Prionohydrus cambyreta, Urcola & Baca & Rodriguez & Michat, 2024

Urcola, Juan I., Baca, Stephen M., Rodriguez, Georgina & Michat, Mariano C., 2024, Prionohydrus cambyreta sp. nov. from Iberá wetlands-the first species of the genus from northern Argentina (Coleoptera: Noteridae), Zootaxa 5523 (4), pp. 483-493 : 484-491

publication ID	https://doi.org/ 10.11646/zootaxa.5523.4.7
publication LSID	lsid:zoobank.org:pub:045ED69D-0255-4E7D-8E15-EEA1045AB955
DOI	https://doi.org/10.5281/zenodo.13974024
persistent identifier	https://treatment.plazi.org/id/CE0AAA1D-4555-FFA5-C794-0515E635795A
treatment provided by	Plazi
scientific name	Prionohydrus cambyreta
status	sp. nov.

Treatment

Prionohydrus cambyreta sp. nov.

( Figs 1–7 View FIGURE 1 View FIGURE 2 View FIGURES 3 View FIGURES 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 )

Type locality. Argentina, Corrientes Province, Parque Nacional Iberá, Portal Cambyretá , 27°49’S 56°50’W, elevation 75 m a.s.l.; specimens collected by light trapping GoogleMaps .

Type material. Holotype ♂ labelled: “ ARGENTINA. Corrientes / Province. PN Iberá. Portal / Cambyretá 16.XI.2018 / Col.: Urcola JI ” [typed, white label], “HOLOTYPE / Prionohydryus cambyreta sp. nov. / Urcola et al. 2024 ” [typed, red label], “ MACN _En / 43449” [typed, white label] . Paratypes: same data as holotype, 15 ♂, 15 ♀ ( MACN-EN 43450 to 43479 ). All paratypes with the following label: “PARATYPE / Prionohydryus cambyreta sp. nov. / Urcola et al. 2024 ” [typed, yellow label] .

Diagnosis. Prionohydrus cambyreta sp. nov. is distinguished from other species of the genus by the following combination of characters: (1) ventral coloration red-brown (2) male antennae strongly expanded, (3) lateral flanges on sides of median lobe unequal, left lateral flange strongly expanded ventrally, (4) left lateral lobe with a tuft of very long hair-like setae on proximal third, followed by a second tuft of shorter hair-like setae, (5) lateral projection of left lateral lobe rounded, and (6) apex of left lateral lobe with a tuft of hair-like setae of different lengths.

Description of the holotype. Small sized beetle (TL = 2.1 mm). Body elongate, subovate, broadest at about basal third of elytra, posteriorly strongly attenuated apically ( Figs 1a–b View FIGURE 1 ); in lateral view dorsum convex, lateral outline slightly discontinuous between pronotum and elytron ( Fig. 1c View FIGURE 1 ).

Color ( Figs 1a–c View FIGURE 1 ). Head and pronotum reddish-brown; elytron slightly darker. Ventral coloration reddish-brown except abdominal ventrites and legs lighter; antennae and palpi orange brown.

Dorsal surface ( Fig. 1a View FIGURE 1 ). Head, pronotum, and elytron densely covered with moderately impressed isodiametric meshes ( Figs 1a, c View FIGURE 1 , 6b–d View FIGURE 6 ). Head broad, with very fine irregular micropunctation near internal margin of eyes; eyes medium-sized ( Fig. 1a View FIGURE 1 , HW/EW = 1.7). Pronotum convex, bead narrow posteriorly, evenly expanded anteriorly to broad anterior angle; surface with transverse row of micropunctation near anterior margin; anterior and lateral margins with golden setae. Elytra convex; maximum width at about anterior third; each elytron with five longitudinal rows of macropunctation, with long golden setae near lateral margin and on posterior region.

