Prosimulium tomosvaryi

Prosimulium tomosvaryi is a geographically widespread morphospecies, ranging across ecoregions from Britain to Azerbaijan, and on that basis it is a good candidate for cryptic species. It has been characterized chromosomally in the centre (Basrur, 1959), southwestern (Morocco; Adler & Belqat, 2001) and, now, south-eastern (Armenia) portions of its distribution.

We were able to associate the name tomosvaryi with a cytological entity from the type locality of P. tomosvaryi, an unknown site in the old kingdom of Württemberg (now Baden-Württemberg). Topotypical larvae are chromosomally similar to those from the Czech Republic studied by Basrur (1959), except that they lack the X-linked IS-15 and tiny Y-linked IS-16 inversions and are apparently fixed for IIL-3, which is polymorphic (frequency = 0.19) in the Czech Republic. Our Furtwangen and Feldberg collections are also about 25 km from the type locality (Freiburg) of Prosimulium nigripes, the name of which was synonymized with P. tomosvaryi long ago, a decision now supported chromosomally.

Although Armenian populations differ in floating inversions from those in Europe, they have the same sex

hc, extra heterochromatin.

†Includes three females and five males with mermithid nematodes.

‡Sex chromosomes could not be determined because the sample included only females.

§One male larva with Y 2, the other with undifferentiated sex chromosomes (X 0 Y 0).

¶Includes one female with mermithid nematode.

††Includes one female with probable new species of microsporidium.

‡‡Heterozygous for primary nucleolar organizer (N.O.) expression.

§§* = Linked to the Y chromosome (Y 2 = IIIS-2 + differential banding in CIII region).

¶¶Precise breakpoints of a small, knot-like inversion in sections 87–88 of one female could not be resolved.

†††** = X 0 Y 1 (differential banding in CIII region).

s, standard, i, inverted.

†Not in Hardy−Weinberg equilibrium (χ 2 = 11.85, df = 1, P <0.001).

‡Not in Hardy−Weinberg equilibrium (χ 2 = 4.44, df = 1, P <0.05).

chromosome as our material from the type locality in Germany. The single female larva from Turkey is most similar to Armenian larvae, particularly in sharing 84hb, although it lacks IIS-11; males were not available for comparison. An X chromosome based on the IS-14 inversion – absent in Morocco – thus links Armenian, European, and Turkish populations.

We are inclined to view populations from Armenia, Europe, and Turkey as a single species under the name P. tomosvaryi, united by IS-14. IIL-3, which is fixed in some European populations but floating in others, and IIS-11, which is predominantly inverted but, nonetheless, exists as a rare polymorphism in Armenia, might reflect inversion clines or local adaptations. Under this conservative scenario, the name Prosimulium duodecimfiliatum Rubtsov is a legitimate synonym; the type locality of P. duodecimfiliatum in Dilijan, Armenia, is within 20 km of our collection sites. Collections from intervening areas could test our hypothesis of a single chromosomally polymorphic species.

Moroccan populations of P. tomosvaryi are chromosomally more remote, differing from Armenian populations by three fixed, or nearly fixed, inversions hb, heteroband; hc, extra heterochromatin.

§Not in Hardy−Weinberg equilibrium (χ 2 = 6.08, df = 1, P <0.05).

Fixed rearrangements are italicized and polymorphic rearrangements are in standard type.

†Includes one female with microsporidium similar to Weiseria laurenti.

‡* = sex linked: X 1 = IS-14; Y 0 = standard.

§In Hardy−Weinberg equilibrium (ss = 13, si = 7, ii = 5; where s, standard and i, inverted; χ 2 = 3.54, df = 1, P > 0.05).

hb, heteroband.

Fixed rearrangements are italicized and polymorphic rearrangements are in standard type.

(IL-9 and IIIL-16 of Adler & Belqat, 2001, and IIS-11) and by lacking any shared autosomal or sex-linked polymorphisms. Given a distance of roughly 4400 km between the southern extremes of the distribution, the significance of the chromosomal differences cannot be evaluated. If verified as a distinct species, Moroccan populations would require a new name.