Typhlocharis tetramera Pérez-González & Zaballos, 2013

Pérez-González, Sergio & Zaballos, Juan P., 2013, Tarsal tetramery and extreme size reduction in Anillini (Coleoptera, Carabidae, Trechinae): the case of Typhlocharis Dieck, 1869; description of three new species and definition of a new intra-generic species group, Zootaxa 3682 (2), pp. 249-269 : 258-261

Typhlocharis tetramera Pérez-González & Zaballos new species

( Figs 5–6 )

Type series. Holotype, 3, SPAIN: Badajoz, Mérida (5 km NE), 12- 12-2012, 256 m (N 38º 56’, W 06º 17’), J.P. Zaballos, S. Pérez & S. Ghannem leg. (Coll. J.P. Zaballos, UCM). Paratypes: 1 Ƥ same data as holotype; 2 ƤƤ same locality as holotype, 6-2-2013, J.P. Zaballos & S. Pérez leg.; 14 3, 21ƤƤ same locality as holotype, 27-2- 2013, J.P. Zaballos & S. Pérez leg. (38 ex. Coll. J.P. Zaballos, UCM).

Diagnosis. Very small, anophtalmous, endogean beetle, with narrow and sub-rectangular body covered by microreticulate integument and scattered pubescence. Vertex with pars stridens. Antennae with ventral sensilla coeloconica only in antennomere 6th. Gula partially fused to cephalic capsule. Elytra subtly serrated in lateral margins, almost imperceptible in posterior region. Apical margin with one pair of denticles, associated to 7th stria. Umbilicate series with five setae (4+1). Tarsal formula: 4-4-4. Metatarsal ungues are sexually dimorphic: gaugeshaped, with section in “D” in females; pointed, with subcylindrical section in males. Aedeagus as in Fig. 6 A,B, with "parenthesis-shaped" endophallic sclerite. Female genitalia with club shaped gonocoxites, as in Fig 6 C.

Description. Length of holotype: 1.03 mm; length of paratypes: 0.93–1.07 mm (males), 0.93–1.10 mm (females) ( Fig. 5 ).

Head: sligthly wider (0.20–0.25 mm) than long (0.20–0.21mm). Labrum slightly notched. Antennae as in T. scrofa sp.n. but ventral sensilla coeloconica only in antennomere 6th (absent in ant. 5th). Labium with pointy epilobes and a blunt, low middle tooth. Ligula with prominent middle lobe and long paraglossae. Other cephalic characters and cephalic chaetotaxy as described for T. scrofa sp.n.

Pronotum: sub-trapezoidal to rectangular, clearly longer (0.25–0.31 mm) than wide (0.21–0.25 mm), narrowed in posterior region. Very narrow medial hiatus (width less than two adjacent intersetae spaces). Disc flattened, with faint medial line and a pair of lateral sulci. Rest of characters and chaetotaxy are the same as for T. scrofa sp.n., except a pattern [(m)-m-l-l / l-l-m-(m)] of setae parallel to posterior margin. Proepisternal suture faint, almost imperceptible. Other prosternal characters as for T. scrofa sp.n.

Elytra: approximately two times longer (0.47–0.59 mm) than wide (0.22–0.26 mm), sub-parallel. Apical margin with only one pair of denticles, associated to the 7th stria. Chaetotaxy: umbilicate series with anterior group of four setae and posterior group of one seta ( Fig. 5 ). One pair of scutellar setae; no apparent discal setae.

Legs: similar in both sexes. Wide intermetacoxal space. Metacoxae with blunt triangular "flap". Rounded, smoothly acuminate metatrochanters, slightly angular pro- and metafemora, metatibiae with dilated distal region. Tarsi with four tarsomeres (tarsal formula 4-4-4). Metatarsal ungues are sexually dimorphic: blunt and flat gaugeshaped with cross section in “D” in females; typical pointed claws, with subcylindrical cross section in males.