Ventral surface ( Fig. 1b View FIGURE 1 ). Head, thorax, legs, and abdomen dull, densely covered with moderately impressed isodiametric meshes ( Figs 1b View FIGURE 1 , 3 View FIGURES 3 ), except for somewhat more transverse meshes anteromedially on prosternum ( Fig. 3a View FIGURES 3 ) and somewhat more longitudinal meshes on lateral margin of prosternal process ( Fig. 3b View FIGURES 3 ). Antennae strongly expanded ( Figs 1a–b View FIGURE 1 , 2a View FIGURE 2 , 3a View FIGURES 3 , 4a–b View FIGURES 4 ); antennomeres I and II subequal in length; antennomeres III–V short, not strongly widened; antennomere VI–XI long, strongly widened, with microtrichia (groups of minute cuticular protuberances which lack socket) on ventral surface, denser on antennomeres X–XI ( Fig. 4a–b, e–f View FIGURES 4 ); antennomere XI longest; antennomere VII widest. Maxillary palpus with palpomeres I–III short; palpomere IV slightly shorter than first three combined, notched at apex. Labial palpus with palpomeres I–II very short, subconical; palpomere III as long as first two combined, broad and flat with small protuberance on inner margin. Prothorax with prosternum longitudinally relatively elongate, medially broadly convex ( Figs 1b View FIGURE 1 , 3a View FIGURES 3 ); apparently glabrous (under low magnifications, Fig. 1b View FIGURE 1 ) but with some minute, either hair-like or spine-like setae ( Fig. 3a View FIGURES 3 ); prosternal process ( Fig. 1b View FIGURE 1 , 3a–b View FIGURES 3 ) narrow between procoxae, then widening to subrectangular plate with lateral margins almost straight, posteriorly strongly attenuated with apex slightly rounded ( Figs. 1b View FIGURE 1 , 3b View FIGURES 3 ). Metacoxal processes ( Fig. 3a View FIGURES 3 ) subtriangular, with some short, stout setae scattered over entire surface, more abundant posteromedially; lateral margins slightly divergent posteriorly, metacoxal lobes evenly rounded with a cluster of setae apically ( Fig. 3d View FIGURES 3 ), posterior margin sinuate ( Fig. 1b View FIGURE 1 , 3a View FIGURES 3 ). Anterior leg ( Figs 2c View FIGURE 2 , 3a View FIGURES 3 ) with profemur short and broad, protibia short and rounded dorsoapically, with moderately large, weakly curved, apical spur and moderately large dorsal spur, with shortened fringe of setae along apical margin, with hair-like setae on dorsal margin and anterodistal surface; protarsus attached to apex of protibia, protarsomere I largest, as long as protarsomeres II–V combined, bearing a single suction cup ( Fig. 3c View FIGURES 3 ), protarsomeres II–IV subequal in length, protarsomere V slender, as long as protarsomeres II–IV combined. Medial leg ( Fig. 3a View FIGURES 3 ) with mesofemur and mesotibia long and slender; mesotibia with several moderately large spines, posterior spur strongly serrate ( Fig. 6a View FIGURE 6 ), mesotarsomere I as long as mesotarsomeres II–IV combined, with a single suction cup ( Fig. 3e View FIGURES 3 ). Posterior leg ( Figs 2d View FIGURE 2 , 3a View FIGURES 3 ) with metafemur broader (FW/FL = 0.46), with thick comb of long setae on posterodistal angle; metatibia long and somewhat broad, with several moderately large spines (smaller in size than mesotibial spines), a series of long natatory setae on inner margin, and two spurs on distal inner angle, posterior spur longest and strongly serrate, anterior spur not serrate ( Figs 2d View FIGURE 2 , 3a View FIGURES 3 , 6a View FIGURE 6 ). Claws subequal in length, without teeth. Abdomen subtriangular, composed of six ventrites; ventrites I–III fused; suture separating ventrite 1 from ventrite II well visible, suture separating ventrites II and III indistinct; ventrite VI subtriangular, with long golden setae at apex.

Male genitalia ( Fig. 5 View FIGURE 5 ). Sternite IX ring-like, posterior margin bilobed with deep notch, ventrite IX with an oval sclerotized area, apically protruding, apex pointed with several minute hair-like setae ( Fig. 5a View FIGURE 5 ); aedeagus asymmetrical; median lobe ( Fig. 5b–d View FIGURE 5 ) slender, in lateral view sinuate, then narrowing to rounded apex; curved dorsally at about mid-length; ventrally with deep longitudinal groove subtended by lateral flanges, left lateral flange ( Fig. 5b View FIGURE 5 ) enlarged, strongly expanded ventrally, converging with right lateral flange at or near apex; base comprised of right lateral notch and a medial hook-like process (left lateral notch reduced); right lateral lobe in lateral view ( Fig. 5e View FIGURE 5 ) short, subtriangular, laminar, narrow at base, broadening towards apex, with deep longitudinal groove on dorsal side, creating an inward fold; left lateral lobe large, heavily setose, in lateral view ( Fig. 5f–g View FIGURE 5 ) relatively elongate, broad, curved, with a tuft of very long hair-like setae on proximal third, followed by a second tuft of shorter hair-like setae, and an elongate and rounded projection on left side ( Fig. 5g View FIGURE 5 ); apex broad, rounded, with a tuft of hair-like setae of different lengths.

