Ephydrolithus jacobinensis, Amorim-Junior & Nascimento & Hamada, 2024

Amorim-Junior, Gilson P., Nascimento, Jeane M. C. & Hamada, Neusa, 2024, Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae): new species and updated distribution records from Northeast region of Brazil, Zootaxa 5443 (1), pp. 54-66 : 55-59

Ephydrolithus jacobinensis sp. nov.

( Fig. 2A–D )

Type material. Holotype male deposited at INPA, labeled: “ BRAZIL, Bahia, Miguel Calmon / Cachoeira do Jajai, Parque Sete Passagens / 11º23’35.6”S 40º32’16.3”W / 950 m a.s.l. / 25.xii.2022 —seepage habitat near the waterfall, leg. Amorim-Junior, G.P. ” . Paratypes (15): deposited at INPA: 6 male, 5 female: “ BRAZIL, Bahia, Jacobina / Cachoeira da Viúva / 11º09’28.3”S 40º29’54.9”W / 592 m a.s.l. / 20.xii.2022 —moss on seeping rocks near the waterfall, leg. Amorim-Junior, G.P. ”; deposited at MZUSP: 1 male, 2 female, same data as holotype; 1 male: “ BRAZIL, Bahia, Miguel Calmon / Cachoeira Bico do Urubu , Parque Sete Passagens / 11º24’07”S 40º32’18.7”W / 684 m a.s.l. / 26.xii.2022 —seepage habitat near the waterfall, leg. Amorim-Junior, G.P. ” .

Differential diagnosis. Ephydrolithus jacobinensis sp. nov. closely resembles Ephydrolithus ogmos Girón & Short 2019 by sharing well-defined striae. However, the new species can be easily distinguished by having striae 1–5 well-defined, punctate, each placed in a deep groove along the entire length of the elytra; punctate striae 6–10 are similar to striae 1–5 but starting at the posterior third of the elytra; in E. ogmos elytra with well-developed striae along the posterior half and reduced serial punctures. Aedeagus of E. jacobinense with parameres 0.2 × the greatest width of the median lobe, while E. ogmos has parameres 0.7 × the greatest width of the median lobe.

Description. Body length 3.3–4.0 mm (n = 16, mean = 3.93); width, 1.8–1.9 mm. Body elongate oval ( Fig. 2A ), strongly convex ( Fig. 2B ) in lateral view. General dorsal coloration dark reddish, except margins of pronotum and elytra slightly lighter, with reddish-brown tone; ventral coloration dark, except legs which are reddish-brown; tarsi and antennomeres 1–6 yellow, three terminal antennomeres of antennal club slightly darker than antennomeres 1–6. Posterior elevation of mesoventrite ( Fig. 3C ) creating prominent anterior ridge with well-defined spine. Elytra with well-defined punctate striae along deep grooves ( Fig. 3A ); striae 1–5 occurring along entire length of elytra and striae 6–10 starting at posterior third of elytra; ground punctures uniformly distributed among punctate striae. Pro-and mesofemora covered with hydrofuge pubescence along basal half; metafemora with hydrofuge pubescence along basal 2/3 of anterior margin, and with glabrous tibial grooves. Apex of fifth abdominal ventrite rounded ( Fig. 3D ). Aedeagus ( Fig. 4A ) with basal piece 0.7 × the length of parameres; parameres nearly 0.2 × the greatest width of the median lobe, with outer margins slightly sinuate; apex of parameres rounded, obliquely directed inward, each with four apical setae; apex of median lobe triangular with a slight constriction, narrowly rounded.

Female. No visible sexual dimorphism. Genitalia ( Fig. 5B ) with paraproct 0.4 × length of stylus; proctiger with fringes of setae on distal margin, broad at the base and tapering towards apex; medial region of the proctiger with apex truncate; paraproct with long seta inserted at apex; gonostylus with three apical setae, median seta at least 5 × longer than lateral ones.

Etymology. The specific epithet refers to Jacobina municipality (Bahia), in the northern portion of the Chapada Diamantina, Brazil, one of the localities where the new species was collected.

Distribution ( Fig 1 ). Northern portion of the Chapada Diamantina, Bahia state, Brazil.

Remarks ( Fig 6 ). This species was collected in a vertical seep on a rock with moss near the riverbank.

Figures

FIGURE 1. Map with geographic distribution of Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae). Gray circles represent previously described species in Bahia and Minas Gerais states. Red stars indicate the localities of Ephydrolithus dandarae sp. nov. in Ceará and Pernambuco states. Yellow stars indicate the locality of Ephydrolithus jacobinensis sp. nov. in the northern region of the Chapada Diamantina in Bahia state.

FIGURE 2. Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae), habitus, male. (A–D) Ephydrolithus jacobinensis sp. nov., holotype: (A) dorsal view; (B) lateral view; (C) ventral view; (D) frontal view. (E–H) Ephydrolithus dandarae sp. nov., holotype. (E) dorsal view; (F) lateral view; (G) ventral view; (H) frontal view. Scale bars: 1 mm.

FIGURE 3. Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae), general morphology by SEM micrographs. (A–D) Ephydrolithus jacobinensis sp. nov., paratype: (A) white arrow points to serial punctures into grooves, dorsal view, scale bar: 200 μm; (B) lateral habitus, scale bar: 1 mm; (C) mesoventrite, ventral habitus, scale bar: 100 μm; (D) white arrow points to the fifth abdominal ventrite, ventral habitus, scale bar: 100 μm. (E–H) Ephydrolithus dandarae sp. nov., holotype: (E) white arrow points to serial punctures, dorsal view, scale bar: 100 μm; (F) lateral habitus; scale bar: 500 μm; (G) mesoventrite, ventral habitus, scale bar: 50 μm; (H) white arrow points to the fifth abdominal ventrite, ventral habitus; scale bar: 50 μm.

FIGURE 5. Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae), general morphology of female genitalia. The black arrow indicates the medial region of the proctiger; the green arrow indicates the apical region of the gonostylus with inserted setae, while the red arrow indicates the seta inserted in the paraproct. (A) Ephydrolithus dandarae sp. nov., paratype. (B) Ephydrolithus jacobinensis sp. nov., paratype. Scale bars: 0.1 mm.

FIGURE 6. Habitat where Ephydrolithus Girón & Short, 2019 (Coleoptera: Hydrophilidae) can be found. (A) White arrow points to mosses on vertical cliff, stream edge. (B–C) Trails act as streams in rainy seasons, white arrow points to Ephydrolithus on rocks with water film. (D) Waterfall with vegetation on the side. (E–F) Plant roots and mosses on stream margin.

FIGURE4. EphydrolithusGirón &Short, 2019(Coleoptera:Hydrophilidae),generalmorphologyof aedeagus.(A) Ephydrolithus jacobinensis sp. nov., holotype. (B) Ephydrolithus dandarae sp. nov., holotype. Scale bars: 0.1 mm.