Notomicrus teramnus, Guimarães & Ferreira-Jr, 2019

Guimarães, Bruno A. C. & Ferreira-Jr, Nelson, 2019, Two new species and new records of Notomicrus Sharp, 1882 (Coleoptera: Noteridae) from Brazil, Zootaxa 4629 (2), pp. 263-270 : 266-267

Notomicrus teramnus sp. nov.

( Figs 2 , 3b, 3 e–f, 3i–j, 3l)

Type locality. Brazil, Minas Gerais State, Caparaó Municipality, Parque Nacional do Caparaó, Cachoeira do Rogério .

Type material. Holotype ♂. “ BRAZIL, MINAS GERAIS STATE, Caparaó Municipality, Parque Nacional do Caparaó, Cachoeira do Rogério , 24.III.2012, Jardim G.A. leg.” ( DZRJ 6541 ) . Paratype. Same data as holotype (1 ♀ / DZRJ 6543 ) .

Diagnosis. Notomicrus teramnus sp. nov. can be distinguished from other species in the genus by the following characteristics: antennae with antennomeres VI–IX shorter than wide ( Fig. 3b ); maxillary and labial last palpomere emarginated at apex, with two large sensory fields ( Figs 3i –j ); elytra with indiscernible setal punctures beside discal rows and along lateral margins ( Fig. 3l ); male anterior protarsal claw substantially wider at base than posterior one ( Fig. 3e ); median and right lateral lobes of aedeagus very distinctive ( Fig. 2 b–l).

Description. Holotype. Body outline, in dorsal view ( Fig. 2a ) slightly elongated oval, broader anteriorly and attenuated posteriorly (TL/MW = 2.00); in lateral view, dorsally weakly convex and ventrally flat.

Measurements. TL = 1.30 mm; MW = 0.65 mm; TL/MW = 2.00.

Color ( Fig. 2a ). Head dorsally dark brown and ventrally yellowish. Antennae yellowish. Pronotum yellowish. Elytra dark brown. Metasternum, outer laminae of the metacoxae and base of abdomen dark brown. Remaining of ventral surface yellowish.

Head. Head with fine microreticulation consisting of elongate cells in transverse direction. Antennae with apical antennomere elongate, length lesser than total length of head, distally subserrate, antennomeres V – X expanded, antennomeres VI–IX shorter than wide ( Fig. 3b ). Maxillary palp with apical palpomere elongate, length greater than half of total length of palp, distally attenuate, apex rounded, emarginated at apex, with two large sensory fields ( Fig. 3i ). Labial palp with apical palpomere elongate, expanded, length greater than twice the combined length of basal palpomeres, emarginated at apex, with two large sensory fields ( Fig. 3j ).

Thorax. Pronotum with fine microreticulation consisting of isodiametric cells, except along anterior margin, which are elongate. Elytra with fine weakly impressed microreticulation consisting of isodiametric cells, increasingly elongate posteriorly; indiscernible setal punctures beside discal rows and along lateral margins ( Fig. 3l ). Metasternum and noterid platform with impressed microreticulation consisting of oblong cells, increasingly elongate along suture. Noterid platform with lateral outline divergent posteriorly, with posterior margins oblique, apical lobes acutely rounded. Protarsal claws equal in length and shorter than protarsomere V; in lateral view, anterior claw substantially wider at base than posterior one ( Fig. 3e ). Mesotarsal claws equal in length and shorter than mesotarsomere V; in lateral view, anterior claw slightly wider at base than posterior one ( Fig. 3f ).

Aedeagus ( Fig. 2 b–f). Median lobe, in dorsal aspect ( Fig. 2c ), with two hooks on base ( Fig. 2g ): a smaller one, extending to right side, bending proximally, and a larger one, extending to left side, bending distally, both originating near left apodeme ( Fig. 2h ) and closing against surface of lobe; in lateral aspect ( Figs 2b, 2d ), with a dorsal projection ( Fig. 2j ) distally truncate, originating from lobe midlength, and two short ridges, in addition to the medial spermathic ridge ( Fig. 2i ), on left side ( Fig. 2d ): a curved one ( Fig. 2l ), extending from dorsal projection apex to three-fourths of lobe, and a straight one, arising from base to dorsal projection ( Fig. 2k ); apical region of median lobe gradually sharpening and culminating in a rounded and twisted apex. Left lateral lobe ( Fig. 2e ) broad and elongated, setate along dorsal margin, setae long. Right lateral lobe ( Fig. 2f ) small and oval.

Female. Protarsal and mesotarsal claws similar, without any meaningful modification.

Variation. Measurements. TL = 1.30 mm; MW = 0.62 mm; TL/MW = 2.10.

Due to the scarceness of specimens available, it is not possible to assess intraspecific variation.

Comparative notes. Notomicrus teramnus sp. nov. has a peculiar aedeagal morphology ( Fig. 2 b–f) that distinguishes this species from any other known Notomicrus . For the relative small size, the new species looks similar to N. brevicornis and N. gracilipes but is distinguished from these by the darker head, elytra ( Fig. 2a ), metasternum, outer laminae of the metacoxae and base of abdomen; by the antennae with antennomeres VI–IX shorter than wide ( Fig. 3b ); by the maxillary and labial apical palpomeres emarginated, with two large sensory fields ( Figs 3 i–j); by the elytra with indiscernible setate punctures beside discal rows and along lateral margins ( Fig. 3l ) and by the shape of male protarsal claws ( Fig. 3e ). Notomicrus teramnus sp. nov. can be distinguished from N. gracilipes also by the smaller size (TL = 1.30 mm to N. gracilipes : TL = 1.35–1.45 mm, Sharp 1882; Young 1978).

Biological note. As well as N. petrareptans Baca & Short, 2018 , N. teramnus sp. nov. was collected in hygropetric habitat; however, as few specimens were obtained, it isn’t possible to verify that N. teramnus sp. nov. is, as N. petrareptans , strictly associated with these habitats. The specimens were collected in fillets of water on rocks, near the margin of a stream, along with specimens of Torridincolidae .

Etymology. The specific name is the Greek adjective “ teramnus ”, meaning tender. This is in reference to its smooth elytra and delicate appearance.

Geographic distribution. So far N. teramnus sp. nov. is known only from the Brazilian state of Minas Gerais.

Figures

FIGURE 2. Notomicrus teramnus sp. nov. a) dorsal view, b) median lobe of aedeagus, right lateral aspect, c) same, dorsal aspect, d) same, left lateral aspect, e) right lateral lobe of aedeagus, f) left lateral lobe of aedeagus, g) dorsobasal hooks, h) left apodeme, i) medial spermathic ridge, j) dorsal projection, k) left side proximal ridge, l) left side distal ridge.

FIGURE 3. Notomicrus appendages and dorsal view. a–b) left antenna; c, e) male left protarsal claw, anterior aspect; d, f) male left mesotarsal claw, anterior aspect; g, i) left maxillary palp, ventral aspect; h, j) left labial palp, ventral aspect; k–l) dorsal view, depicting distribution of setate punctuation; m) dorsal view. a, c–d, g–h, k) Notomicrus meizon sp. nov., b, e–f, i–j, l) Notomicrus teramnus sp. nov., m) Notomicrus traili, specimen from Amazonas.