Cylindrogaster cavernicola Kamimura, sp. n.

Kamimura, Yoshitaka & Ferreira, Rodrigo L., 2017, Earwigs from Brazilian caves, with notes on the taxonomic and nomenclatural problems of the Dermaptera (Insecta), ZooKeys 713, pp. 25-52 : 28-30

Cylindrogaster cavernicola Kamimura, sp. n. Figs 1-7

Material examined.

Holotype ♂, 'Gruta Apertar | da Hora | Jandaíra RN <= Rio Grande do Norte >', ' ISLA | 21101', ' 15.ii.2010 | Ferreira, R.L. leg. ', ' HOLOTYPE (male) | Cylindrogaster cavernicola | sp. n. | Det. Y. Kamimura 2017'.

Diagnosis.

Cylindrogaster cavernicola sp. n. is a median-sized species with a slender abdomen and simple forceps. This species differs from all other species of Cylindrogaster with the combination of the following characters: the well-developed tegmina; pronotum slightly longer than broad; parameres with blunt apices; and short but weakly sinuated virgae.

Description.

Male (holotype: Fig. 1 ). Length of body (without forceps): 11 mm. Length of forceps: 1.4 mm. Head width: 1.5 mm. Pronotum width: 1.0 mm. Pronotum length: 1.3 mm.

The body color of the holotype seems to have been bleached by preservation in ethanol. Body color uniformly pale amber but abdomen darker. Body, including forceps, sparsely pubescent.

Head (Fig. 2 ) slightly longer than broad, widest in the region of the eyes; frons tumid, occiput depressed; transverse and median suture not conspicuous but visible; hind margin strongly emarginated in middle; post-ocular carina well developed, almost straight, running from middle of the internal margin of the eyes to the hind margin of the head; lateral margins of post-ocular region bordered with strong bristles. Antennae broken, 10 (right) and 15 (left) segments remaining; first segment stout, expanded apically, length almost the same as the distance between antennal bases; second segment short, quadrate; third segment expanding apically, widest width almost the same as the length; fourth segment almost quadrate; fifth segment almost quadrate (left side) to 1.5 times longer than the width (right side); remaining segments gradually lengthening. Eyes prominent, slightly shorter than post-ocular length. Pronotum (Fig. 2 ) slightly longer than broad; anterior margin almost straight; sides parallel; hind margin broadly rounded; median sulcus distinct; prozona weakly raised. Tegmina (Fig. 3 ) well developed, 1.5 times wider than pronotum, about twice as long as pronotum; broad triangular scutellum visible. Wings (Fig. 3 ) well-developed. Legs long, slender; hind tarsi with first segment 2.5 times longer than third, second segment about half as long as third, claw with small arolium. Abdomen long, cylindrical; segments eight and nine slightly expanded. Penultimate (= 9th) sternite (Fig. 4 ) slender, with shallow concave sides; caudal margin forming a more or less semicircular lobe. Ultimate (= 10th) tergite (Fig. 5 ) moderately inflated, oval; caudal margin shallow concave between forceps. Forceps (Fig. 5 ) robust and short, almost straight, pubescent especially on inner margins, tapering and weakly curving inward apically, base of inner margin with small tooth. Genitalia (Figs 6 , 7 ); virga short and sinuated; parameres (= external parameres) short and broad, rounded, with small triangular sclerotized tubercle and sparse short hairs at apex.

Female. Unknown.

Remarks.

The subfamily Cylindrogastrinae consists of six species belonging to the Neotropical genus Cylindrogaster ( Hincks 1955; Steinmann 1986, 1989b). Their external appearance resembles those of the Diplatyinae species or Diplatyidae sensu stricto (Table 1 ). However, males of Cylindrogaster spp., including C. cavernicola sp. n. described here, have one gonopore on each of the paired virgae, which is a heavily sclerotized process containing the terminal part of the ejaculatory duct, whereas male diplatyids (and haplodiplatyids) have a pair of bifurcated virgae ( Hincks 1955; Steinmann 1989a).

This new species is allied to C. gracilis Stal, 1855, which was recorded from Brazil (and also possibly from Peru). However, the virga is entirely straight and the parameres are much wider than the length in the latter species (Fig. 11 ). Another Brazilian species, C. thoracicus Dohrn, 1863, can be distinguished from C. cavernicola sp. n. by its much longer virgae (Fig. 10 ) and pronotum (Fig. 8 ).

Key to the known Cylindrogaster species (males only)

1	Tegmina reduced to small lateral flaps. Ultimate tergite strongly inflated. Forceps well developed, so-called macrolabic	Cylindrogaster bicyclurus
-	Tegmina not reduced, well developed, normal. Ultimate tergite not or little inflated. Forceps, so-called microlabic	2
2	Parameres of genitalia triangular with pointed apex	3
-	Parameres of genitalia trapezoid or oval, broader than long, with blunt apex	4
3	Virga short but sinuated, with a characteristic projection at middle	Cylindrogaster sahlbergi
-	Virga short, curved but not sinuated, without a characteristic projection at the middle	Cylindrogaster yepezi
4	Pronotum (excluding anterior zone tapering to head) apparently longer than broad (Fig. 8 )	5
-	Pronotum (excluding anterior zone tapering to head) almost quadrate or slightly longer than broad (Figs 2 , 9 )	6
5	Pronotum (excluding anterior tapering region) more than 1.5 times longer than broad. Virga straight, very short, almost half as long as penis lobe	Cylindrogaster velox
-	Pronotum (excluding anterior tapering region) less than 1.5 times longer than broad. Virga sinuated, relatively long (Fig. 10 )	Cylindrogaster thoracicus
6	Virga simple, straight, almost as long as penis lobe (Fig. 11 )	Cylindrogaster gracilis
-	Virga very short, almost half as long as penis lobe, but weakly sinuated (Figs 6 , 7 )	Cylindrogaster cavernicola Kamimura, sp. n.

Etymology.

The species epithet refers to the cave-dwelling habit of this new species, although it is presently unknown whether it is a troglobite.

Distribution.

Rio Grande do Norte, Brazil.

Association with caves.

The specimen of Cylindrogaster cavernicola Kamimura, sp. n. was collected near the entrance of a cave associated with limestone rocks from the Jandaíra formation (Upper Cretaceous) in northern Rio Grande do Norte state. The caves in this region are predominantly shallow, most of which present several connections with the epigean environment (usually vertical cracks in the limestone outcrops). Accordingly, many caves in the area are strongly influenced by the external environment. Even so, given the extremely dry external environment, the caves represent a more suitable habitat for many animal species, presenting more stable temperatures and higher humidity than the epigean habitat. Furthermore, although the macro-caves are more influenced by the epigean environment, they are connected to huge systems of meso-caves, comprising small passages that are much more stable.

Figures

Figures 1 - 11. 1 - 7 Cylindrogaster cavernicola Kamimura, sp. n. (male, holotype): habitus (1), head and thorax (2), tegmina and wings (3), penultimate sternite (4), ultimate tergite and forceps (5), and genitalia (6, 7) 8, 10 Cylindrogaster thoracicus (MM 3637; collected from Itatiaia, Brazil; det. W. D. Hincks): head and thorax (8), and genitalia (10) 9, 11 Cylindrogaster gracilis: head and thorax (9: MM 3677; collected from Itatiaia, Brazil; det. W. D. Hincks), and genitalia (11: MM 3565; collected from Minas Gerais, Brazil; det. W. D. Hincks). Scale bars 3 mm for Fig. 1; 0.5 mm for Figs 2 - 6, 8 - 11; 200? m for Fig. 7.