Abdomen: as described for T. scrofa sp.n., but females with a pair of slight ventral foveae in the first ventrite. Last ventrite with lateral teeth, pattern of six to seven pairs of setae in posterior margin, sexually dimorphic: l-s-s-ls-s / s-l-s-l-s-s-l ( Fig. 5 ).

Aedeagus: sickle-shaped median lobe (length: 0.14 mm) and broad, rounded apex, not bend in dorsal view ( Fig. 6 A). Endophallus with short, thin "parenthesis-shaped" sclerites. Parameres subtriangular, with two mediumsized apical setae ( Fig. 6 B).

Female genitalia: club-shaped, robust gonocoxites with two apical setae: one large, one very small (absent or lost in the majority of specimens) ( Fig. 6 C). No lateral setae, but scattered pores. Gonoduct with a thinner proximal region (diameter: 0.002 mm) and thicker distal region (diameter: 0.006 mm). Ovoid to subcylindrical spermatheca (length: 0.019 mm, width: 0.010 mm). Spermathecal gland tubular to conical (length: 0.027 mm), slender and sclerotized in distal region ( Fig. 6 C).

Habitat. Open prairie-pasture lands with large amphibolite or quartzite boulders (Precambrian), crossed by a river. Clayey soil, dark-brown to reddish, with high humidity but not saturated. Vegetation composed mainly by broom ( Retama sp. Raf.), asphodels ( Asphodelus sp. L.), larus ( Arisarum sp. Mill.), low thorny bushweeds ( Flueggea tinctoria (L.) G.L. Webbster) and herbaceous Brassicaceae . Soil samples were taken under deeply embedded boulders. It coexists with Typhlocharis elenae .

Etymology. The name is derived from the legs all possessing four tarsomeres.

Variability. The intraspecific variation observed within the type series affects to the width of hiatus (narrow to very narrow), shape of labrum (from slightly notched to substraight in a few individuals), shape of clypeus (from straight to subtly curved), proportions of pronotum, marking of denticles in pronotum (very faint to absent), degree of acumination in metatrochanters (more rounded than average in four of the specimens) or subtle variations in chaetotaxy of labium, basilar or last ventrite. There are three specimens with abnormalities in the elytral apex: asymmetries and damage.

Affinities. The new species has a strong resemblance to T. scrofa sp.n., (most likely its closest relative) sharing important diagnostic features such as a 4+1 umbilicate series or the shape of aedeagus and gonocoxites, as well as the diffuse gula and four tarsomere condition. Size range and many morphological details are also coincident.

However, T. tetramera sp.n. can be differentiated from T. scrofa sp.n. by a lower middle tooth in labium, ventral sensilla coeloconica only in antenommere 6th (observed only in this species), a faint or diffuse prosternal suture as occurs in T. quadridentata ( Pérez-González & Zaballos 2012) , the lack of discal setae, the absence of parasutural teeth in the apex of elytra, a wider intermetacoxal space, larger and more acuminated metatrochanters, or the shape of the spermateca, subovoid to subcylindrical instead of subsphaeric, similar to that of T. crespoi ( Serrano & Aguiar 2008) . Also, the presence of sexual dimorphism in the shape of metatarsal ungues is known exclusively for T. tetramera sp.n.

It should be noted that, separately, some of these characters are known to have intraspecific variation, as occurs with the parasutural teeth of the elytral apex in T. elenae ( Serrano & Aguiar 2002) but others have not intraspecific variation, like the presence/absence of discal setae, and the whole group of differences between T. scrofa sp.n. and T. tetramera sp.n. is maintained in all the studied specimens.

Figures

FIGURE 5. Typhlocharis tetramera sp. n. habitus: ventral (left half: male, right half: female) and dorsal (male) views. Abdomen not shown in dorsal view for a clearer view of elytral apex.

FIGURE 6. Typhlocharis tetramera sp. n. (A, B) Aedeagus: A) median lobe (dorsal view); B) median lobe and parameres (lateral view). C) Female genitalia (ventral view).