Hydroporus karabegan, Aykut & Tusun & Fery, 2025

Aykut, Medeni, Tusun, Sadreddin & Fery, Hans, 2025, Hydroporus karabegan sp. nov. from eastern Türkiye (Coleoptera, Dytiscidae, Hydroporini), Zootaxa 5609 (1), pp. 125-131 : 126-130

Hydroporus karabegan sp. nov.

Type locality: Türkiye, Elazığ province, Arıcak district, Akdağlar plateau, ca. 7 km N Arıcak , 38°37’18’’N 40°08’06’’E, altitude ca. 2,180 m .

Type material: Holotype: ♂, “ 4.6.2024 (TR) Elazığ prov. / Arıcak distr., Akdağlar plateau / ca. 7 km N Arıcak ”, “ 38°37’18’’N 40°08’06’’E, ca. / 2180 m, muddy-grassy spring / water, M. Aykut & S. Tusun leg.” [printed], “Holotype / Hydroporus / karabegan sp. nov. / Aykut, Tusun & Fery det. 2005” [red, printed] . Paratypes: 7 ♂, 2 ♀, same label texts as holotype; 8 exs, idem, but date 28.8.2024; all paratypes with a respective red label .

Description of the holotype

Habitus in dorsal view elongate oval, subparallel ( Fig. 1 ); body outline with very slight discontinuity between pronotum and elytra; maximum width situated near middle of total length; dorsal surface predominantly black, reticulate, not matt but with silky shine; ventral surface largely black, but less reticulate and more shiny.

Head black, on vertex shining through dark brownish; antennomeres brownish; third and fourth shorter than second and fifth; fifth to eleventh in apical half darkened. Clypeus with two interocular grooves behind anterior margin. Punctures on head rather fine; centrally evenly distributed, distance between punctures about four times that of their diameter; near anterior margin punctures still finer and denser, on vertex finer and sparser, in clypeal grooves very dense; alongside inner margin of eyes with line of dense and coarse punctures.

Pronotum black, lateral beading (rim) near pronotal base dark brownish; maximum width between posterior angles; sides in posterior two thirds almost straight, converging anteriad, in anterior third weakly curved inwards; rim relatively broad, near anterior angle somewhat broader. Centre of disc with one very coarse puncture; nearby punctation slightly finer and much sparser than on clypeus of head; more laterally and medially before hind-margin punctation more or less as coarse as on clypeus; immediately behind anterior margin with very fine punctures; behind with irregular medially interrupted row of coarse punctures; near posterior angles with an oblique depression, here punctures especially dense and coarse and meshes of reticulation smaller and more impressed.

Elytra black except dark brownish lateral rim in posterior half. Punctation on disc more or less uniformly distributed; punctures coarser than those on centre of head and on pronotum, laterally and apically somewhat smaller; alongside suture with narrow longitudinal unpunctured stripe on each elytron. Distance between punctures on disc about three times that of their diameter. Disc of each elytron with two puncture lines, however inner (= first) one almost undiscernible, at least a very few punctures very slightly larger than punctures between lines; second and third discal line better recognisable, marginal puncture quite distinct. Margin of elytra with shiny rim over entire length, slightly narrower than pronotal rim; in strictly perpendicular view onto upper surface rim only visible near shoulders and in posterior third of elytra because sides of elytra projecting over margin and obscuring it. In lateral view lateral margin weakly ascending to shoulders; epipleuron distinctly visible until shoulders. Setae on disc present, laterally and posteriorly somewhat longer and more distinct.

Ventral surface black except legs, palpomeres and mouth parts. Reticulation only weakly impressed, thus surface shiny; on medial parts of metaventrite and of second abdominal ventrite and on intralinear space of metacoxae practically absent. Punctation on metacoxal plates, sides of metaventrite and on first two abdominal ventrite coarse; on epipleura somewhat less coarse; on centre of metaventrite, on intralinear space of metacoxae and third to fifth of abdominal ventrites less coarse and sparser, on sixth ventrite again somewhat coarser, here also transverse longitudinal reticulation more impressed; apex of last ventrite narrowly smooth. Most punctures on venter with a seta; centre of third abdominal ventrite with a large puncture and a few longer setae; a similar puncture on fourth ventrite less distinct. Gula with a few coarse punctures, laterally strongly sculptured, medially with traces of reticulation; genae distinctly reticulate. Prosternal process very narrowly lanceolate ( Fig. 2 ), tectiform in crosssection, sides beaded and provided with long setae. Prosternal column between procoxae with a protuberance, sub-basally with a few transverse ridges; middle of prosternum very rugosely sculptured. Posterior margins of metacoxal processes appearing sinuate because interlaminary bridge exposed, not concealed (see Fig. 3 ; for the term “interlaminary bridge” see Fery & Ribera 2018); metacoxal lines diverging anteriorly, not reaching posterior margin of metaventrite ( Fig. 3 ).

