Lycoriella piristylata Vilkamaa, Hippa & Heller, 2013

Vilkamaa, Pekka & Menzel, Frank, 2019, Re-classification of Lycoriella Frey sensu lato (Diptera, Sciaridae), with description of Trichocoelina gen. n. and twenty new species, Zootaxa 4665 (1), pp. 1-67 : 12-14

Lycoriella piristylata Vilkamaa, Hippa & Heller, 2013

Literature. Lycoriella (Hemineurina) piristylata Vilkamaa, Hippa & Heller—Vilkamaa et al. (2013) : 52, fig. 3 A–C.

Discussion. Lycoriella piristylata was described in the former subgenus Hemineurina Frey based on the holotype and nine paratypes from Northern Finland, Norway and Sweden ( Vilkamaa et al. 2013). The species was provisionally placed in L. vitticollis group of Lycoriella (Hemineurina) but because it has a sensory pit on the first palpal segment, Lycoriella piristylata belongs—in spite of the completely reduced whiplash seta on the medial side of the gonostylus—to the genus Lycoriella Frey s. str. sensu Menzel & Mohrig (2000: 380) . Furthermore, the species has a bow-like bordered fore tibial organ, lacks spinose setae on the fore tibia, the tarsal claws are without teeth, the basal portion of antennal flagellomeres have long and appressed sensilla, the gonocoxae are long, ventrobasally separated in a v-shape, and the tegmen is membraneous and broadly roundish. Basoventrally in the intergonocoxal area—contrary to the original description by Vilkamaa et al. (2013: p. 53, fig. 3 A)—there is no medial lobe. At that place on the medial margin there are at most a few setae, as, for example, in L. lundstromi ( Frey, 1948) and L. vanderwieli ( Schmitz, 1920) .

Phylogeny and classification

The molecular phylogeny by Shin et al. (2013) challenged the monophyly of Lycoriella s. str. + ( Hemineurina + Coelostylina ) (only the L. inflata group was included in the ingroup of their analysis) suggested by Menzel & Mohrig (2000) on the morphological evidence. Shin et al. (2013) suggested that Hemineurina and Lycoriella s. str. are not closely related, as they appeared in different main clades in the phylogenetic tree. The morphological characters uniting Lycoriella s. str. and Hemineurina are indeed few: the presence of the whiplash seta and the pale and weak body setosity. Coelostylina Tuomikoski, 1960 (preocc.) is a junior homonym of Coelostylina Kittl, 1894 ( Gastropoda: Coelostylinidae ), and is here renamed as Stenacanthella nom. et stat. n. On the basis of the corrected nomenclature, the species groups of ‘ Coelostylina Tuomikoski’ sensu Menzel & Mohrig (2000: 380 , 384) are kept and re-named here as the St. freyi group and St. secundaria group.

Hemineurina , Trichocoelina and Stenacanthella have several putative synapomorphies: the intergonocoxal area is long and the apicoventral margin of gonocoxa is therefore short, the intergonocoxal area is almost exclusively with setose lobe(s), the gonostylar megasetae usually have basal bodies, the megasetae are mostly slender and at least some of them are oblique in position, the gonostylus is impressed, the apex of gonostylus is densely setose, the tegmen is at least partly sclerotized, and the fore tibia has spine-like setae among the ordinary vestiture (lacking in Lycoriella s. str.). Furthermore, Hemineurina and Trichocoelina as sister groups share as synapomorphies the similar intergonocoxal area with two lobes (in some species a medial lobe), the whiplash seta medial or subbasal in position, and a well-developed apical tooth of gonostylus. Following our present morphological interpretation, we agree with Menzel & Mohrig (2000) with the phylogenetic relationships of these three taxa, but propose raising them to genus rank: Stenacanthella nom. et stat. n. + ( Hemineurina stat. n. + Trichocoelina gen. n.). The genus Hemineurina here includes only the former L. inflata group with the type species Sciara conspicua Winnertz, 1867 , and the new genus Trichocoelina is established for the former L. vitticollis group (type species Sciara vitticollis Holmgren, 1883 ).

