Depressaria saharae Gaston & Vives ssp. tabelli Buchner

Buchner, Peter, Corley, Martin & Junnilainen, Jari, 2017, Three new species and one new subspecies of Depressariinae (Lepidoptera) from Europe, ZooKeys 684, pp. 119-154 : 136-142

Depressaria saharae Gaston & Vives ssp. tabelli Buchner ssp. n.

Type locality.

Spain, Canary Islands, Tenerife, Guimar.

Holotype.

♂, Spain, Canary Islands, Tenerife, Guimar, 6.iii. Bupleurum aciphyllum [ Bupleurum salicifolium ssp. aciphyllum ], ex. 16.iv.1907, Wlsm. 99748 | Walsingham Collection 1910-427 | B.M. ♂ Genitalia Slide No. 23304, NHMUK010305296, coll. NHMUK.

Paratypes.

1 ♀, Spain, Canary Islands, Tenerife, Guimar, La Ladera, 800 m, 23.iv.1998, GP DEEUR 2634, DNA-barcode id TLMF Lep 17692 (658 bp., BOLD:ADC8281), leg. & coll. K. Larsen,; 1 ♀, Tenerife, Los Gigantes, 100 m, 8-11.i.2008, GP DEEUR 2807, DNA-barcode id TLMF Lep 17711 (658 bp., BOLD:ADC8281), leg. & coll. K. Larsen.

Other material examined.

Depressaria saharae ssp. saharae . 1 ♂, Spain, Granada, Sierra Nevada, 2430 m, 37°6.23'N; 3°23.84'W, 3.vii.2015, J. Tabell leg., GP ♂ 5480 J. Tabell, DEEUR 4024, DNA barcode id. TLMF Lep 19164 (658 bp., BOLD:ACF8051); 1 ♂, same collection data, without barcode; 2 ♂♂, Teruel, Albarracin, Val de Vecar, 1100 m, 3.x.2015, leg. J. Viehmann, coll. W. Schmitz; 1 ♂, Sr. de Albarracin, Sr. Alta, 1750m, 25.vi.2016, leg. J. Viehmann, coll. W. Schmitz; 3 ♂♂, Teruel, Albarracin. 6 km env. 1.x.2008, GP DEEUR 1000 & 1005, leg. & coll. L. Srnka, 1 of them (GP DEEUR 1000) with DNA barcode id. TLMF Lep 07068 (584 bp., BOLD:ACF8051)

Introductory note. It may be considered unusual to give a detailed description of the nominate subspecies before the description of a new subspecies, but in this case the original Spanish description is not detailed enough to serve as the basis for a comparison of the two subspecies. The original description is completely without information on genetic data and has little on relationships of the new species.It is therefore necessary to include such information on the nominate subspecies in this investigation.

Diagnosis.

The wing pattern of both subspecies of D. saharae belongs to one of the basic patterns in the genus Depressaria which can also be found e.g. in D. ultimella Stainton, 1849 and D. daucella (Denis & Schiffermüller, 1775), with which this species was confused by Walsingham (published by him as Depressaria apiella ( Hübner, 1796)). A situation which is often found in Depressaria is a combination of high intraspecific variability and near identical basic wing patterns used by several species, which makes it very difficult to determine specimens externally. When intraspecific variability is larger than the mean difference between the species, identification may become impossible. On the other hand, most species of Depressaria have distinctive genitalia in both sexes. This is the case in D. saharae , where diagnosis must be based on genitalia: see relevant paragraphs below.

Description.