Legs brownish, coxae and trochanter partially darkened; femora diffusely darkened in proximal two thirds. First three pro- and mesotarsomeres broadened; first protarsomere with four rows of sucking setae; each row with two elongate oval cups; second protarsomere also with sucking setae, but only few with with cups, these being smaller than on first tarsomere; others with very small and circular cups; first mesotarsomere with three rows of distinct sucker cups, no large cups on second mesotarsomere. Protarsal claws more or less of same length, posterior (outer) claw strongly curved near base, almost evenly curved over rest of length; anterior (inner) claw more strongly curved near base and more or less straight in medial part, distally again slightly curved; mesotarsal claws of same length and evenly curved, distinctly thinner and somewhat longer than protarsal claws. First two metatarsomeres with a very few swimming hairs.

Males: Median lobe of aedeagus in ventral and lateral view as in Figs 4a, b , left paramere as in Fig. 5 .

Females: Without conspicuous external differences to males except slightly narrower pro- and mesotarsomeres, lack of sucker cups, and more evenly curved protarsal claws. Gonocoxosternum and gonocoxae as in Figs 6 and 7 .

Measurements: TL: 3.6–4.0 mm, MW: 1.9–2.1 mm, TL/MW 1.89–2.10; holotype: TL: 3.9 mm, MW: 1.95 mm, TL/MW: 2.0 (n = 16).

Variability: Apart from size and deviating characteristics of male and female tarsi, no significant external differences were observed between the examined specimens. In a few specimens posterior part of pronotal rim and legs somewhat lighter brownish and prosternal process as well as hind margin of metacoxal processes also more brownish.

Notes: The wings of one male paratype were studied; they seem to be well developed, not reduced, at least about 1.5 times as long as elytra.

Distribution and habitat: So far the new species is only known from the type locality in eastern Anatolia. The specimens were found in a spring with little running water ( Figs 10, 11 ). As known from other members of the longulus -group the specimens were not collected in the water itself, but in the muddy-grassy border of that spring. Similar collecting sites are known for other species of the longulus -group (e.g. H. longulus Mulsant & Rey, 1861 , H. constantini Hernando & Fresneda, 1996 , and H. hajeki Fery, 2009 ; see the habitat photos of the latter two species in Fery 2009: 554).

Etymology. The specific name of the new species relates to “Karabegan”, a historical name of the Arıcak district. It is a noun in the nominative singular standing in apposition to the generic name.

Differential diagnosis

The new species is similar to Hydroporus holzschuhi and H. erzerumensis , both also from Türkiye. Compared to the former it is somewhat more elongate because of the slightly more parallel sides of the body. The two species are best distinguished by the shape of the median lobe (cf. Figs 4 and 8 ). Both have the distal part in ventral view evenly rounded; however, the lobe of the new species is distinctly broader. In lateral view, the lobe of H. holzschuhi is basally much more bent and in distal third more or less straight. That of the new species is basally less bent and in distal third still slightly curved. From the more northern H. erzurumensis the new species can be clearly distinguished by the shape of the distal part of the median lobe in ventral view ( Fig. 9 ). For comparison with other species from the Eastern Mediterranean region see Fery (2009) and Fery & Erman (2009).

Differences in the shape of the parameres and female genitalia between the three species have also been recognised but, considering the small amount of specimens of H. holzschuhi and H. erzurumensis to our disposal we refrain from giving details since we believe that distinguishing the species based solely on female characters is not at all trustworthy (as it is in most species of the longulus -group).

Notes: The distance between the collecting site of the new species and that of H. holzschuhi is only about 95 km. Therefore, at first glance, it is somewhat surprising that two different species were found in areas so close to each other. However, it must be considered that the Akdağlar plateau in the Akdağ mountains and the Şerafettin mountains (area of H. holzschuhi ) are separated by the Murat River basin. Additionally, the Akdağ mountains belongs to the Maden mountain range, a part of the eastern Taurus mountains group, and consists of a wide variety of sedimentary rocks, primarily volcanic rocks, which is called the Maden Complex in terms of lithology. The Şerafettin mountains, on the other hand, consist of basalt, andesite and tufa ( Nehme et al. 2023).

Figures

FIGURE 1–3. Hydroporus karabegan sp. nov.: (1) habitus and labels; (2) ventral side, prosternal process; (3) ventral side, metacoxal lines and processes.

FIGURE 4–9. (4–7) Hydroporus karabegan sp. nov.: (4) median lobe of aedeagus (a: ventral view, b: lateral view); (5) left paramere; (6) gonocoxosternum; (7) gonocoxae. (8–9) median lobe of aedeagus of (8) Hydroporus holzschuhi Fery, 2009 (redrawn from Fery 2000: 536); (9), idem of H. erzurumensis Erman & Fery, 2000 (redrawn from Erman & Fery 2000: 174).

FIGURE 10–11. Habitat of Hydroporus karabegan sp. nov.; for comparison with similar habitats of other members of the H. longulus group see figs 27–32 in Fery (2009: 554).