively wide, blunt apex. Apex of median lobe reaching apex of parameres or slightly shorter; corona in apical position. Basal apophyses as long as main piece of median lobe, with distinct extension into phallobase, pointing mesad. Base of median lobe distinctly connected with parameres by a very blunt tooth ( Fig. 2 B). Aedeagal length 0.44–0.45 mm.

Female: Not significantly different from males.

Variation: Some variation in elytral colour pattern, some paratypes either paler (sometimes due to tenerality) or darker than the holotype, but mottling always evident.

Etymology. Named in reference to the Namaqua District of the Northern Cape, where many of the known localities are situated. The name is a noun in apposition.

Distribution and ecology. A. namaqua sp. nov. is known to date from a number of localities, comprising both running and standing waters (e.g. Fig. 3 ), all of which are on the Bokkeveld Plateau close to Nieuwoudtville, or on the nearby Gifberg/Matsikammaberg massif. These mountains form part of the southern and southeastern borders of Namaqualand, being at the point where the fynbos biome meets the succulent karoo ( Cowling & Pearce 1999; van Wyk & Smith 2001; Manning & Goldblatt 2012). The Bokkeveld has reliable winter rains and is much wetter than surrounding areas of Namaqualand. As a consequence the region is home to a diverse flora, including many endemic geophytes (van Wyk & Smith 2001), and supports a range of largely temporary aquatic habitats. The Gifberg/Matsikammaberg forms a southwesterly outlier from this plateau, and is a striking inselberg, reaching just over 1,000 m in altitude, with 700 m high sandstone cliffs towering over the dry Knersvlakte. It represents a mesic island in an otherwise semi-arid landscape, annual rainfall being up to 550 mm, contrasting with as little as 50 mm per year on the plains below. The Matsikammaberg also supports a rich flora, 10% of which is regionally, and 4% locally endemic ( Helme 2004).

Differential diagnosis and key to South African Anacaena . The new species is most similar structurally to A. capensis Hebauer, 1999 , A. glabriventris Komarek, 2004 , A. reducta Komarek, 2004 and A. tenella Hebauer, 1999 , sharing the following features with these South African species: eight antennomeres, no preocular patches on clypeus, flat mesoventrite, colouration of the pronotum (dark brown to black with broad yellow lateral margins), absence of serial elytral punctures, reduced metafemoral pubescence and a similar aedeagus. Anacaena namaqua sp. nov. can be distinguished from A. reducta and A. tenella on its larger body size (2.5–3.15 vs. <2.5 mm), from A. capensis on its distinctly impressed dorsal punctures and from A. glabiventris on the entirely pubescent abdominal ventrites and short, inflated parameres. The aedeagus is most similar to that of A. reducta . In addition the new species differs from all Afrotropical Anacaena in having distinctly speckled elytra, a colour pattern present in all specimens examined to date. The new species can be distinguished from other South African Anacaena as follows:

1 Habitus strongly convex; antennae with nine antennomeres; elytra with ten series of punctures in addition to irregular puncta- tion on intervals (species originally described as Grodum Hansen, 1999 )......................................... 2

- Habitus moderately convex; antennae with eight antennomeres; elytra with irregular punctation; serial punctures absent... 3

2 Interval punctures very fine, less than half diameter of serial punctures; hind wings rudimentary..... striata ( Hansen, 1999)

- Interval punctures moderately coarse, about half diameter of serial punctures; hind wings well developed................................................................................................ endroedyi ( Hansen, 1999)

3 Elytra light brown speckled with darker brown spots and patches.................................. namaqua sp. nov.

- Elytra unicolorous dark brown or black, lacking obvious mottling.............................................. 4

4 Total length greater than 2.5 mm; pronotal punctures moderately coarse or coarse................................... 5

- Total length less than 2.5 mm; pronotal punctures relatively fine................................................ 6

5 Pronotum and elytra black; elytral punctures coarse, shallow; abdominal ventrites entirely pubescent...................................................................................................... capensis Hebauer, 1999

- Pronotum and elytra dark brown; elytral punctures moderately coarse, rather deep; abdominal ventrites partly glabrous................................................................................... glabriventris Komarek, 2004

6 Punctures on pronotum and elytra coarser; pronotum and elytra typically similar shades of brown; aedeagus characteristic...................................................................................... reducta Komarek, 2004

- Punctures on pronotum and elytra finer; pronotum typically black, darker than the browner elytra; aedeagus characteristic....................................................................................... tenella Hebauer, 1999

Figures

FIGURE 1. Dorsal habitus of Anacaena namaqua sp. nov., holotype. Scale bar = 1 mm.

FIGURE 2. Anacaena namaqua sp. nov. A) venter of paratype; B) aedeagus of paratype. Scale bars = 1 mm & 0.2 mm, respectively.

FIGURE 3. Anacaena namaqua sp. nov. localities. A) South Africa, Northern Cape, Avontuur Reserve – margins of Kromvlei, 799 m; B) South Africa, Northern Cape, Avontuur Reserve – vernal pools on clay, 797 m. Photos D T Bilton.