Leptocera gongylotheca Buck, 2009

Buck, Matthias & Marshall, Stephen A., 2009, Revision of New World Leptocera Olivier (Diptera, Sphaeroceridae), Zootaxa 2039 (1), pp. 1-139 : 46

Leptocera gongylotheca Buck , new species

( Figs. 69–75 )

Description. Indistinguishable from L. argentinica sp.n. except for the shape of the female spermathecae ( Fig. 74 ): Spermatheca perfectly spherical, lacking narrow, ridged, subcylindrical basal section; entire surface (except very base) bumpy. Male terminalia as in Figs. 69–72 , female terminalia as in Figs. 73–75 .

Type material. Holotype ♀ and 13 ♂♂, 12 ♀♀ paratypes ( DEBU): ARGENTINA, Prov. Salta, Santa Rosa de Tastil 100 km W Salta, 3,000 m, 21.ii.1992, very dry along creek, S.A. Marshall. Note: The identity of all except one female was confirmed through dissection. Males cannot be distinguished from L. argentinica sp.n. (males unassociated with females are listed under L. argentinica sp.n.).

Etymology. The species name is a noun in apposition and refers to the diagnostic, spherical spermathecae (Gr. gongylos: round, spherical).

Distribution. Only known from the type locality in northern Argentina (Salta Province) where it occurs together with its sibling species L. argentinica sp.n.

Discussion. We were uncertain at first how to interpret the puzzling case of spermathecal variation presented by L. argentinica / gongylotheca sp.n. species pair. It seems clear that the different spermathecal shapes do not represent different developmental stages (e.g., pre- or post-insemination) since there are no intermediate stages, and the spermathecal base of the elongate type (here described as L. argentinica sp.n.) is just as sclerotized and inflexible as the remainder of the spermathecal body. We decided against interpreting the different shapes as a case of structural polymorphism (unknown so far in spermathecae of Sphaeroceridae ) because in the L. caenosa group there is another example of the exact same type of variation (spherical vs. elongate spermathecae), which in this case is undoubtedly due to specific distinctness ( L. erythrocera and L. sphaerotheca sp.n.). In this species pair the spermathecal differences are correlated with one external character (length of posteroapical bristles of mid tibia) as well as ecological differences ( L. sphaerotheca sp.n. occurs at higher altitudes than L. erythrocera ; see Discussion under L. sphaerotheca sp.n.).

Figures

FIGURES 69–75. Leptocera gongylotheca sp.n. (Argentina). Male terminalia (phallus and postgonites omitted): (69) lateral; (70) posterior; (71) ventral; (72) sternite 5. Female terminalia: (73) dorsal; (74) spermathecae; (75) ventral. cp—finger-like process of cercus, da—desclerotized area, proc—process at base of posterior section of surstylus, sa—shining area of tergite 7.