Bryotropha |
Generic features: Antenna with pecten reduced to a single bristle (strong and persistent) (sometimes absent in B.boreella and B.galbanella);
Ocelli present; Labial palp S2 with a conspicuous furrowed brush on underside; S3 as long as or longer than S2 (furrowed brush absent and S3 shorter than S2 in B.boreella and B.galbanella); Forewing elongate, tapering from middle; V7&8 stalked ending at costa; plical and 2 discal spots; costal patch opposite or slightly proximal to tornal spot - these may be fused to form a fascia; Hindwing as broad as forewing, subtrapezoidal, apex pointed; V6&7 stalked, V3&4 connate or short-stalked.
Ocelli present; Labial palp S2 with a conspicuous furrowed brush on underside; S3 as long as or longer than S2 (furrowed brush absent and S3 shorter than S2 in B.boreella and B.galbanella); Forewing elongate, tapering from middle; V7&8 stalked ending at costa; plical and 2 discal spots; costal patch opposite or slightly proximal to tornal spot - these may be fused to form a fascia; Hindwing as broad as forewing, subtrapezoidal, apex pointed; V6&7 stalked, V3&4 connate or short-stalked.
Identification: Most species are variable and require genital examination to confirm ID.
Only B.domestica has sufficiently prominent forewing markings for confident identification to species (and is excluded from the tables below).
B.boreella and B.galbanella lack a conspicuous furrowed brush on the underside of S2 of the labial palps and these two may be separable on size.
Larger specimens (ws: 14-17mm) with a conspicuous furrowed brush are likely to be B.terrella, B.politella or B.desertella; but a smaller size does not rule out the latter two of these species (and such small specimens cannot be identified using the key in MBGBI4.2).
Only B.domestica has sufficiently prominent forewing markings for confident identification to species (and is excluded from the tables below).
B.boreella and B.galbanella lack a conspicuous furrowed brush on the underside of S2 of the labial palps and these two may be separable on size.
Larger specimens (ws: 14-17mm) with a conspicuous furrowed brush are likely to be B.terrella, B.politella or B.desertella; but a smaller size does not rule out the latter two of these species (and such small specimens cannot be identified using the key in MBGBI4.2).
Keys to species of Bryotropha
B.domestica can be identified by its prominent forewing stigmata and does not feature in the tables below
Male genitalia: The aedeagus has a curved or coiled apex (whip-like) in all except B.domestica. The uncus is a hood with a broad apex in all except B.domestica, in which it narrows to pointed apex. Sacculi are present in all except B.domestica and B.politella, and they are relatively inconspicuous in B.terrella. Distinguishing the remaining species is largely based on the shape of the gnathos in lateral view. The key in MBGBI4.2 uses the presence of microtrichia, at the base of the gnathos and over the surface of the vinculum, to segregate B.terrella/desertella/galbanella/boreella; and the shape of the thornshield (a pair of folds covering the base of the gnathos laterally) and presence of minute spikes in the thornshield to segregate some other species - but I have not found these features easy to determine, and have devised a key that does not use them. All species, except B.politella, have socii with a varying number spines of varying length and strength but I am uncertain how consistent the differences between the species are, and this feature is not used in the keys.
|
MALES |
Gnathos |
||
Labial palp S2 without a conspicuous furrowed brush |
slightly sinuous |
ws>15mm |
B.galbanella |
straight |
ws<15mm |
B.boreella |
|
Sacculus absent |
B.politella |
||
Sacculus present |
S-shaped apex |
B.terrella |
|
triangular with a very broad base |
B.desertella |
||
90° bend halfway |
B.dryadella |
||
acute internal angle at junction of proximal ⅓ and distal ⅔ |
forewing with pale irroration |
B.affinis |
|
forewing without pale irroration |
B.similis |
||
broad-based, tapering |
apex of gnathos weakly sclerotised |
B.senectella |
|
apex of gnathos strongly sclerotised |
B.basaltinella |
||
evenly curved and of even width |
B.umbrosella |
Bryotropha domestica shares the absence of sacculi with B.politella and is unique in having a pointed uncus and the aedeagus without a whip-like apex
Bryotropha politella can be identified by the combination of absent sacculi and the aedeagus with a whip-like apex; it also has a highly characteristic gnathos with a strongly sclerotised apical 'nail'.
