Sapromyzosoma halidayi, Shatalkin, 2000

Ebejer, Martin J., 2019, Taxonomic notes on West Palaearctic species of Lauxania Latreille, Sapromyza Fallén, Calliopum Strand and Minettia Robineau-Desvoidy, with a description of a new species of Minettia (Diptera, Acalyptrata: Lauxaniidae) from Morocco, Zootaxa 4543 (1), pp. 37-51 : 38-43

The Sapromyza halidayi Shatalkin— S. tuberculosa Becker problem

Becker (1895) described S. tuberculosa from the French Pyrenees and in 1907 he described Sapromyza maculipes from a male taken in Algeria stating that this was the same species as his specimen from Riva on Lake Garda, Italy. Papp (1978), examining this male specimen from Italy, considered it to be a synonym of S. sordida Haliday. He noted the detailed diagnostic characters of both male and female specimens given by Collin (1948) who had examined Haliday’s type (a female) and other specimens of both sexes of S. sordida in Haliday’s collection. Papp (1984) also examined two male specimens collected in Dorset, England and housed in the Natural History Museum, London and identified as S. sordida Haliday by Dr J.C. Deeming. Papp’s opinion was that these are not conspecific with S. maculipes (which earlier he had synonymized with sordida ). However, he did not offer an opinion as to which species they belonged, yet his brief description of these specimens does fit with S. sordida Haliday. Because of this, the impression is given that S. sordida and S. tuberculosa are different species. In March 2018, I examined these two specimens, including a female specimen from the same series, in order to establish their true identity. In my opinion these are conspecific with s ordida.

Shatalkin (2000) proposed the new name S. halidayi for S. sordida Haliday, 1833 , described from Ireland, because the name S. sordida Haliday was preoccupied by a species described in the same genus from the West Indies by Wiedemann in 1830, but which is now in Neogriphoneura Malloch, 1924 , where it was designated the type species of the genus. Shatalkin also raised the possibility that S. tuberculosa Becker, 1907 , is a synonym of S. halidayi . Merz (2002) aware of this problem, suggested that perhaps the northern species is S. halidayi and the southern species is S. tuberculosa , but he did not elaborate further. A synonymy was not formally proposed or rejected by either author. I examined several specimens from Britain, France (Pyrenees), Spain (Balearic Islands), Sicily, Portugal and Morocco and found them to be identical in external characters and in the postabdominal features of both sexes to Haliday’s species. I sent photographs of the male and female terminalia of this species ( Figs 1–3 ) to Sven Marotske and Jenny Pohl (Museum fur Naturkunde, Berlin). They informed me that “the female is very similar to Becker’s holotype, which is also a female”. In my opinion, this is one species and according to article 23.3.5 of the Code for Zoological Nomenclature (2000) the name tuberculosa and not halidayi should be used for this species.

The issue is further complicated by the generic position of tuberculosa . Some genera of Lauxaniidae can be difficult to delineate on a worldwide basis. This is exemplified by the case of Calliopum Strand, 1928 . The key to genera in the Manual of Nearctic Diptera ( Shewell 1987) separates Calliopum by the presence of fine hairs dorsally on the anepimeron, 0+3 dorsocentral setae, face mostly polished and either flat or (more usually) convex, and dark shiny ground colour of body. This suite of characters does not completely apply to the west Palaearctic species. None have setulae on the anepimeron, at least two species are not dark and most have a degree of polliniosity. In the key to the genera of Lauxaniidae in the Manual of Palaearctic Diptera (Papp & Shatalkin 1989) , the main characters separating this genus consist of a convex face with a transverse depression, an elongate antenna with the scape shorter than the pedicel and 0+3 dorsocentral setae. This suite of characters reliably separates out the species of Calliopum in this zoogeographical region. Characters such as degree of pollinosity on sclerites or the ground colour may be helpful but they cannot be considered valid generic characters. There are black or yellow species, with little or with extensive pollinosity within both Sapromyza, sensu lato, and Calliopum . There are additional characters that may be more useful to help separate Calliopum from Sapromyza, at least as far as the West Palaearctic species are concerned. Collin (1948) drew attention to the mid frontal stripe in his key to genera, making the point of this being distinct and narrow in Calliopum .

With this problem in mind, I examined seven species of Calliopum [aeneum (Fallén, 1820); elisae (Meigen, 1826) ; geniculatum (Fabricius, 1805) ; hispanicum (Mik, 1881) ; oosterbroeki Shatalkin, 2000; simillimum (Collin, 1923) ; splendidum Papp, 1978] and 24 species of Sapromyza [albiceps (Fallén, 1820); apicalis Loew, 1847; basalis Zetterstedt, 1847; bisigillata Rondani, 1868; drahamensis Villeneuve, 1921; gozmanyi Papp, 1981 ; hermonensis Yarom,1990; hyalinata (Meigen, 1826); intonsa Loew, 1847; intonsina Yarom, 1990; israelis (Yarom, 1990); laevatrispina Carles-Tolrá, 1992; lazlopappi Merz, 2007; obscuripennis Loew, 1847 ; obsoleta Fallén, 1820 ; opaca Becker, 1895; palpella Rondani, 1868; parallela Carles-Tolrá, 1992; quadricincta Becker, 1895 ; quadripunctata (Linnaeus, 1767); sexpunctata Meigen, 1826; tuberculosa Becker, 1895 ; undulata Merz, 2007; unizona Hendel, 1908].