The maximum likelihood tree for the COI gene indicates that Trichocoelina gen. n. is monophyletic (Appendix 3). However, the genus Hemineurina Frey in the present sense represented by two morphotypes sensu Menzel & Mohrig (2000) — H. inflata and H. conspicua —appears at different positions in the ML tree. This result is of course preliminary and not representative because only one gene was included in our genetic analysis and the taxon sampling was very limited. But this taxonomic problem was not the focus of this study and will be discussed in a later revision of the Hemineurina species.

Diagnostic characters of the Lycoriella group of taxa

The traditional Lycoriella group of taxa (subgenera Lycoriella s. str., Lycoriella (Hemineurina) with Hemineurina stat. n. [former L. inflata group] and Trichocoelina gen. n. [former L. vitticollis group], Stenacanthella nom. et stat. n. [former Lycoriella (Coelostylina) ] and Bradysiopsis , can be distinguished from other genera of Sciaridae by the following characters: Body vestiture weak and pale (dark and strong in Bradysiopsis and some Stenacanthella ), fore tibia with a distinct tibial organ (densely setose and with arcuate boundary), gonostylus with two or more upcurved whiplash setae sub-basomedially (lacking in Bradysiopsis and Stenacanthella ), apical tooth and subapical/mesial megasetae present, intergonocoxal area of hypopygium or basoventral parts of gonocoxa mostly with lobe(s) or seta group(s). Species of Mohrigia Menzel, 1995 also have one or more whiplash setae on the gonostylus and an intergonocoxal lobe, but differ in having a modified apical tooth with megasetae inside, the tegmen narrow and with a dorsomedial sclerotized rim, the tarsal claws with tiny teeth, and a very short and weak aedeagal apodeme ( Menzel & Martens 1995; Menzel & Mohrig 2000). Camptochaeta Hippa & Vilkamaa, 1994 also has elongated seta(e) on their gonostylus, but these are strong and not whiplash-like (similar as in Mohrigia ). Camptochaeta can also be distinguished by typical lambda-shaped basal sclerotization in the gonostylus, stronger gonostylar megasetae, and by generally stronger and darker body setosity. Eugnoriste Coquillett, 1896 and Pseudolycoriella Menzel & Mohrig, 1998 also have a whiplash-like seta on the gonostylus, but the seta is downcurved and sub-apicoventral in position (not medial or subbasal as in Lycoriella s. str., Hemineurina and Trichocoelina ). Furthermore, Eugnoriste and Pseudolycoriella have teeth on the tarsal claws, and strong body setosity.

Key to genera of the former Lycoriella sensu lato group

Note. Some species of Trichocoelina lack the apical tooth or whiplash seta(e) on the gonostylus and in some species of Hemineurina the intergonocoxal lobe of hypopygium is distinguishable only as a few setae or is completely lacking.

1 Eye bridge not complete, interrupted in the middle and without ommatidia, apical gonostylar megaseta present, subapical and mesial megasetae absent, gonostylus basally with an up-curved whiplash seta on very high lobe-like basal body.............................................. Merizomma Sasakawa stat. n. (former subgenus Chorizomma Sasakawa ; preocc.)

- Eye bridge complete, united in the middle and with ommatidia, apical gonostylar megaseta absent, subapical and/or mesial megaseta(e) present, gonostylus without whiplash seta or subapical/mesial/subbasal whiplash seta(e) on short basal body(es) ................................................................................................... 2

2 Gonostylus with at least one whiplash-like seta, apex of gonostylus densely setose................................. 3

- Gonostylus without whiplash setae, apex of gonostylus sparsely setose.......................................... 5

3 Gonostylus with downcurved subapical whiplash seta, tarsal claws with teeth.......... Pseudolycoriella Menzel & Mohrig

- Gonostylus with upcurved medial or subbasal whiplash seta, tarsal claws without teeth............................. 4

4 Scutellum with 2 long and strong setae, R 1 short, merging with c well before base of M-fork, gonostylus mostly elongated and apically narrowed (when gonostylus somewhat thickened, then apical tooth very long)................................................................. Hemineurina Frey stat. n. (former L. inflata group of subgenus Hemineurina Frey )