|
Bryotropha terrella has a broad gnathos narrowing to a strongly sclerotised S-shaped apex
|
Bryotropha desertella has a triangular gnathos with a very broad base
(No material)
(No material)
Bryotropha boreella has a narrow fairly straight gnathos
The gnathos is quite similar to that of B.affinis and B.similis. |
Bryotropha galbanella has a narrow sinuous gnathos
|
Bryotropha dryadella has a gnathos with a 90° bend halfway
(No material) |
Bryotropha basaltinella has a broad-based tapering gnathos with a strongly sclerotised apex
(No material) |
Bryotropha senectella has a broad-based tapering gnathos with a weakly sclerotised apex
|
Bryotropha affinis has a gnathos with an acute internal angle at the junction of the proximal ⅓ and distal ⅔. This appearance is very similar to B.similis, from which it is best distinguished by the presence of pale irroration of the forewing (see below). Externally it is most similar to B.umbrosella which has a more smoothly curved gnathos.
|
Bryotropha umbrosella has an evenly curved gnathos of even width
|
Bryotropha similis has a gnathos with an acute internal angle at the junction of the proximal ⅓ and distal ⅔. This appearance is very similar to B.affinis, from which it is best distinguished by the absence of pale irroration of the forewing (see below).
|
Female genitalia: Differences between the species occur in the shape of the posterior margin of the ventral surface of S8, a ventral midline groove in which the ostium is placed, and in the form and shape of the signum. There are two forms of signum: a pleated plate with two transverse ridges (in B.domestica/politella/terrella/desertella/boreella/galbanella) and a flat more or less rectangular plate with a strong spine in each corner (in B.dryadella/basaltinella/senectella/affinis/umbrosella/similis). B.terrella is unique in having a large triangular (in lateral view) sclerotised antrum, there being no significant discernible antrum in any other species.
FEMALES |
|||
Labial palp S2 without a conspicuous furrowed brush |
ventral groove margins sinuate |
B.galbanella |
|
ventral groove margins gradually separating towards anterior margin of S8 |
B.boreella |
||
Signum a pleated plate |
large triangular antrum |
B.terrella |
|
posterior margin of S8 deeply excavate to >½ its length |
signum quadrate, shorter than anterior apophyses |
B.politella |
|
signum elongate, as long as anterior apophyses |
B.desertella |
||
Signum a flat plate with a strong spine at each corner |
signum elongate, length 2x width (as long as anterior apophyses) |
B.similis |
|
signum broader at posterior end |
B.affinis |
||
signum length ~= width |
Posterior margin of S8 straight apart from a shallow ventral midline emargination |
B.dryadella |
|
Posterior margin of S8 peaked dorsally and gradually recedes ventrally |
B.basaltinella |
||
signum oval, length > width |
signum with broad margins |
B.senectella |
|
signum with narrow margins |
B.umbrosella |
Bryotropha domestica has a very elongate pleated plate signum
|
Bryotropha politella has a quadrate pleated plate signum and a deeply excavate posterior margin of the ventral plate of S8
|
Bryotropha terrella is unique in having a large triangular sclerotised antrum; it also shows a sclerotised emarginate posterior border to the dorsal surface of S8 (seen as a dark mark in the lateral view below)
|
Bryotropha desertella has an elongate pleated plate signum and a deeply excavate posterior margin of the ventral plate of S8
|
Bryotropha boreella has a midline ventral groove running the whole length of S 8 with sinuate margins.
(No material) |
Bryotropha galbanella has a midline ventral groove running the whole length of S 8 with margins that gradually separate towards the anterior border.
(No material) |
Bryotropha dryadella has a quadrate flat plate signum; it is probably best separated from B.basaltinella by the posterior margin of S8 which is straight, apart from a small midline ventral excision,
(No material) |
Bryotropha basaltinella has a quadrate flat plate signum; it is probably best separated from B.dryadella by the posterior margin of S8 which is peaked dorsally and gradually recedes from the lateral border to the midline ventrally.
(No material) |
Bryotropha senectella has an oval flat plat signum with broad margins (ie if a line is drawn from the base of an anterior spine to a posterior spine on the same side, there is a broad extent of signum outside this line)
|
Bryotropha affinis has the signum broader and with stronger spines at the posterior end
|
Page published 27/09/2018 | B.similis ♀ added 10/12/2023