35.047 Bryotropha affinis (Dark Moss-moth)
ws: 9.5-12.5mm; May-Aug; common in S.England more local further north
Bryotropha affinis §1
ID: External Features - Labial palp S3 longer than S2, S2 with conspicuous furrowed brush; ws 9-13mm; 1st discal stigma distal to plical stigma; fw ground colour blackish; plical stigma distal border with a cluster of pale yellowish scales; costal and tornal patches yellowish (often) fused to form a narrow fascia; whole fw with pale irroration. Some examples have a paler ochreous or brown ground colour in which case the markings are more prominent than in other species of similar size.
B.umbrosella is most similar - it has pale white rather than yellowish cluster beyond plical stigma, costal and tornal patches; costal and tornal patches seldom fused to form a fascia and ground colour without pale irroration.
B.similis lacks conspicuous pale scales beyond the plical stigma, but may appear otherwise very similar.
Male Genitalia: Aedeagus with whip-like apex; sacculus present; (base of gnathos and surface of vinculum without microtrichia); gnathos slender - at least 3x as long as wide, not markedly thickened at middle and with an abrupt curve.
The key in MBGBI4.2 also refers to the number of spikes on the thornshield (up to 40 in B.affinis) but this feature seems to require higher powered microscopy than is available to me - as does the presence or absence of microtrichia at base of gnathos. The 4 species that show microtrichia are easily excluded as 2 of them (galbanella and boreella) lack a furrowed brush on labial palp S2 and the the other two (terrella and desertella) have a very distinctive gnathos.
Female Genitalia: Signum consisting of a plate with strong spines on the corners; (microtrichia on S8 needle-shaped); lamella post-vaginalis without lobes; signum shorter than apophyses anteriores, trapezoidal and with two strong spines at posterior end.
In practice differences in the male gnathos and the female signum seem small and may be difficult to determine with certainty, but use of a combination of genital and external features should lead to correct ID. Specimens 1,2 show good external features for B.affinis but identification has not been confirmed by genital examination. Specimen 3 has been reidentified as B.similis and removed from this page. Specimen 4 appears to be B.affinis on external features but the signum is rectangular suggesting it may be B.similis. The signum of B.affinis should be more triangular - I await further material. Specimen 5 lacks pale scales beyond the plical stigma but shows a gnathos that appears typical of B.affinis.
B.umbrosella is most similar - it has pale white rather than yellowish cluster beyond plical stigma, costal and tornal patches; costal and tornal patches seldom fused to form a fascia and ground colour without pale irroration.
B.similis lacks conspicuous pale scales beyond the plical stigma, but may appear otherwise very similar.
Male Genitalia: Aedeagus with whip-like apex; sacculus present; (base of gnathos and surface of vinculum without microtrichia); gnathos slender - at least 3x as long as wide, not markedly thickened at middle and with an abrupt curve.
The key in MBGBI4.2 also refers to the number of spikes on the thornshield (up to 40 in B.affinis) but this feature seems to require higher powered microscopy than is available to me - as does the presence or absence of microtrichia at base of gnathos. The 4 species that show microtrichia are easily excluded as 2 of them (galbanella and boreella) lack a furrowed brush on labial palp S2 and the the other two (terrella and desertella) have a very distinctive gnathos.
Female Genitalia: Signum consisting of a plate with strong spines on the corners; (microtrichia on S8 needle-shaped); lamella post-vaginalis without lobes; signum shorter than apophyses anteriores, trapezoidal and with two strong spines at posterior end.
In practice differences in the male gnathos and the female signum seem small and may be difficult to determine with certainty, but use of a combination of genital and external features should lead to correct ID. Specimens 1,2 show good external features for B.affinis but identification has not been confirmed by genital examination. Specimen 3 has been reidentified as B.similis and removed from this page. Specimen 4 appears to be B.affinis on external features but the signum is rectangular suggesting it may be B.similis. The signum of B.affinis should be more triangular - I await further material. Specimen 5 lacks pale scales beyond the plical stigma but shows a gnathos that appears typical of B.affinis.
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§1 Westcliff-on-sea, Essex; 11/07/2007; fw: 5.6mm
§2 Westcliff-on-sea, Essex; 05/06/2008; fw: 5.0mm §3 Misidentification §4 Westcliff-on-sea, Essex; 20/07/2010; female; fw: 5.5mm §5 Nethybridge, Inverness-shire; 15/07/2011; male; fw: 5.2mm §6 Westcliff-on-sea, Essex; 15/08/2014; female; fw 5.0mm §7 Westcliff-on-sea, Essex; 16/07/2014; female; fw: 5.9mm §8 Bampton Grange, Cumbria; 01/08/2017; male; fw 5.5mm §9 Bampton Grange, Cumbria; 03/08/2017; female; fw 5.7mm All images © Chris Lewis |
§10 Bampton Grange, Cumbria; 14/06/2017
§11 Bampton Grange, Cumbria; 06/07/2017; male; fw 5.1mm §12 Westcliff-on-sea, Essex; 16/07/2018; female; fw 5.0mm §13 Westcliff-on-sea, Essex; 14/06/2020 §14 ??; 2020; female |
Page published October 2011 | §6 (female genitalia only) added 31/08/2014 | §7 added 21/12/2014 | §8&9 added 05/01/2018 |
§10 added 07/04/2018 | §11 added 11/04/2018 | §12 added 27/04/2019 | §13 added 22/01/2021 | §14 added 08/04/2021
§10 added 07/04/2018 | §11 added 11/04/2018 | §12 added 27/04/2019 | §13 added 22/01/2021 | §14 added 08/04/2021
