Suphisellus epleri, Baca, 2017

Baca, Stephen M., 2017, A new species of Suphisellus Crotch from Mexico (Coleoptera: Noteridae), Zootaxa 4323 (2), pp. 277-285 : 278-282

Suphisellus epleri sp. nov.

( Figs. 1–17 )

Type locality: Mexico, Veracruz, Municipio Emiliano Zapata , Laguna Miradores, 19°28’21’’N; 96°47’12’’W, elevation 900 m asl.

Type material. Holotype ♂ labelled: “ MEXICO : Veracruz, / E. Zapata, Laguna/ Miradores, 26.VI./ 1997, R. Arce col. Pantano” [typed, white label], “ HOLOTYPE / Suphisellus epleri / Arce-Pére z & Baca” [typed, red label] ( IEXA) . Paratypes (2339 total) same data as holotype, except “ 22.II.1997 ” (44 exs., IEXA); “ 28.III.1997 ” (139 exs., IEXA); “ 30.IV.1997 ” (80 exs., IEXA); “ 18.V.1997 ” (110 exs., IEXA); “ 26.VI.1997 ” (608 exs., IEXA, CNIN, MSBA, SEMC, MHNW); “ 30.VII.1997 ” (130 exs., IEXA); “ 28.VIII.1997 ” (357 exs., IEXA); “ 21.IX.1997 ” (443 exs., IEXA); “ 30.X.1997 ” (204 exs., IEXA); “ 16.XI.1997 ” (73 exs., IEXA) ; 7.XII.1997 (132 exs., IEXA), “ 11.I.1998 ” (18 exs., IEXA). All paratypes with the following label: “PARATYPE Suphisellus epleri Arce-Pére z & Baca” [typed, yellow label].

Diagnosis (Male): Head, pronotum, antennae, palpi and legs yellow; elytra brownish-red, with three longitudinally elongated yellow spots ( Figs. 1, 3 ); elytra and base of pronotum punctate, surface with microreticulation appearing as thin irregular cells ( Fig. 4 ); Prosternum as in Figs. 9 , 17 , with transverse row of setae consisting of 8–12 thick setae among smaller, more sporadic setae; prosternal process with apex broad, truncate, with straight posterior margin ( Fig. 17 ). Male genitalia with median lobe curved, slender, with parallel lateral margins and rounded apex in dorsal aspect ( Fig. 19a ); width nearly uniform along length in lateral aspect, slightly wider in apical third with rounded apex ( Figs. 19a, c ))

Description. Holotype (Male): Small beetle, TL = 2.75 mm; body oval, dorsum moderately convex, broadest near base of elytra and posteriorly attenuated with narrowly rounded apex ( Fig. 1 ), lateral margin continuous between pronotum and elytron ( Figs. 1, 3 ).

Appearance and color. Elytra brownish-red, with three longitudinally elongated yellow spots ( Figs. 1, 3 ); dorsal surface with microreticulation appearing as transversally elongated irregular cells ( Fig. 4 ); posterolateral angle on pronotum with clearly marked crease extending up to anterior half of pronotum ( Fig. 5 ). Venter yellowishred; noterid platform flat, subrectangular with abundant short, thick setae scattered on surface ( Figs. 2 , 9 , 17 ).

Head. Broad, surface with indistinct sculpture, with weak setiferous punctation along the internal margin of the eyes; color yellow, darker at base and frontal region, eyes large ( Figs. 1 , 6 ). Antennae 11-segmented; scape short, subconical; pedicel subrectangular; antennomeres III–VI short, subconical; antennomeres VII–X subconical, larger than antennomeres III–VI; antennomere XI long, acuminate ( Figs. 1 , 6 ). Maxillary palpus four-segmented; palpomeres I–III short, subconical; palpomere IV clearly notched at apex. Labial palpus four-segmented; palpomeres I–III very short, subconical; palpomere IV larger than first three combined, broad and flat with small protuberance at inner lateral margin ( Fig. 7 ).

Thorax. Pronotum convex, with lateral bead narrow; punctation scattered; anterior and lateral margins with punctures producing long, thin golden setae, anterior margin with series of semicircular dark spots ( Fig. 1, 3 ); crease at posterolateral angle clearly demarcated, extending to pronotal half length ( Fig. 5 ). Elytra moderately convex; with maximum width slightly anterior to half of total length (TL) in dorsal view, with lateral margins widely curved, attenuated posteriorly to narrowly rounded apex; elytral surface with punctation more dense than pronotal surface, some punctures with long golden setae on base, lateral margins, and apical region ( Figs. 1, 3 , 4, 8 ); each elytron with three yellow elongated longitudinal spots, one on elytral disk at 1/2 elytral length, a second at 3/4 elytral length, nearer to elytral suture, and a third irregular spot at lateral margin; all spots isolated, not joining ( Figs. 1, 3 ). Prosternum with anterior margin sinuate, prosternal disc with comb of 11 stout setae medially, anterior to procoxae and prosternal process; prosternal process with length greater than width, narrow between procoxae, with lateral margins distinctly separated ( Fig. 17 ), apically broad and subtriangular, with weak medial longitudinal groove, apex truncate, posterior margin nearly straight. Metaventrite large, posteriorly continuous with noterid platform, rounded and notched anteriorly to receive apex of prosternal process. Noterid platform with lateral margins curved anteromedially anteriorly and subparallel posteriorly, posteriorly divided into two subtriangular lobes (metacoxal processes) separated by a deep angular notch medially ( Figs. 2 , 9 ). Prosternal process and noterid platform with short, stout setae scattered over entire surface, metacoxal lobes each with thick setal comb at anteroapical margins ( Fig. 2 , 9 ).

