Tychepsephus cekalovici, Shepard & Barr, 2023

Shepard, William D. & Barr, Cheryl B., 2023, A revision of the Chilean water penny genus Tychepsephus Waterhouse, 1876 (Coleoptera, Psephenidae, Eubriinae), with description of a second species and two larval morphotypes, and notes on other Chilean Psephenidae, ZooKeys 1164, pp. 23-61 : 23

Tychepsephus cekalovici sp. nov.

Figs 7 , 8-9 , 11 , 18-19 , 20 , 21-23

Type locality.

Chile: Región X (Los Lagos), 3.5 rd. km W of Nueva Braunau, Puente Colegual, Río Colegual, -41.3264°, -73.1225°, 158 m, sweeping riparian vegetation, 8 January 2003, William D. Shepard leg. (Fig. 8 ).

Type material.

Holotype male, pinned. "CHILE: Region X / 9 km E Loncotoro / 8 I 2003 650' / Pte Colegual 2 [ Río Colegual] (WDS-A-1519) [on reverse] // William D. Shepard, leg. // [genitalia in vial below specimen] // HOLOTYPE / Tychepsephus / cekalovici / Shepard & Barr [red handwritten label]". Deposited in the MNNC.

Other material examined.

Paratypes (67). Chile: Region X, 3 km W Nueva Braunau, Rio Colegual , 30 XII 2002 (WDS-A-1502) [on reverse], William D. Shepard, leg. (9; EMEC, 6, 5♂ 1♀; MNHN, 1♂; MNNC, 1♂; NHMUK, 1♂) ; Chile: Región X Lagos , Río Colegual 3.5 rd. km W Nueva Braunau, elev.160' [49 m], 41°19.58'S, 73°07.35'W, 30 Dec. 2002, C. B. Barr, sweeping willows and other riparian vegetation (11; EMEC, 9, 8♂, 1♀; MNNC, 1♂; NHMUK, 1♂) ; data as above, 31 Dec. 2002 (EMEC, 5♂); data as above, 8 Jan. 2003 (14; EMEC, 10, 8♂ 2♀; MNHN, 2♂; MNNC, 1♂; NHMUK, 1♀); Chile: Region X, 9 km E Loncotoro, Pte. Colegual 2, 650' [198 m], 8 I 2003 (WDS-A-1519) [on reverse], William D. Shepard, leg. (10; EMEC, 6, 4♂ 2♀; MNHN, 1♀; MNNC, 2, 1♂ 1♀; NHMUK, 1♂) ; Chile: Región X Lagos , Río Colegual, 8 rd. km W Llanquehue, elev.700' [213 m], 41°16.51'S, 73°06.52'W, 8 Jan. 2003, C. B. Barr, sweeping willows & other riparian vegetation (10; EMEC, 9, 6♂ 3♀; MNNC, 1♀) ; Chile: 8 mi W of Puerto Varas , 1-16-51, Ross and Michelbacher, CAS (CASC, 1) ; Chile: Region X, 20 km N Chaitén, unnamed stream [trib. Rio Blanco ], 520' [158 m], 3 I 2003 (WDS-A-1511) [on reverse], William D. Shepard, leg. (EMEC, 1♂) ; Chile: Region X, Rio Contaco , 520' [158 m], 9 I 2003 (WDS-A-1521) [on reverse], William D. Shepard, leg. (EMEC, 3, 1♂ 2♀) ; Chile: Corral , Dec 1905, R. Thaxter, MCZ (MCZC, 3) .

Differential diagnosis.

Males of T. cekalovici sp. nov. (Figs 18 - 20 ) are considerably smaller (3.3-3.9 mm long) than males of T. felix (4.6-5.2 mm long); the pronotal cuticle is dark brown to black with pale lateral and basal margins, and an elongate yellow spot anterior and adjacent to the scutellar shield; the elytral cuticle is usually yellow-brown with dark markings in a zig-zag pattern, but may be mostly plain, without patterning; the depressed frontal area between the eyes has a narrow, inverted Y-shaped sulcus; and abdominal ventrite 3 has a prominent, raised, golden yellow setal patch extending the full length of the ventrite (Fig. 18b ).

In contrast, males of T. felix (Figs 13 , 14 ) are much larger than those of T. cekalovici sp. nov.; the pronotal cuticle is dark brown to black with pale lateral margins and no yellow discal markings; the elytral cuticle is dark brown or red-brown, with setal patterning only; the depression between the eyes does not have an inverted Y-shaped sulcus; and abdominal ventrite 3 has a median, golden yellow setal patch that is not distinctly raised and does not extend the entire length of the ventrite (Fig. 13b ).

