Canthysellus peruanus Baca and Toledo

Baca, Stephen M. & Toledo, Mario, 2015, CanthysellusBaca and Toledo (Coleoptera: Noteridae: Noterini), a New Genus of Burrowing Water Beetle from South America, The Coleopterists Bulletin 69 (3), pp. 477-488 : 486-487

Canthysellus peruanus Baca and Toledo new species

( Figs. 3 , 5 , 7 , 10 , 12 )

Type Locality. Peru, Madre de Dios Region, Río Tambopata .

Type Material. Holotype (male): “ PERU: Rio Tambopata / Explorer’ s Inn / 12°50.208′ S 069° 17.605′ W / 10 December 2003 / coll. K.B. Miller ” [Printed], “Photo Voucher/ PV__/ Short Lab – KU NHM” [green label, printed], “ HOLOTYPE / Canthysellus / peruanus / Baca & Toledo, 2015” [red label, printed] ( MSBA) . Paratypes (11 specimens): Same data as holotype. (3 males; 6 females exs. MSBA, 1 male; 1 female exs. SEMC). All paratypes with “ PARATYPE / Canthysellus / sipaliwini / Baca & Toledo, 2014” [blue label, printed] .

Diagnosis. Canthysellus peruanus is distinguished by the following combination of characters: (a) metatibia as in Fig. 7 , with inner margin densely setose, setae slender, hair-like, metatarsomere I similarly setose; (b) line of setae on prosternum as in Fig. 5a , not extending laterally past lateral margins of narrowest portion of prosternal process; (c) aedeagus as in Fig. 10a–e , median lobe only weakly expanded ventrally, distally parallelsided and weakly attenuate to subtruncate apex in lateral aspect ( Fig. 10a, c ), left lateral lobe with dense tuft of setae produced from weakly lobed apex ( Fig. 10d ).

Description. Holotype.Male. Color and appearance: Shiny, elytra superficially iridescent; maculate, weakly bicolorous with elytra only slightly darker than head and pronotum. Color of head, pronotum, and maculae reddish brown; color of elytra very dark reddish brown; maculae as in Fig. 3 , each elytron with 1 spot distally near apex and with an irregular band near elytral midlength extending from lateral margin to suture, often broken into a series of 2 or 3 spots with margins blurred and meeting. Color of venter dark reddish brown, with color of noterid platform and sutures only slightly darker than rest of ventral surface; color of legs slightly lighter than venter, margins dark. Head: Dorsal surface with microsculpture consisting of small, round, isodiametric cells. Thorax: Pronotum with lateral bead broad, 1.13X width of antennomere VII. Prosternum medially with close, transverse line or tuft of 5 stiff setae, line of setae continuous medially, not extending past lateral margins of prosternal process. Prosternal process and noterid platform setose, setae very short, stout, produced from punctures, distinctly spaced and evenly distributed ( Fig. 5 ). Metatibia densely setose on inner margin ( Fig. 7a ); setae slender, hair-like, expanding from single line at base to dense field distally; field restricted to inner margin. Metatarsomere I with inner margin similarly setose to metatibia. Abdomen: Aedeagus as in Fig. 10a–e ; median lobe curved dorsally, divided ventrally by deep groove, groove ceasing and sides meeting at about midlength of lobe, left side expanded ventrally at midlength, distal third of lobe subparallel and distally attenuate to truncate apex in lateral aspect, distal portion distinctly curved in dorsal aspect; left lateral lobe broad, weakly curved toward median lobe, with dense setal tuft produced apically from inner surface of weakly lobed apex ( Fig. 10d ); right lateral lobe broad, ventral margin broadly rounded ( Fig. 10e ). Measurements: Holotype: L = 3.10 mm; TL = 3.40 mm; GW = 1.90; HW = 1.05; EW = 0.65; PntB = 0.09 mm; AntVII = 0.08; HW/EW = 1.62; PntB/AntVII = 1.13. Paratypes: L = 3.05– 3.35 mm, males = 3.10–3.35 mm, females = 3.05–3.30 mm; TL = 3.25–3.40 mm; GW = 1.9– 2.1 mm; HW = 1.00– 1.10 mm; EW = 0.55–0.65; PntB = 0.7–0.9; AntVII = 0.07–0.08; L/GW = 1.55–1.65; HW/EW = 1.59–1.75; PntB/AntVII = 1.00–1.25.

Variation. Variation in C. peruanus is difficult to accurately assess as all examined specimens were part of a limited series from a single collecting event. The variation that was observed was primarily limited to slight differences in size.

Biology. Though specific habitat data for C. peruanus were not recorded on specimen labels, the series of specimens is believed to have been collected from a marshy inlet or pond just south of the Explorer’ s Inn (K. B. Miller, personal communication), a lodge on the Río Tambopata in the Madre de Dios region of Peru.

Distribution. Canthysellus peruanus is known only from a single series of specimens collected from the Madre de Dios region in Peru ( Fig. 12 ).

Remarks. The setae of the inner margins of the metatibia and first metatarsomere are excellent for distinguishing C. peruanus from other members of Canthysellus . However, it should be noted that these setae are often clumped on dried specimens and to the observer may at first appear as stout setae.

Etymology. The specific epithet refers to the country where this species was collected, meaning ‘inhabiting Peru’. It is treated as an adjective in the nominative singular.

Figures

Figs. 1–3. Canthysellus species, dorsal and lateral habitus. 1) C. buqueti, male; 2) C. sipaliwini, holotype, male;

Figs. 4–5. Canthysellus species, pro- and metasterna and metacoxae (noterid platform) with studies of prosternal setae. 4) C. buqueti, male, a and b = variation of prosternal setae; 5) C. peruanus, paratype, male, a = enlarged view of prosternal setae. Scale bar = 0.5 mm.

Figs. 6–7. Canthysellus species,hind legs.6) C.buqueti, male, a = setae of inner margin of metatibia, b = posterior metatibial spur, serration is diagnostic of the genus; 7) C. peruanus, paratype, male, a = setae of inner margin of metatibia. Scale bars = 0.25 mm

Figs. 8–10. Canthysellus species, aedeagi. 8) C. buqueti, Suriname; 9) C. sipaliwini, holotype, Suriname; 10) C. peruanus, paratype, Peru. 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. Scale bars = 0.25 mm.

Fig. 12. Distribution map of Canthysellus species.