Canthyporus namaqualacrimus, Bilton, David T., 2015

Bilton, David T., 2015, A review of the Canthyporus exilis group, with the description of two new species (Coleoptera: Dytiscidae), Zootaxa 3957 (4), pp. 441-454 : 442-445

publication ID	https://doi.org/ 10.11646/zootaxa.3957.4.5
publication LSID	lsid:zoobank.org:pub:F2F3527C-4F96-4AA6-ACCE-C1342DC7BED7
DOI	https://doi.org/10.5281/zenodo.6094438
persistent identifier	https://treatment.plazi.org/id/03BF3962-FFE9-FF94-7187-3C3E7839F8BD
treatment provided by	Plazi
scientific name	Canthyporus namaqualacrimus
status	sp. nov.

Treatment

Canthyporus namaqualacrimus sp. nov.

( Figs 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 & 6 View FIGURE 6 )

Type locality. South Africa, Northern Cape Province, Kamiesberg, Johannes se Berg, seepages over sloping rockface below summit, 30°19'54.82''S 18°06'45.26''E, 1,470 m. ( Fig. 6 View FIGURE 6 A).

Type material. Holotype (male): “ 17/ix/2014 South Africa NC// Kamiesberg—seepages over// rock below summit of Johannes// se Berg ca. 1,470 m D T Bilton leg.” (genitalia extracted and mounted in DMHF on same card) with red printed holotype label “ Holotype // Canthyporus namaqualarcimus sp. nov. // Bilton” ( ISAM).

Paratypes: 6♂, 6♀ same data as holotype ( CDTB, DMSA, ISAM, NMW, SANC, OUMNH). All with red printed paratype labels “ Paratype // Canthyporus namaqualarcimus sp. nov. // Bilton”.

Description. Size: Holotype: body length (to elytral apices) 3.05 mm; maximum width (elytra) 1.65 mm; elytral length 2.5 mm. Same values for paratypes: 3.05–3.15 mm, 1.55–1.65 mm and 2.45–2.60 mm respectively.

Colour ( Fig. 1 View FIGURE 1 D): Dorsal surface predominantly yellowish brown to ferrugineous. Head pale ferrugineous, with anterior margin of clypeus dark ferrugineous. Dark brown patches running along inner margins of compound eyes, separated from eyes by narrow pale ferrugineous area. Dark patches narrow anteriorly, gradually broadening towards posterior margin of head. Pronotum yellowish-pale ferrugineous; narrowly dark brown along anterior and posterior margins. Disc with diffuse dark red-brown central longitudinal marking, and arcuate dark band laterally in posterior 1/2, tracing approximate position of prothoracic gland reservoir. Elytra yellowish to greenish brown, with irregular light brown spots and markings. Antennae with segment 1, proximal 1/2 of segment 2, segments 3–4 and base of segments 5–11 pale yellow; remainder dark brown to black. Maxillary palpi yellowish, apical segment broadly infuscated. Legs yellow to ferrugineous, with segmental junctions and apical segments of pro- and mesotarsi infuscated. Venter black; prementum ferrugineous, pronotal hypomera and outer section of elytral epipleura yellowish.

Head: Broad, with large eyes. Anterior margin of clypeus weakly rounded. Shallow, arcuate frontal depressions present, opening anterolaterally towards anterior border of clypeus. Surface shining, with fine isodiametric microreticulation. Punctation extremely fine, almost imperceptible, clearest towards posterior margin. Antennal segments stout; segments 3–4 narrower than remainder.

Pronotum: Rectangular, strongly transverse, broadest at posterior angles. Anterior margin weakly arcuate; posterior margin bisinuate around centre. Lateral margins narrowly bordered; converging towards anterior angles, almost straight in posterior 1/2; more rounded in anterior 1/2. Anterior angles acute; posterior angles obtusely rounded. Surface shining, with fine isodiametric microreticulation; very finely punctate, punctures most clearly visible on disc. Irregular transverse row of coarse punctures along anterior margin, each bearing a fine decumbent seta.

Elytra: Elongate ovate, broadest at middle. Subparallel in anterior 1/2, gradually tapering towards apex in posterior 1/2. Surface shining, with fine isodiametric microreticulation and very fine, sparse punctation. Sutural puncture row effectively obsolete, traces of depressions anteriorly. Discal, dorsolateral and lateral coarse puncture rows distinct and regular, each puncture bearing a short decumbent seta. Punctures in discal row denser than those in dorsolateral and lateral rows, spaced approximately 2–4 puncture widths apart; punctures in outer rows spaced more than 5 puncture widths apart.

Venter: Mentum and prementum smooth and shining, lacking microreticulation and with sparse, stout, golden setae. Mentum broadly concave, produced laterally to form a dome around centre. Gula shining, lacking microreticulation. Genae shining, with shallow microreticulation; meshes relatively large and isodiametric to slightly transverse in posterior 2/3, smaller and more transverse in anterior 1/3 below posterior margin of compound eye. Pronotal hypomeron broad, shining, with shallow, slightly elongate microreticulation.

