Myrsidea stenodesma (Carriker)

Price, Roger D., Hellenthal, Ronald A. & Dalgleish, Robert C., 2005, The genus Myrsidea Waterston (Phthiraptera: Menoponidae) from tyrant­flycatchers (Passeriformes: Tyrannidae), with descriptions of 13 new species, Zootaxa 1048, pp. 1-20: 5-6

publication ID 10.5281/zenodo.169922

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Myrsidea stenodesma (Carriker)


Myrsidea stenodesma (Carriker)  ( Fig. 3View FIGURES 1 – 8. 1 – 2)

Menopon stenodesmum Carriker 1903: 184  . Type host: Empidonax atriceps Salvin, Black  –capped Flycatcher.

Female. Metanotum and dorsal abdomen as in Fig. 3View FIGURES 1 – 8. 1 – 2. Metanotum with 15 marginal setae. Tergites I –III enlarged, with II –VI having slight medioposterior convexity and VII –VIII unmodified. Tergal setae: I, 30; II, 40; III, 33; IV –V, 35–36; VI, 39; VII, 30; VIII, 20. Postspiracular setae with some missing or broken, but those on II and VII –VIII apparently very long, much shorter than on I and III –VI. Sternal setae: II, each aster with 4 setae, other setae obscured; III, 28; IV –V, 32–34; VI, 27; VII, 14; VIII –IX of subgenital plate, 21. Anus with 31 dorsal fringe setae, 34 ventral. Dimensions: TW, 0.45; HL & PW, 0.30; PSL, 0.10; MW, 0.45; MSL, 0.15; AWIV, 0.60; ANW, 0.19; TL, 1.50.

Male. Metanotum with obscured marginal setae. Tergal setae: I, 28; II –VI, 35–37; VII, 32; VIII, 24. Sternal setae: II, each aster with 4 setae, 33 other setae; III –VI, 30–35; VII, 18; VIII, obscured. Genital sac sclerite obscured. Dimensions: TW, 0.42; HL & PW, 0.28; PSL, 0.10; MW, 0.35; MSL, 0.14; AWIV, 0.44; GL, 0.41; TL, 1.26.

Material. Female holotype, male allotype of Menopon stenodesmum  , ex E. atriceps  , COSTA RICA.

Remarks. Even with the extremely poor condition of the two type specimens that Carriker (1903) used for the description of this species, the large number of tergal and/or sternal setae for both sexes readily separates it from all other tyrannid Myrsidea  except for M. magnidens  . Both sexes of M. stenodesma  , with smaller dimensions and fewer abdominal sternal setae, are easily separated from M. magnidens  . Carriker (1903) provided a description for the female and figured only that sex, with no mention of the male specimen in his type series; hence, that female is the holotype. Strangely, the male specimen carries the NMNH holotype number on the back of the slide. Since both sexes provide the same excellent separation from other tyrannid Myrsidea  , the sex of the holotype is of little significance.

By modern standards, Carriker was not a very good technician, even taking into consideration the primitive facilities available to him. Many specimens in his collection were attributed to the wrong host. Lice, especially menoponids, readily move from one host to another as dead birds cool when placed together in a collecting bag. Cross­contamination also may have occurred on the preparation table. In the absence of additional louse specimens, Carriker’s host determinations are best treated with caution. It is ironic, given the scathing rebuke of Stafford (1943) in Carriker (1955), that Carriker’s own methods appear to be suspect.


Smithsonian Institution, National Museum of Natural History














Myrsidea stenodesma (Carriker)

Price, Roger D., Hellenthal, Ronald A. & Dalgleish, Robert C. 2005

Menopon stenodesmum

Carriker 1903: 184