Legs. Protibiae with comb of long setae on the outer margin, apex with robust, curved spur ( Fig. 2 , 9 ). Protarsus with protarsomere I large, subtriangular, larger than protarsomeres II–IV together ( Fig. 10 ). Metafemora broad with thick comb of long setae at distal angle ( Fig. 11 ). Tibiae and tarsi of meso- and metalegs with series of long natatory setae. Metatibiae with posterior spur serrate.

Abdomen. Triangular; ventrites smooth. Ventrite I not visible, hidden under metacoxae in ventral aspects; ventrites II–VII visible; ventrite II divided by metacoxae; ventrites III and IV fused, sutures indistinct; ventrites V and VI each with transverse row of strong punctures; punctures producing long golden setae; ventrite VII subtriangular, with large shallow impression medially, surface with scattered long setae, more abundant at apex ( Figs. 2 and 11 ); ventrite VIII hidden under ventrite VII, triangular, notched posteromedially.

Male genitalia. Genital segment (ventrite IX), long, subrectangular, with apex strongly bifurcate ( Fig. 15 ). Median lobe longer than lateral lobes, slender with lateral margins subparallel and apex rounded in dorsal aspect; curved in lateral aspect ( Fig. 12 ), with width nearly uniform, slightly wider at apical third, with rounded apex. Right lateral lobe short, subtriangular, laminar, narrow at base and broad towards the apex. Left lateral lobe ( Fig. 13 ) curved in lateral aspect, slightly widened at apical third, apex attenuate on dorsal margin, irregular near apex ( Fig. 14 ), with long golden setae in apical third ( Figs. 13, 14 ); ventral margin sinuate at the base and curved towards the apex.

Female genitalia (paratype). Laterotergites long and slender, with expanded anterior portion ( Fig. 16a ). Gonocoxae long, oval, with sharp posterior apex and smooth margins. Gonocoxosternite large, laminar, subtriangular, broad anteriorly and attenuate posteriorly, with long and short longitudinal edges on surface ( Fig. 16b ).

Measurements. Holotype (paratype measurements in square brackets []): Holotype: TL = 2.75 mm [2.55– 2.90 mm, mean = 2.72 mm]; GW = 1.45 mm [1.25–1.45 mm, mean = 1.35 mm]; TL/GW mean = 1.9 mm; TLVP = 1.24 mm [1.20–1.30 mm, mean = 1.25 mm]; HW= 0.78 mm [0.74–0.84 mm, mean = 0.79 mm]; EW = 0.39 mm [0.38–0.44 mm, mean = 0.41mm]; Male genitalia (Holotype): median lobe length = 0.52 mm; right lateral lobe = 0.28 mm, width = 0.16 mm; left lateral lobe = 0.50 mm. Female genitalia (Paratype): gonocoxosternite = 0.42 mm.

Variability. There was no strong variation observed in shape and size. The dark spot on the head varies in position and size. Elytral color varies from dark brown to light reddish- or yellowish-brown; colors of the head, pronotum, venter and legs vary in relative darkness accordingly with elytra. Elytral pattern varies substantially among the observed specimens, with spots varying in prominence, length, and width. In some specimens, the patterning is quite reduced, with spots very small or indistinct; the elongate longitudinal spot nearest the elytral suture ( Fig. 1 ) is often not present in specimens with reduced patterning. In contrast, patterning is very prominent in some specimens; many were observed to have an additional spot near the base of the elytra, sometimes the spot on the elytral disc extends anteriorly to meet this spot; some specimens also have a visible oblique spot or stripe near the apicolateral margin of the elytra; the pattern of such specimens is similar in appearance to S. varians as depicted in Fig. 1 of Young (1979). Ventral color ranges from yellowish-red to entirely yellow.

