Philopterus pseudhirundo, Gustafsson & Najer & Zou & Bush, 2022

Gustafsson, Daniel R., Najer, Tomas, Zou, Fasheng & Bush, Sarah E., 2022, New species of Philopterus Nitzsch, 1818 (Ischnocera: Philopteridae), with notes on Cypseloecus Conci, 1941, European Journal of Taxonomy 790 (1), pp. 1-52 : 38-42

Philopterus pseudhirundo sp. nov.

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Figs 43–48 ; Tables 2–4 , 6

Diagnosis

Philopterus pseudohirundo sp. nov. belongs to the same group as other species of Philopterus known from hirundinid hosts (see Table 7 ). Of these, only P. excisus Nitzsch, 1818 (ex Delichon urbicum (Linnaeus, 1758)), and P. microsomaticus Tandan, 1955 (ex Hirundo rustica rustica Linnaeus, 1758), were illustrated and described in sufficient detail for an adequate comparison to be made. Characters supporting this relationship include the strongly bilobed hyaline margin ( Fig. 45 ), the somewhat splayed distal male genitalia ( Figs 46–47 ), and the general shape of the head ( Fig. 45 ).

Philopterus pseudhirundo sp. nov. can be separated from P. excisus by the following characters (see Tandan (1955) and Clay & Hopkins (1960) for partial illustrations and redescriptions of P. excisus ): preantennal area longer and narrower in P. pseudhirundo sp. nov. than in P. excisus ; abdominal segments IV–V in male P. excisus with 6–8 pleural setae on each side, but with only 4–5 pleural setae on each side in P. pseudhirundo sp. nov. ( Fig. 43 ); male sternal plate V interrupted medianly in P. excisus , but medianly continuous in P. pseudhirundo sp. nov.; distal margin of male genitalia (ignoring gonopore) convex in P. excisus , but concave in P. pseudhirundo sp. nov. ( Figs 46–47 ); mesosome with wide angular lateral margins in P. excisus , but with slender rounded lateral margins in P. pseudhirundo sp. nov. ( Fig. 47 ); parameres reach about as far distally as mesosome in P. excisus , but much father distally in P. pseudhirundo sp. nov. ( Figs 46–47 ); anterior end of mesosome in P. excisus different in shape from that of P. pseudhirundo sp. nov. ( Fig. 46 ).

Philopterus pseudhirundo sp. nov. can be separated from P. microsomaticus by the following characters: male tergopleurite II with 4–7 (typically 6) setae on each side in P. microsomaticus , but with 8 setae on each side in P. pseudhirundo sp. nov. ( Fig. 43 ); male genitalia with concave distal margin (ignoring gonopore) in P. pseudhirundo sp. nov. ( Figs 46–47 ), but with protruding distal end in P. microsomaticus ; mesosome protruding distally to parameres in P. microsomaticus , but not in P. pseudhirundo sp. nov. ( Figs 46–47 ); anterior margin of dorsal mesosome with blunt angle in P. microsomaticus , but with acute angle in P. pseudhirundo sp. nov. ( Fig. 46 ).

The sclerotized median section of the hyaline margin was not mentioned by either Tandan (1955) or Clay & Hopkins (1960); however, in specimens of P. microsomaticus we have examined, the sclerotized median section is evident. Presumably, this character also occurs in other species of Philopterus from hirundinid hosts, but this has to be verified.

Etymology

The specific name is derived from the type host genus.

Material examined

Holotype NO LOCALITY • ♂; South Africa?; 5 Jun. 1950; [F.] Zumpt leg.; ex Pseudhirundo griseopyga (as Hirundo griseopygia); “ S-125 , I.N. 1373/26 ”; MFN.

Paratype NO LOCALITY • 1 ♀; same collection data as for holotype; MFN .

Type host

Pseudhirundo griseopyga Sundevall, 1850 – gray-rumped swallow (Hirundinidae).

Description

Head shape and chaetotaxy as in Fig. 45 , preantennal area narrow. Hyaline margin wide, extending laterally beyond marginal carina, deeply concave medianly; weak sclerotization in mid-section. Dorsal anterior plate elongated, shape as in Fig. 45 . Ventral anterior plate small, anterior margin deeply concave. Coni small, blunt, directed laterally. Gular plate short, broad. Thoracic and abdominal segments as in Figs 43–44 . Measurements as in Table 6 .