Depressaria saharae ssp. saharae specimens (only males) from mainland Spain (Figs 43-47): Wingspan 18-23 mm. Head greyish brown, tips of the scales markedly paler than the rest. Labial palp second segment with long, forward projecting scales which are dark grey with a narrow whitish distal margin, third segment medium grey with flesh-coloured tinge, only at base with some blackish scales. Antenna with scape blackish, flagellum blackish on dorsal side and medium yellowish grey on ventral side. Thorax and tegulae medium greyish brown, thorax with 3 dark longitudinal streaks, one in the middle and one at each side. Forewing ground colour grey, with distinct blackish longitudinal streaks, especially in outer one-third; whitish scales are interspersed in low numbers over the whole surface, also forming an acute angled transverse line at about two-thirds, angle about 50°, and a longitudinal, somewhat interrupted line in the middle from about one-fifth to one-half; in older specimens the patterns formed by the whitish scales soon become invisible, but the longitudinal blackish streaks remain visible even in rather worn specimens; cilia dark grey, without distinct contrast from wings. Hindwing moderately translucent at base, becoming increasingly opaque toward distal part, medium greyish brown, veins darker; cilia concolorous with wings, basal one-third markedly darker than the rest in fresh specimens. Legs and abdomen without distinct patterns, covered with a mixture of light grey and blackish scales.

Depressaria saharae ssp. tabelli ssp. n. (Figs 48-52): Wingspan 22-24 mm. Head warm yellowish brown, tips of the scales only slightly paler than the rest. Labial palp second segment with long, forward projecting scales which are dark warm brown with a narrow whitish distal margin, third segment yellowish at the very tip, rest of distal half predominatly black, basal half with varying proportions of blackish and pale scales. Antenna as in nominate ssp. Thorax and tegulae warm medium brown, thorax without black longitudinal streaks, only a slightly darker shadow may be visible. The most striking differences are colour and patterns of forewings: ground colour warm medium brown in costal half, becoming darker in dorsal half, but without sharp borderline between these areas, longitudinal streaks reduced, much less prominent than in nominate ssp., in central part of costal half almost completely absent; interspersed whitish scales and acute angled transverse line as in nominate ssp., cilia following the general tendency more warm brown, no remarkable difference in hindwings, legs and abdomen.

No gender-associated differences could be found in the specimens from Canary Islands.

For comparison, D. bupleurella (Fig. 54), D. daucella (Fig. 55) and two forms of D. ultimella (Figs 56-57) are shown.

Male genitalia. Male genitalia of D. saharae (Figs 58-59) are really similar only to those of D. bupleurella Heinemann, 1870. The most distinctive difference is the width of the excavation in the costa of valva: narrow (less than half of the basal diameter of the bulges at each side of the excavation) in D. bupleurella (Fig. 60), wide (about equalling the basal diameter of these bulges) in D. saharae . Apart from the species pair D. bupleurella / saharae , the genitalia of D. radiella (Goeze, 1789) show some similarity, but with differences in many details; see comparison in Figs 58-61.

Female genitalia. Female genitalia (Figs 62-63 + 66) are also most similar to D. bupleurella (Figs 64 + 67) with nearly the same shape of ostium and an expansion in the middle of the long and narrow ductus bursae. The best feature to separate the species is the shape of the expansion: an asymmetrical swelling without longitudinal streaks in D. saharae ssp. tabelli but spindle-shaped with several longitudinal sclerotisations in D. bupleurella . D. radiella is also figured for comparison (Figs 65 + 68). Females of the nominate ssp. are unknown so far.

Molecular data.

Data of barcoded specimens. TLMF Lep 19164 (658 bp., ♂, Spain, Granada, Sierra Nevada, 2430 m, 37°6.23'N; 3°23.84'W, 3.vii.2015, J. Tabell leg., GP ♂ 5480 J. Tabell); TLMF Lep 07068 (584 bp., ♂, Spain, Teruel, Albarracin. 6 km env, 1.x.2008, 40°49.5'N; 3°2.22'W, leg. & coll. L. Srnka, gen. prep. DEEUR 1000); TLMF Lep 17692 (658 bp., ♀, Spain, Tenerife, Guimar, La Ladera, 800 m, 28°18'N; 16°25'W, 23.iv.1998, leg. & coll. K. Larsen, gen. prep. DEEUR 2634); TLMF Lep 17711 (658 bp., ♀, Spain, Tenerife, Los Gigantes, 100 m, 28°17'N; 16°51'W, 8-11.i.2008, leg. & coll. K. Larsen, gen. prep. DEEUR 2807).