Proepisternum smooth and shining, without microreticulation. Prosternum rugulose and densely setose. Prosternum and neck of prosternal process forming a more or less continuous angle of approximately 45° with venter; neck of process with stout, erect setae. Prosternal process elongate, spindle-shaped, laterally beaded in anterior 1/2. Medial surface very weakly convex, almost flat, apex located in impression in anterior metaventral process; surface shining, with sparse, medium, shallow punctures, each bearing a recumbent seta. Metaventrite and metepisternum shining, with transverse to isodiametric microreticulation. Metaventrite wrinkled laterally. Elytral epipleura shining, with shallow, isodiametric microreticulation in outer 2/3, with a shining inner ridge lacking microreticulation. Epipleurs as broad as pronotal hypomeron at shoulders, narrowing evenly to level of metacoxae and continuing as narrow ridge to apex. Metacoxae shining, with isodiametric to elongate microreticulation. Metacoxal lines strong, arcuate, diverging anteriorly; punctate, punctures bearing long, decumbent setae. Metacoxal fissure narrow but distinct. Metacoxal process free, lobes broadly rounded and diverging laterally. Abdominal ventrites shining, microreticulate. Ventrites 1–3 fused, junctions weakly visible, but segments distinct due to changes in microreticulation. Microreticulation more or less isodiametric on ventrite 1, elongate on ventrite 2 and transverse on ventrite 3. Ventrites 4–6 with increasingly isodiametric microreticulation; meshes weakly transverse on ventrite 4, weakly transverse to isodiametric on ventrite 6 and distinctly isodiametric on ventrite 6. Ventrites 2–4 with a central tuft of long, stout, recumbent setae, and a transverse row of 4–6 additional smaller recumbent setae running along centre.

Legs: Basal three segments of pro- and mesotarsi somewhat expanded, with suction setae ventrally. Apical segment of mesotarsi elongated, longer than apical segment of protarsi. Tarsal claws elongate, arcuate, simple; equally elongated on pro- and mesotarsi.

Aedeagus: Median lobe characteristically shaped ( Fig. 2 View FIGURE 2 D); relatively large and heavily sclerotized, with a truncately rounded apex and median constriction in ventral view. Parameres ( Fig. 2 View FIGURE 2 D) broad, with distinct apical tuft of setae.

Females: As males except for more strongly impressed microreticulation on dorsum and venter, stronger and slightly coarser punctation on dorsum, particularly on head and pronotum, as well as narrower pro- and mesotarsi, which lack suction setae. Apical segment of mesotarsi shorter than in males, equivalent length to apical segment of protarsi. Pro- and mesotarsal claws shorter than in males. Spermathecal tract heavily sclerotized, spermatheca robust, curved, relatively elongate ( Fig. 3 View FIGURE 3 C).

Variation: Paratypes vary slightly in size (see above) and the development of the dorsal pattern, some specimens being somewhat darker or lighter than the holotype.

Differential diagnosis. The new species is a member of the exilis group of Canthyporus ( Biström & Nilsson 2006) , characterised by the relatively flattened dorsum, distinctly 5 segmented mesotarsi, dense apical hair tuft on the parameres and a relatively simple median lobe, lacking a dorsal projection. At 3.05–3.15 mm, C. namaqualacrimus sp. nov. is the largest member of the group described to date. In size, colouration and aedeagal morphology the new species is closest to C. aenigmaticus , from which it can be distinguished by its larger size (3.05–3.15 versus 2.6–2.7 mm), more elongate body shape, finer dorsal punctation, absence of a distinct anterior depression on the head, as well as details of the aedeagus and spermathecal tract ( Figs. 2 View FIGURE 2 & 3 View FIGURE 3 ).

Distribution and ecology. Known only from the type locality, madicolous seepages at the head of a small stream draining the granite summit dome of Johannes se Berg, close to Leliefontein in the high Kamiesberg of the Northern Cape Province. The highest Kamiesberg summits, including Johannes se Berg, experience much higher rainfall than most of Namaqualand, and support outliers of fynbos vegetation, much of which is endemic to the range ( Helme & Desmet 2006). The new species seems likely to be found in similar habitats elsewhere in the Kamiesberg, such as on the summit dome of the Rooiberg. At Johannes se Berg this species occurred together with C. pallidus sp. nov., Anacaena capensis Komarek, 2004 , Crenitis zimmermanni Knisch, 1924 , Laccobius praecipuus Kuwert, 1890 , Hydraena duodecimata Perkins, 2014 , Parasthetops curidius Perkins & Balfour- Browne, 2008, P. striatus Perkins, 2008 and Pneuminion velamen Perkins, 1997 .

Etymology. From Namaqualand, the region in which the Kamiesberg range is situated, and the Latin lacrima (= tears), in reference to the habitat in trickling seepages over rock. It is an adjective in the nominative singular.