Myrsidea troglodyti ( Denny, 1842 )

Price, Roger D., Johnson, Kevin P. & Dalgleish, Robert C., 2008, Myrsidea Waterston (Phthiraptera: Menoponidae) from wrens (Passeriformes: Troglodytidae), with descriptions of three new species, Zootaxa 1740, pp. 59-65 : 63-64

Myrsidea troglodyti ( Denny, 1842)

( Figs. 10–12 )

Menopon troglodyti Denny, 1842: 200 . Type host: " Troglodytes Europaeus" = Troglodytes troglodytes (Linnaeus, 1758) , the Winter Wren.

This species is the first and only Myrsidea to date that has been described from a member of the Troglodytidae . What is surprising is that the type series used by Denny for this description is composed only of four immatures, each mounted on its own slide which are displayed in Fig. 12 . A slide with a late third instar nymph showing evidence of the female setae developing beneath the nymphal integument bears a pencil inscription designating it as the type female. The other specimens represent two more third instars in an earlier state of development and a smaller louse, most likely a second instar. Denny does not mention the sex of these specimens and his vague description is of little value. Denny worked from specimens on cards, although his collection was mounted in Canada balsam on microscope slides sometime prior to 1937 by persons unknown. Thompson (1937) itemized the lice in the Denny collection at the British Museum (Natural History) and only listed two females of M. troglodyti from T. t. troglodytes [" T. parvulus , Wren, Britain ", on slide labels]. These slides bear the acquisition numbers (1852-98) of the Denny collection and undoubtedly represent two of the four specimens originally examined by Denny. We have examined these slides which are displayed ( Fig. 12 ).

Third instar nymph. Head with moderately developed hypopharyngeal sclerites ( Fig. 11 ). Dorsoventral metathorax and abdomen as in Fig. 10 . Metanotal margin with 10–11 setae; metasternal plate with 10 setae. All abdominal tergites of similar size. Tergal setae: I, 12–14; II–III, 13–15; IV, 14; V, 11–12; VI, 12; VII, 9– 11; VIII, 8. Postspiracular setae very long to extremely long on all segments, shortest on V. Pleurites I–VII with relatively uniform short setae, VIII with pair of slightly longer setae. Sternal setae: II, each aster with only 2 short setae, 13–15 marginal between asters, 10–11 anterior; III, 16–22; IV, 27–33; V, 34–35; VI, 32–36; VII, 15–17; VIII–IX, 13–14. Dimensions: TW, 0.54–0.56; HL, 0.35–0.37; PW, 0.36–0.38; MW, 0.52–0.59; AWIV, 0.72–0.82; TL, 1.74–1.78.

Material. 3 third instar, 1 second instar nymphs, ex T. troglodytes , all representing type series for M. troglodyti , BRITAIN, Denny Collection 1852-98. Though one slide is marked " type " and Hopkins and Clay (1952:234) indicate that the type is at the British Museum (Natural History), neither Denny nor anyone else designated a type specimen of this species. We hereby designate the third instar nymph described above as the Lectotype and return it to The Natural History Museum, London.

Remarks. While there are difficulties comparing a species represented only by immature lice with those represented by adults, the lengths of the postspiracular setae of M. troglodyti are similar to those of M. whitemani and distinct from those of the other two species described above. Also, the head dimensions of M. troglodyti are larger than any of the others, the metasternal plate has 10 setae, and there are indications of a possible significantly smaller number of tergal and sternal setae, including the very weak aster of only two setae. Most of these features for M. troglodyti point up a closer relationship to M. whitemani than to the others, but we feel the evidence supports the recognition of all as distinct taxa until a study of adults from T. troglodytes reveals otherwise.

Figures

FIGURE 12. Image of four slides of M. troglodyti, Lectotype third from left.

FIGURES 5 – 11. 5 – 9. Myrsidea bessae. 5. Female dorsoventral metathorax and abdomen. 6. Female hypopharyngeal sclerites. 7. Male dorsoventral metathorax and abdomen. 8. Male genital sac sclerite. 9. Male genitalia. 10 – 11. M. troglodyti, third instar nymph. 10. Dorsoventral metathorax and abdomen. 11. Hypopharyngeal sclerites.