Neighbour-joining analysis (Fig. 69) shows that D. saharae is a very isolated species with no obvious nearest neighbour. Depressaria bupleurella (BOLD:ABA1485; TLMF Lep 04843) shares a node in our NJ tree (Fig. 29), but at ~6.08-6.8% p-distance. Intraspecific variability, based on present knowledge, 0% within D. saharae ssp. saharae , 0% within D. saharae ssp. tabelli ssp.n and 2.01% between the two ssp.

Maximum Likelihood analysis (Fig. 70) shows in general the same situation. Following the conclusion of D. bupleurella as evolutionary neighbour based on genitalia patterns (see remarks below under Related species), this is not a surprise.

Related species.

Based on male genitalia, D. saharae belongs to the pastinacella group (Hannemann, 1953), named after D. pastinacella (Duponchel, 1838), now valid as D. radiella (Goeze, 1783), which is characterised by the presence of a basal process of sacculus (clavus) and the absence or near absence of a distal process of sacculus (cuiller). Within this group, genitalia of both sexes clearly show D. bupleurella as closest species. Neighbour Joining tree and Maximum Likelihood analysis correspond with this estimation. The close relatedness of D. saharae and D. bupleurella is also supported by biology with both species (so far only known from ssp. tabelli ) feeding on Bupleurum .

Etymology.

The subspecies name, a noun in the genitive case, honours Jukka Tabell, the Finnish lepidopterologist, who collected D. saharae - at this time still an undescribed species - in 2015 from the Spanish mainland, and sent specimens to Peter Buchner for study. They were essential to understanding this species and led to a search for females, which were found in collections from the Canary Islands and which are here treated as a separate subspecies.

Distribution.

So far known only from Spain: Canary Islands (Tenerife).

Bionomics.

Walsingham reared one moth from larvae collected on Bupleurum aciphyllum ( Bupleurum salicifolium ssp. aciphyllum (Webb & Berthel.) Sunding & G. Kunkel) from Canary Islands, Tenerife, Guimar. This plant is an endemic species of Macaronesia. The food-plant of D. saharae ssp. saharae is unknown, but is likely to be another species of Bupleurum .

Remarks.

The first encounter with male genitalia of D. saharae was a simple drawing in literature: Klimesch (1985) reports on a letter from Klaus Sattler regarding Walsingham’s bred male from Tenerife which Walsingham had referred to D. apiella : “…. According to Dr. Sattler, NHMUK London, this specimen belongs to a species near D. bupleurella or to a form of D. bupleurella . Dissection showed differences in costa of valva and in cuiller. It must be left to a later revision of this group to decide on the final status" [translated from German]. Some males from Teruel, dissected by P. Buchner, showed this distinctive genitalia feature also. DNA barcoding supported the view that it was not a form of D. bupleurella , but a distinct species. As at this stage females were unknown, it remained undescribed.

In the large collection of Knud Larson, two females from Tenerife were found, which were both in external appearance and in genitalia patterns close to D. bupleurella , but showed a 6.36% p-distance in DNA-barcode, while barcodes show a 2% difference compared to D. saharae from Teruel, separating into two reciprocally monophyletic clusters. This suggested they were at least closely related, but left open the question of conspecificity. A male reared by Walsingham from Tenerife in 1907 was the key to this so far unanswered question: it has genitalia like D. saharae from Teruel, but in external appearance is like the females from Tenerife. The lack of genitalic separation suggests that the Teruel and Tenerife specimens are conspecific, in spite of their different external appearance. The different external appearance of the Canary Island population, in combination with the corresponding external features of both sexes of the Canary Island population justify the treatment as two separate subspecies.