- Scutellum with 4 (rarely 3) long and strong setae, R 1 long, merging with c shortly before base of M-fork, gonostylus thickened, apically usually roundish or lobe-like enlarged (when gonostylus very thick, then apical tooth short or lacking).............................................. Trichocoelina gen. n. (former L. vitticollis group of subgenus Hemineurina Frey )

5 First palpal segment long and narrow, scutellum with 4 strong setae, intergonocoxal area without lobe, gonocoxae separated, gonostylus convex, not impressed, with strong apical tooth (longer than the megasetae), all gonostylar megasetae without basal bodies, subapical in position......................................................... Bradysiopsis Tuomikoski

- First palpal segment enlarged, scutellum with 2 strong setae, intergonocoxal area with 3 lobes, or 1 medial lobe and two lobes or seta groups at bases of gonocoxae, gonocoxae united, gonostylus impressed, apical tooth very short or lacking (if present, then shorter than the megasetae), gonostylar megasetae with basal bodies, part of gonostylar megasetae medial or subbasal in position......................... Stenacanthella nom. et stat. n. (former subgenus Coelostylina Tuomikoski ; preocc.)

Genus Trichocoelina gen. n.

Type species: Sciara vitticollis Holmgren, 1883

Description. Male. Head. Eye bridge 2–4 facets wide. Coloration of antenna brown or scapus, pedicellus and/or 1 st flagellomere yellow, flagellomeres with unicolorous necks, necks short. Maxillary palpus with 3 segments, 1 st segment with dorsal patch of sensilla and a few sharp setae (without sensory pit). Face with many setae. Thorax. Brown and sparsely setose, setae usually pale. Scutellum with 4 (rarely 3) strong setae and many short setae. Katepisternum high and triangular, postpronotum non-setose. Legs. Yellow. Fore femur slender. Fore tibia with some spinose setae among vestiture and some spinose setae at apex. Fore tibial organ large and distinct, usually clearly demarcated, setae strong or fine, tibial spurs long, mid and hind legs with 2 equally long ones. Tarsal claws untoothed.

Wing. Fumose. Anal lobe small. Veins distinct. Fork of M very long and weakly arcuate; R and R 1 long, R 1 merging with c nearly at level of base of M-fork; apical part of R 5 with only dorsal macrotrichia. Abdomen. Pale brown and sparsely setose, setae usually pale and fine. Hypopygium. Apicoventral corner with only one long seta, intergonocoxal area of hypopygium long, with one medial, usually at least apically divided lobe, or two separate lobes at bases of gonocoxae. Gonocoxa normal to wide, as long as or longer than gonostylus. Gonostylus rather narrow to very voluminous, apically densely setose, medially impressed, with an apical tooth (missing only in one known species), with 5 to numerous, usually slender and slightly procurved megasetae, with one or a few subbasal whiplash setae. Tegmen as long as broad, or shorter or longer, weakly sclerotized, rounded or with different modifications apically, with very small and fine aedeagal teeth (or these apparently lacking), and with distinct aedeagal apodeme.

Female. Without diagnostic characters at species level.

Discussion. Trichocoelina gen. n. differs from Hemineurina in having the gonostylus usually broader and more strongly impressed or excavated, the ventrolateral margin extending over the basal parts of the megasetae, in having the megasetae more numerous and slender, usually with distinct basal bodies, the whiplash setae subbasal in position, and the tegmen usually only weakly sclerotized. The intergonocoxal area of hypopygium is longer and the apical part of gonocoxa shorter than in Hemineurina . Trichocoelina differs from Stenacanthella in having a whiplash seta on the gonostylus, in having stronger apical tooth, and no tendency to have three lobes in the intergonocoxal area. Trichocoelina differs from both Hemineurina and Stenacanthella in having 4 or 3, not just two, long and strong setae on the scutellum.

Distribution. Northern Holarctic, south of 50° N only in mountains over 1000 meters high.

Etymology. The name is formed from the latinized Greek words trichos, hair, and koilos, hollow, referring to the narrow megasetae in the medially hollowed gonostylus of most species.