The aedeagi (Figs 14 , 19 ) of the two species are clearly different. In T. cekalovici sp. nov. (Fig. 19 ) the parameres have curved lateral margins and curved medial margins, and the apices are broad. In T. felix (Fig. 14 ), the parameres have straight lateral margins and only slightly curved medial margins, and the apices are narrow.

Like the males, females of T. cekalovici sp. nov. (Figs 21 , 22 ) are much smaller (3.3-3.9 mm long) than females of T. felix (4.3-5.7 mm long), and most have elytra with transverse yellow bands in a zig-zag pattern. Individuals of T. cekalovici without elytral patterning usually may be distinguished by a mediobasal yellow or yellow-brown spot, sometimes faint, on the pronotum anterior to the scutellar shield. In contrast, females of T. felix (Fig. 15 ) have brown elytra without yellow banding, and do not have a mediobasal yellow spot on the pronotum.

Description.

Male (Figs 18 - 20 ). Body: dorsally and ventrally covered with moderately long, coarse, yellow setae and shorter, thinner, silky, black setae; cuticle with closely spaced punctures, punctures finer ventrally. Cuticle of head, pronotum and venter dark brown to black; pronotum with yellow margins; elytra usually yellow-brown with dark brown patterns. Length 3.3-3.9 mm, width 2.0-2.6 mm (n = 19). Head: covered with moderately long, yellow setae. Vertex between eyes slightly wider than diameter of an eye. Frons deflexed at 90° angle from vertex; moderately deep depression between eyes containing a narrow, inverted Y-shaped sulcus, arms of Y deeply incised. Frontoclypeal suture absent. Clypeus wider than long, narrow at base; anterolateral angles curved beneath antennal bases. Maxillary palpus with four palpomeres; palpomeres 1-3 yellow-brown; 4 dark brown, obliquely hatchet-shaped, weakly curved at apex. Labial palpus light to dark brown, with three palpomeres, palpomere 3 truncate to weakly curved; glossae and paraglossae apically bifid and acicular. Antenna weakly serrate, with 11 antennomeres; 1 longest, cylindrical, yellow; 2 half as long as 1, yellow-brown; 3-11 dark brown, each wider apically. Antennal base encircled by raised margin. Eye large, bulbous, finely faceted. Pronotum: a little more than twice as wide as long, widest just anterior to base; all margins yellow; anterior margin slightly sinuate, convex between anterior angles; anterior angles prominent, broadly rounded, projecting anteriorly, clasping eyes; lateral margins finely sculptured with shallow notches, margins straight to basal 1/3 then curved to posterior angles; posterior angles slightly obtuse; posterior margin crenulate, straight laterally then curved to scutellar shield, straight anterior to scutellar shield; disc convex at middle, depressed near anterior angles; disc anterior to scutellar shield with an oblong, subbasal yellow spot and a short, shallow, median sulcus. Scutellar shield: pentagonal, as long as wide; anterior margin crenulate; disc flat, depressed, densely covered with coarse yellow setae. Elytra: conjointly longer than wide, widest ~ 1/3 the distance from apices, wider than pronotum; each elytron with anterior margin crenulate; lateral margin yellow, smooth, narrowly explanate; humerus moderately prominent; elytral base depressed between humerus and scutellar shield; area adjacent to lateral margin in anterior 1/2 with a wide, moderately deep depression; disc more convex in posterior 1/2. Disc densely punctate, punctures small, separated by less than own width; setose, setae less dense near base and along suture. Cuticle variably patterned, usually yellow with transverse, zig zag bands of dark brown spots near the base and at the apical 1/3, sometimes lacking the apical band. Epipleuron widest at humeri, narrowing at abdominal ventrite 1, grooved adjacent to abdomen. Metathoracic wings: macropterous. Prosternum: wider than long; anterior margin projecting to cover mouthparts with a chin piece; prosternal process extending past procoxae, medially with weak longitudinal carina, lateral margins carinate. Mesoventrite: strongly transverse; mesoventral process triangular, extending beyond mesocoxae; mesoventral cavity deep to receive prosternal process. Metaventrite: wider than long, dark brown to black; disc flattened at midline and strongly convex laterally; deep fossa at junction of discrimen and metakatepisternal suture. Legs: similar, except procoxa and mesocoxa globular, metacoxa very short and transverse; femur and tibia usually darker than tarsus; tibia and tarsus long and narrow, tarsus longer than tibia; tarsus usually with dense, short, pale setae; claws short, slender. Abdomen: mottled yellow-brown and dark brown, densely setose; with five ventrites, 1 shortest, 5 longest; ventrites 1-3 very convex in middle; ventrite 3 with prominent, raised, oval, medial patch of dense, coarse, golden yellow setae. Aedeagus: (Fig. 19 ) 2.5X as long as wide; phallobase narrow basally then widening apically; parameres stout, much longer than penis and enclosing it, apices with inner margins truncate; penis much narrower than a paramere, elongate, parallel-sided, broadly rounded at apex, with broad basal apophyses. Female (Figs 21-23 ) larger than male and darker. Elytra red-brown or dark brown, usually patterned with several yellow, transverse, zig zag bands; less often with yellow markings only at base. Pronotum with a small, triangular, yellow or yellow-brown subbasal spot just anterior to scutellar shield, sometimes obscure. Tarsi not densely setose. Abdominal ventrite 3 lacking a prominent, raised, medial patch of golden yellow setae. Ovipositor: (Fig. 23 ) with baculus nearly twice as long as gonocoxite; baculus almost twice as long as wide, strap-like, wider apically; each proximal gonocoxite triangular, distal gonocoxites separate basally then converging to meet apically, apices obliquely truncate; each gonostylus long and narrow, half as long as distal gonocoxite. Very similar to that of T. felix (Fig. 16 ).