Differential diagnosis. Suphisellus epleri sp. nov. appears very similar to S. neglectus Young, 1979 due to its body shape and size, dorsal ornamentation and male genitalia, but it is easily distinguishable by the apex of the median lobe of the aedeagus, which in S. epleri is generally of uniform width and broadens only slightly in lateral aspect ( Fig. 19a, c ). In specimens of S. neglectus , the median lobe is slender along its length to apex, where it is distinctly broadened into an ellipsoid lobe in lateral view ( Fig. 20a, c ). This shape of the aedeagus of S. neglectus remains quite consistent among observed specimens. Externally, the setal comb on the prosternum is generally more robust in S. epleri , with ca. 8 or more stout setae and several smaller ones ( Fig. 17 ); in observed specimens of S. neglectus this comb consisted of ca. 4–8 stout setae mingled with only a few smaller ones ( Fig. 18 ). Also, though the prosternal process is very narrow between the procoxae of both species, in S. neglectus it is slightly, but consistently narrower in this region, with the margins elevated from the surface (in ventral aspect) and convergent anteriorly, often nearly touching as they approach the setal comb of the prosternum ( Fig. 18 ). In S. epleri the prosternal process is less narrow between the procoxae, with the margins subparallel anteriorly and not as strongly convergent approaching the setal comb of the prosternum ( Fig. 9 , 17 ). The prosternal process of S. epleri is generally wider and more truncate than S. neglectus , with the posterolateral margins more sharply angled and the posterior margin straight ( Fig. 17 ). In S. neglectus , the apex of the prosternal process is less truncate, with posterolateral margins and posterior margin more rounded, ( Fig. 18 ), though there is some variation in degree roundness of the apex of prosternal process among specimens of S. neglectus . Finally, the medial groove on the prosternal process ( Young, 1979) appears to be more deeply impressed in S. neglectus than in S. epleri . As an observational note, it appears that this groove comprises several deep, close, and non-setiferous punctures in both specimens ( Figs. 9 , 17, 18 ).

Distribution. So far known only from the type locality ( Fig. 21 ). There is no evidence of sympatry of the new species with Suphisellus neglectus . This latter, in fact, is distributed from northern South American ( Colombia and Venezuela), north through Central America ( Panama), to Belize and Guatemala. A dubious record is known from Teapa, Tabasco, Mexico (question mark in Fig. 21 ), but the poor condition of the specimens does not allow their clear identification ( Young 1979). With this data, the northernmost record of S. neglectus is in Paso Antonio, Masagua, Escuintla, Guatemala 45 m a.s.l. (14.05°N, 90.71°W) on the Pacific slope (Young 1970), 870 km from the type locality of S. epleri in Veracruz, Mexico, on the slope of the Gulf of Mexico.

Etymology. This species is dedicated to Dr. John Epler because of his contribution to knowledge on aquatic Coleoptera in North America. The name is a noun in the genitive singular.

Habitat and Biology. Adults of S. epleri were captured in the swampy environment of the lagoon. They were found in greater abundance during the rainy season and presenting a sex ratio of 1:1 (one female per male) in a sample of 100 specimens. S. epleri cohabits with other species of Noteridae ( Suphisellus lineatus ( Horn, 1871) , S. nigrinus (Aubé, 1838) , Hydrocanthus marmoratus Sharp, 1882 , Mesonoterus laevicollus Sharp, 1882 , Notomicrus sharpi J. Balfour-Browne, 1939 ), as well as other aquatic beetles: Dytiscidae ( Rhantus Dejean , Copelatus Erichson , Celina Aubé , Thermonectus Dejean , Laccophilus Leach ) and Hydrophilidae ( Berosus Leach , Tropisternus Solier , Enochrus Thomson , Paracymus Thomson , Hydrophilus Geoffroy ).

Figures

FIGURE 21. Distribution map of Suphisellus epleri sp. nov. (single star in Mexico) and of S. neglectus (circles). The question mark indicates the doubtful record of S. neglectus for Mexico (Teapa, Tabasco).

FIGURES 1 – 3. Suphisellus epleri (male paratype): 1) Habitus, dorsal aspect; 2) Habitus, ventral aspect; 3) Habitus, lateral aspect; scale bar 0.5 mm.

FIGURES 4 – 11. SEM images of Suphisellus epleri: 4) Elytral surface (higher magnification); 5) Posterolateral angle crease; 6) Head and antennae; 7) Ventral view of head showing maxillary and labial palpi; 8) Elytral surface (lower magnification); 9) Venter, showing noterid platform and legs; 10) Protarsus; 11) Abdomen, ventral aspect.

FIGURES 12 – 16. SEM images of Suphisellus epleri sp. nov. Male genitalia in lateral view. 12) Median lobe; 13) left lateral lobe; 14) left lateral lobe, apical third; 15) genital segment; 16) Female genitalia in lateral view. a) view of entire genital complex, with laterotergites and gonocoxosternites; b) detail of gonocoxosternites.

FIGURES 17 – 18. Prosternum of male specimens of 17) S. epleri and 18) S. neglectus (ex. Colombia).

FIGURES 19 – 20. Aedeagi of 19) S. epleri and 20) S. neglectus. a) median lobe, left lateral aspect; b) median lobe, dorsal aspect; c) median lobe, right lateral aspect; d) left lateral lobe; e) right lateral lobe.