The most important and easily appreciated characters to separate these two genera are in the structure of the head. The frons in all groups of Sapromyza is flat whereas in Calliopum the orbits are raised above the plane of the rest of the frons and they are broad. At approximately the junction of the anterior third of the frons with the middle third there is a transverse depression in Calliopum , such that the plane of the anterior third is at a small angle to the plane of the rest of the frons. This is best seen in profile. The mid frontal stripe is generally easily seen when the frons is viewed from certain angles. It is almost parallel-sided in Calliopum but narrowing toward the lunule in Sapromyza. The face in Sapromyza is flat or very slightly concave when viewed in profile whereas in Calliopum this is convex to a greater or lesser extent. In the lower part of the face, approximately where the lower third meets the middle third, there is a shallow transverse groove, more pronounced at the sides, in Calliopum but no such transverse facial division in Sapromyza. This groove lies a little above the junction of the face with the clypeus and care must be taken not to confuse the two. The degree of pollinosity (anywhere on the body, not just on the head) or otherwise is not a reliable feature to separate these two genera although it is true that most species of Calliopum have more extensive shiny areas on the face and frons than do most species of Sapromyza. However, in both genera there can be significant intraspecific variablity of this character. The frons is distinctly setulose in Sapromyza but bare or with very few and minute setulae in Calliopum . The scutellum is flat or nearly so in Sapromyza but never so in Calliopum where it is distinctly and smoothly convex in its transverse and longitudinal axis.

The characters present in various combinations in species of Sapromyza versus Calliopum are tabulated below and illustrated in Figs 10–30 .

On the basis of the above interpretation of characters S. tuberculosa would fit much better in the genus Calliopum . There are clear transverse divisions of the frons and face, the latter with shiny lower lateral corners, and not to be confused with the division between the face and the clypeus, which junction lies ventral to the true facial division. The orbital plates are raised, broad and incompletely pollinose. The mid frontal vitta is broad and more or less parallel-sided. The terminalia do not appear to give clear distinguishing ground-plan characters that help to separate these two genera. For example, C. geniculatum has the male terminalia resembling those of Minettia , whereas the male terminalia of C. tuberculosum resemble those of C. elisae . Indeed, this problem was also recognised for the genera Calliopum and Lauxania where there appear to be two similar character states of the terminalia across both genera ( Perusse & Wheeler 2000). However, this was a study of Nearctic species whereas above I already noted some morphological differences between the Palaearctic and Nearctic Lauxania and Calliopum as given in the respective identification keys.

Species of Sapromyza have very diverse ground plans of the terminalia. Detailed study of these might help in the separation of species groups, subgenera or even in establishing new genera. However, caution is required here as synapomorphies in terminalia can be difficult to establish. This suggests that future phylogenetic work to address relationships between these three genera and among species within each genus should include at least species from the whole Holarctic Region to represent also the diverse species groups. This work would require the combined approach of morphological and molecular investigation.

The proposed changes in nomenclature and synonymy thus read:

Calliopum tuberculosum ( Becker, 1895) comb. nov.

Sapromyza didyma Pandellé, 1902

- junior synonym of S. tuberculosa Becker, 1895 established by Papp (1981)

Sapromyza inculta Pandellé, 1902

- junior synonym of S. tuberculosa Becker, 1895 established by Papp (1981)

Sapromyza maculipes Becker, 1907: 383

- junior synonym of S. sordida Haliday, 1833 established by Papp (1978)

Sapromyza sordida Haliday, 1833

- primary homonym of S. sordida, Wiedemann, 1830: 456 .

Sapromyza halidayi Shatalkin, 2000

- new name proposed because of primary homonymy with S. sordida, Wiedemann, 1830 ;

- here proposed as a junior synonym of S. tuberculosa Becker, 1895

The terminalia of C. tuberculosum were not illustrated. Figures of these in both sexes are provided here ( Figs

4–9).

Figures

FIGURES 1–3. Calliopum tuberculosum,1) male terminalia in situ, ventral, 2) same, ventral oblique, 3) female abdomen in situ, lateral.

FIGURES 10–13. Lauxaniidae heads, lateral, 10) Calliopum simillimum, 11) C. tuberculosum, 12) C. hispanicum, 13) Sapromyza obsoleta.

FIGURES 14–16. Calliopum frons, dorsal, with the orbital plate and border of ocellar triangle (with mesofrons) outlined in white lines on the left except 15 where demarcations are self-evident. 14) C. simillimum, 15) C. hispanicum, 16) C. tuberculosum.

FIGURES 17–20. Sapromyza frons, dorsal, with the orbital plate and border of ocellar triangle (with mesofrons) outlined in white lines on the left. 17) S. gozmanyi, 18) S. quadricincta, 19) S. obscuripennis, 20) S. obsoleta.

FIGURES 21–24. Sapromyza face, frontal, 21) S. gozmanyi, 22) S. quadricincta, 23) S. obscuripennis, 24) S. obsoleta.

FIGURES 25–27. Calliopum face, frontal, 25) C. simillimum, 26) C. hispanicum, 27) C. tuberculosum.

FIGURES 28–30. Scutellum, dorsal, 28) Sapromyza obscuripennis, 29) S. gozmani, 30) Calliopum tuberculosum.

FIGURES 4–6. Calliopum tuberculosum, male terminalia, 4) lateral, 5) same, posterior, 6) same ventral. Scale bar = 0.65 mm

FIGURES 7–9. Calliopum tuberculosum, female terminalia, 7) lateral, 8) same, posterior, 9) same, dorsal. Scale bar = 0.65 mm