Measurements. Holotype [paratypes, mean]: TL = 2.1 mm [2.1–2.3 mm, mean = 2.19 mm]; GW = 1.1 mm [1.10–1.2 mm, mean = 1.15 mm]; PL = 0.5 mm [0.5–0.55 mm, mean = 0.51 mm]; PW = 1.0 mm [1.05–1.15 mm, mean = 1.08 mm]; HW = 0.7 mm [0.7–0.8 mm, mean = 0.75 mm]; FL = 0.4 mm [0.35–0.45 mm, mean = 0.40 mm]; FW = 0.2 mm [0.15–0.2 mm, mean = 0.18 mm]; SW = 0.1 mm [0.1–0.15 mm, mean = 0.14 mm]; TLVP = 0.9 mm [0.9–1.05 mm, mean = 0.99 mm]; TL/GW = 1.9 [1.80–2.0, mean = 1.91]; PL/PW = 0.5 [0.45–0.50, mean = 0.47]; HW/EW = 1.7 [1.67–1.88, mean = 1.73]; FW/FL = 0.5 [0.45–0.5, mean = 0.46]; GW/SW = 8.4 [7.85–9.6, mean = 8.73].

Female genitalia ( Fig. 7 View FIGURE 7 ). No conspicuous differences were observed with the female genitalia of P. matogrossensis .

Sexual dimorphism. Male antennae strongly expanded ( Figs 2a View FIGURE 2 , 3a View FIGURES 3 , 4a–b View FIGURES 4 ); females with antennae unmodified ( Figs 2b View FIGURE 2 , 4c–d View FIGURES 4 , 6a View FIGURE 6 ). Apex of prosternal process more rounded in females ( Fig. 6e View FIGURE 6 ) than in males ( Fig. 3b View FIGURES 3 ). Male proand mesotarsomeres I as large or larger than segments II–IV combined, bearing a single suction cup ( Figs 2c View FIGURE 2 , 3a, c, e View FIGURES 3 ); females with pro- and mesotarsomeres I large but smaller than segments II–IV combined, lacking suction cups.

Differential diagnosis. Prionohydrus species exhibit a high degree of morphological similarity and few reliable external characteristics are available for distinguishing between them. Only subtle differences in ventral coloration and in antennal shape of males and females serve as diagnostic characters ( Gómez & Miller, 2013). Therefore, a thorough examination of the genitalia is imperative for accurate species identification. In appearance, the new species closely resembles P. matogrossensis as it exhibits a ventral red-brown coloration and an evident sexual dimorphism in antennal shape, with the antennae of males strongly expanded and those of females unmodified. In contrast, P. marc has a ventral light yellow-brown coloration, and the antennae of males are only slightly expanded (unmodified in females). Prionohydrus ubercornis , on its part, exhibits the same ventral light yellow-brown coloration as P. marc , but in this case both males and females have strongly expanded antennae. Prionohydrus cambyreta sp. nov. can be differentiated from P. matogrossensis by the median lobe of male genitalia: the lateral flanges of median lobe are unequal in height in the new species ( Fig. 5b, d View FIGURE 5 ), whereas in P. matogrossensis they are subequal in height (Figs 9–10, in Gómez & Miller, 2013). Prionohydrus cambyreta sp. nov. has similar median and right lateral lobes as P. marc and P. ubercornis , but the left lateral lobe exhibits some differences. Prionohydrus ubercornis has a single tuft of hair-like setae on basal two thirds (Fig. 16, in Gómez & Miller, 2013), whereas the other two species present two tufts, one on proximal third composed of long setae, and a second tuft distal to the first one composed of shorter setae ( Fig. 5f–g View FIGURE 5 ). Finally, the left lateral lobe in P. cambyreta sp. nov. has an elongated and rounded projection on the left side ( Fig. 5g View FIGURE 5 ), and the apex bears a tuft of long hair-like setae of different lengths ( Fig. 5f–g View FIGURE 5 ), whereas in P. marc the projection is elongated and narrowed, and the tuft of hair-like setae on apex is composed of setae of similar length (Fig. 13, in Gómez & Miller 2013).