Male

Thoracic and abdominal chaetotaxy as in Fig. 43 and Tables 2–4 . Medianly continuous sternal plates present on segments V–VI, lateral accessory plates present on segments II–IV. Basal apodeme slender ( Figs 46–47 ), widening markedly in distal end. Mesosome as in Fig. 47 , with 3 microsetae on each side. Parameres short, blunt ( Figs 46–47 ), with pst1–2 apical.

Female

Leg II on both sides of the only examined female missing or distorted, not illustrated. Thoracic and abdominal chaetotaxy as in Fig. 44 and Tables 2–4 . Central sternal plates absent, lateral accessory plates present on segments III–VI. Subgenital plate and vulval margin as in Fig. 48 ; chaetotaxy as in Fig. 48 and Table 3 . Lateral sclerotizations of vulval area extended to vulval margin. Subvulval plates elongated triangular.

Remarks

The collection locality is not given on the slide, but the host is restricted to Africa ( Turner & Rose 1994), and Zumpt’s collections are otherwise mainly from South Africa ( Ledger 1980).

Conci (1941) described the genus Cypseloecus for the Philopterus species on swallows (Hirundinidae) and swifts (“Cypseli” = Apodiformes); however no Philopterus complex lice occur on swifts, and the name is thus a misnomer. This erroneous host range may be a result of earlier authors believing Pediculus hirundinis Schrank, 1803 (= Philopterus hirundinis (Schrank, 1803)) to be the same as Pediculus hirundinis Linnaeus, 1758 (= Dennyus hirundinis (Linnaeus, 1758)) . Clay & Hopkins (1950, 1960) showed that these names refer to different species, of which only the latter occurs on swifts. To date, nine species of Philopterus have been described from swallows ( Table 7 ), all of which fall into the “ Cypseloecus ” group; if the genus Cypseloecus Conci, 1941 is resurrected, all the species listed here should be included in that genus based on their descriptions and published illustrations.

Hopkins & Clay (1952), Price et al. (2003), and Mey (2004) considered Cypseloecus inseparable from Philopterus . Mey (2004) stated that the only notable character of this group is the bilobed state of the hyaline margin. We here describe a new species of Philopterus from a swallow, P. pseudhirundo sp. nov. This species exhibits several characteristics that seem to indicate that the Philopterus from swallows may be more different from Philopterus s. str. than previously believed. However, the relationships within Philopterus s. lat. are poorly known, and it is not clear which morphological characters are useful for the delimitation of groups within Philopterus s. lat.

The most distinctive character of the “ Cypseloecus ” group is the preantennal area. Compared to most other species of Philopterus , the preantennal area is narrow and elongated in “ Cypseloecus ,” with a deeply concave frons and distinctly bilobed hyaline margin. As can be seen in the species of Philopterus described here, the shape of the preantennal area and the hyaline margin vary greatly between different species in the genus (cf., e.g., Figs 3 , 9 , 39 ). In most of the Philopterus from corvid hosts (including the type species, P. ocellatus ; see Price & Hellenthal 1998), the frons is more or less flat, convex, or only slightly concave. Even in species of Philopterus where the frons is concave (e.g., Fig. 3 ), the lateral parts of the hyaline margin do not form distinct, narrow lobes as in “ Cypseloecus ”.

In P. pseudhirundo sp. nov., the central part of the hyaline margin is sclerotized ( Fig. 45 ), which makes the head superficially resemble that of many species of Philopteroides Mey, 2004 . However, this character is not illustrated or mentioned in the descriptions of any other species in “ Cypseloecus .” We have examined some specimens of P. microsomaticus at the Museum of Natural History, University of Wroclaw, Poland. These all have a median sclerotization similar to that of P. pseudhirundo sp. nov. Presumably, this sclerotization occurs in other species of “ Cypseloecus ” as well, but we have not examined any of them. No other species of Philopterus from other host families have this sclerotization, but it occurs in many other genera in the Philopterus complex ( Mey 2004).