Variation.

Males are smaller than females: males, 3.3-3.9 mm long, 2.0-2.6 mm wide (n = 19); females, 4.3-4.7 mm long, 2.1-3.0 mm wide (n = 7). The elytral cuticle of males is yellow, yellow-brown, or brown with dark brown patterning (Figs 18 , 20 ), while that of females is red-brown to dark brown with yellow patterning (Figs 21 , 22 ). The pronotal yellow, oblong, subbasal spot of the males is usually yellow-brown and reduced to a triangle or less in the females. The tibiae of males are more setose than those of females. Females (Fig. 21b ) lack the prominent, raised patch of golden yellow setae on abdominal ventrite 3 that is present in males (Fig. 18b ).

Egg description.

Eggs spherical, 0.2 mm diameter (n = 10); flattened on one side; chorion with tiny dimples.

Etymology.

The trivial name, cekalovici, honors the late Tomás Čekalović, who was an outstanding coleopterist, arachnologist, and field biologist from Concepción, Chile ( Urbina Burgos 2013). The name is a noun in the genitive case.

Geographic distribution.

Tychepsephus cekalovici sp. nov. is known only from Chile. Adults have been collected in Región VII (del Maule), Región VIII ( Bío Bío) (M. Elgueta, in litt.), Region XIV (Los Ríos), and Región X (Los Lagos), in both the Andean and the coastal mountain areas (Fig. 7 ). The greatest number of adults collected by the authors was at Río Colegual west of Puerto Varas (Fig. 8 ).

Habitat.

Tychepsephus cekalovici sp. nov. adults were found in habitats as described under the genus Tychepsephus (see above). Adults were collected by sweeping marginal vegetation along streams and small, shallow rivers during the austral summer (Figs 8 , 9 , 11 ).

Associated dryopoid taxa.

Elmidae : Larainae : Hydora annectans , H. lenta ; Elminae : Austrolimnius , Luchoelmis , Neoelmis sissicollis . Both T. cekalovici sp. nov. and T. felix occurred at Río Colegual.

Figures

Figure 7. Map of Chile with enlarged section showing the geographic distribution of species-verified adult Tychepsephus specimens: T. cekalovici, yellow triangles; T. felix, violet squares; both species, red circles.

Figure 20. Tychepsephus cekalovici sp. nov., male dorsal habitus showing color pattern variation a length 3.3 mm b length 3.5 mm c length 3.5 mm.

Figures 8 - 11. Tychepsephus habitat 8 Rio Colegual, T. cekalovici type locality a stream with riffle-pool morphology flowing through a mixture of forest and pasture land b streamside shrubby vegetation, adult habitat 9 Rio Contaco 10 stream at Puente El Avion 11 tributary Rio Blanco.

Figures 18, 19. Tychepsephus cekalovici sp. nov., male 18 habitus a dorsal view b ventral view; length 3.2 mm 19 aedeagus a dorsal view b lateral view c ventral view.

Figures 21 - 23. Tychepsephus cekalovici sp. nov., female 21 habitus a dorsal view b ventral view; length 4.4 mm 22 dorsal color pattern variation; length 4.3 mm 23 ovipositor, dorsal view.

Figures 13, 14. Tychepsephus felix, male 13 habitus a dorsal view b ventral view; length 5.0 mm 14 aedeagus a dorsal view b lateral view c ventral view.

Figures 15, 16. Tychepsephus felix, female 15 habitus a dorsal view b ventral view; length 4.2 mm 16 ovipositor, dorsal view.