The male genitalia are also distinct in “ Cypseloecus ,” with a rather flat distal margin of the mesosome and somewhat flaring parameres ( Figs 45–46 ). This is unlike the genitalia of most other species described here, which have a more rounded distal margin of the mesosome and more convergent parameres (e.g., Figs 22–23 ). However, the type species of Philopterus , and most other species from corvid hosts, have genitalia that are more similar to those of “ Cypseloecus ” than to most of the other species described here. Moreover, some species of Philopterus on non-hirundinid hosts have genitalia that are intermediate between the two types (e.g., P. stansburyensis sp. nov.; Figs 34–35 ). Too little is known about the more detailed structure of the mesosome and other parts of the genitalia in the Philopterus complex to make a more detailed comparison.

In our opinion, these differences are not sufficient, based on our current knowledge, to recognize Cypseloecus as a distinct genus within the Philopterus complex, but are perhaps sufficient to recognize it as a subgenus within Philopterus . Potentially, at least three groups are involved: Philopterus s. str. from corvid hosts, with simple hyaline margin, typically short preantennal areas, and splayed male genitalia; “ Cypseloecus ” from hirundinid hosts, with a deeply bilobed hyaline margin with median sclerotization, slender and elongated preantennal area, and splayed genitalia; and Philopterus s. lat. (=? Docophorulus Eichler, 1944) from other hosts, with an intermediate hyaline margin, typically short preantennal areas, and convergent parameres. Most likely, the morphological variation in this latter group is sufficient to recognize further subgeneric or generic groups, some of which may not be recognizable based on published illustrations and descriptions. We do not propose any taxonomic changes at the genus level here, but note that a more thorough revision of Philopterus is needed. Such a revision should, in our opinion, include a consideration of resurrecting Cypseloecus as at least a subgenus within Philopterus .

Figures

Figs 43–44. Philopterus pseudhirundo sp. nov. ex Pseudhirundo griseopyga Sundevall, 1850. 43. Male habitus, dorsal and ventral views. 44. Female habitus, dorsal and ventral views.

Figs 45–48. Philopterus pseudhirundo sp. nov. ex Pseudhirundo griseopyga Sundevall, 1850. 45. Male head, dorsal and ventral views. 46. Male genitalia, dorsal view. 47. Male genitalia, ventral view. 48. Female subgenital plate, vulval margin, and subvulval plates, ventral view.

Figs 3–6. Philopterus hebes sp. nov. ex Chloropsis aurifrons inornata Kloss, 1918. 3. Male head, dorsal and ventral views. 4. Male genitalia, dorsal view. 5. Male genitalia, ventral view. 6. Female subgenital plate, vulval margin, and subvulval plates, ventral view. Abbreviations: ads = anterior dorsal seta; as1–3 = anterior setae 1–3; avs1–3 = anterior ventral setae 1–3; dsms = dorsal submarginal seta; mds = mandibular seta; mts1–5 = marginal temporal setae 1–5; os = ocular seta; pas = preantennal seta; pcs = preconal seta; pos = preocular seta; pts = posttemporal seta; s1–4 = sensilla 1–4; vsms1–2 = ventral submarginal setae 1–2.

Figs 9–12. Philopterus micropunctatus sp. nov. ex Anthus hodgsoni Richmond, 1907. 9. Male head, dorsal and ventral views. 10. Male genitalia, dorsal view. 11. Male genitalia, ventral view. 12. Female subgenital plate, vulval margin, and subvulval plates, ventral view.

Figs 39–42. Philopterus coriaceus sp. nov. ex Molothrus oryzivorus oryzivorus (Gmelin, 1788). 39. Male head, dorsal and ventral views. 40. Male genitalia, dorsal view. 41. Male genitalia, ventral view. 42. Female subgenital plate, vulval margin, and subvulval plates, ventral view.

Figs 21–24. Philopterus sinensis sp. nov. ex Hemipus picatus capitalis (Horsfield, 1840). 21. Male head, dorsal and ventral views. 22. Male genitalia, dorsal view. 23. Male genitalia, ventral view. 24. Female subgenital plate, vulval margin, and subvulval plates, ventral view.

Figs 33–36. Philopterus stansburyensis sp. nov. ex Pheucticus melanocephalus melanocephalus (Swainson, 1827). 33. Male head, dorsal and ventral views. 34. Male genitalia, dorsal view. 35. Male genitalia, ventral view. 36. Female subgenital plate, vulval margin, and subvulval plates, ventral view.