Short Communication |
Corresponding author: Valeria Lencioni ( valeria.lencioni@muse.it ) Corresponding author: Joel Moubayed ( jm.aquabiol@free.fr ) Academic editor: Fabio Laurindo da Silva
© 2021 Valeria Lencioni, Joel Moubayed.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lencioni V, Moubayed J (2021) Synorthocladius federicoi sp. nov., a new species occurring in the middle basin of the Adige River, northern Italy (Diptera, Chironomidae, Orthocladiinae). ZooKeys 1057: 105-116. https://doi.org/10.3897/zookeys.1057.68175
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An adult male Synorthocladius was collected in the middle basin of the Adige River in the city of Verona, northern Italy. A combination of atypical characters for the genus signalled a new species. Synorthocladius federicoi sp. nov. is here diagnosed and described. The new species is known only from its type locality and is presumed to be a local biogeographical representative of the Italian Pre-Alps. An emended generic diagnosis, a key to known Synorthocladius from Europe and comments on the taxonomic position of the new species are given.
Adige River, Alps, chironomids, orthoclads, adult male, morphology
According to data on the taxonomy and geographical distribution of known Synorthocladius species from the Palaearctic and neighbouring biogeographical regions (
The emended generic diagnosis of the genus given in
The studied adult male was collected using a light trap along the banks of the Adige River (altitude = 61 m a.s.l.; 45°26'58.68"N, 10°58'52.81"E), preserved in 80% ethanol and cleared of musculature in 90% lactic acid for about 70 minutes. When clearing was complete, the material was washed in two changes of 50–60% ethanol to ensure that all traces of lactic acid were removed. It was then mounted in polyvinyl lactophenol. Before the final slide mount (dorsal), the hypopygium including tergite IX, the anal point, the gonocoxite and the gonostylus were viewed ventrally and laterally and all morphological details were drawn from all sides. The rest of the abdomen was preserved in 85% ethanol for possible future DNA analysis. Terminology and measurements follow those of
The generic diagnosis of Synorthocladius in Thienemann (1935), emended in
Holotype : adult male, leg. L. Latella; Adige River in the city of Verona, Veneto Region, Italy (altitude = 61 m a.s.l.; 45°26'58.68"N, 10°58'52.81"E); 13 April 2020.
The holotype (on one slide and abdomen in one tube) is deposited in the entomological collection of MUSE-Museo delle Scienze, Trento, Italy (Accession number: cINV0017_s61v73).
The new species is named ‘federicoi’ after Federico, the first author’s son, who has an inherited passion for insects and contributed to the collection of chironomids with the light trap.
Head : Frontal tubercles broadly semi-circular, coronal triangle and coronal suture reduced, coronal setae absent; temporals 6; last flagellomere of antenna bilobed apically, with numerous curved sensilla chaetica; AR 0.90. Palpomere 3 without sensilla coeloconica. Clypeus inverted safety helmet shaped, with 5 setae. Thorax: Lobes of antepronotum not gaping, thinner basally; acrostichals 2; dorsocentrals 7–8, uniserial; prealars 4; humeral pit absent; scutellars 6; squama with 4–5 setae. Legs. Sensilla chaetica on tibiae and tarsomeres ta1–ta5 of PI–PII, only on tarsomeres ta1–ta5 of PIII. Abdomen: Tergites II–VI with a unique distribution of setae in two longitudinal rows. Tergite IX broadly semicircular, bearing a hump, postero-median and caudal areas with 15 setae mostly located close to base of anal point. Anal point triangular, short and sharply pointed, distinctly curving upwards distally. Sternapodeme orally projecting; phallapodeme unusual comma-like. Virga present, branched apically. Gonocoxite with dorsal distal half parallel-sided; ventral side broadly expanded, bearing several stout setae placed in 2 arched rows. Superior volsella swollen. Inferior volsella subtriangular, inwardly projecting into a spherical lobe, which is hyaline and bare. Gonostylus atypically shaped; globular when viewed dorsally, bean-like in ventral view; crista dorsalis absent; megaseta well developed, tongs-like, visible only in dorsal view.
Adult male (n = 1; Figs
Colouration. Blackish species with greenish to brownish legs. Head dark brown including eyes and pedicel; antenna brownish. Thorax with contrasting blackish to dark green mesonotal stripes, area between thoracic stripes greenish; scutellum distinctly contrasting, blackish to brownish. Wing pale brown. Anal segment brown to dark brown with contrasting dark brown to pale gonostylus.
Head. (Fig.
Male imago of Synorthocladius spp. Head (dorsal, left side) with vertex, coronal area and temporals of A S. federicoi sp. nov. B S. semivirens. Antenna, apex of last flagellomere of C, D S. federicoi sp. nov. E S. semivirens. Palpomere 3 of F S. federicoi sp. nov. G S. semivirens. Clypeus of H S. federicoi sp. nov. I S. semivirens. Lobes of antepronotum and acrostichals of J S. federicoi sp. nov. K S. semivirens. Humeral area of L S. federicoi sp. nov. M S. semivirens. The arrows indicate some distinguishing characters.
Thorax. Lobes of antepronotum (Fig.
Wing. Brachiolum with 1 seta. Number and distribution of setae on veins: R, 5; R1+2, 0; R2+3, 1; remaining veins bare; squama with 4–5 setae in 1 row.
Legs. Femora of PI and PII subequal, tarsomere ta5 of PI–PIII of same size (100 µm long). Tibial spurs present on PI–PIII; length (in µm) of spurs: 50 (PI), 60 (PII), 25 (PIII); pseudospurs absent. Sensilla chaetica present on tibiae and tarsomeres ta1–ta5 of PI–PII, only present on tarsomeres ta1–ta5 of PIII. Length (µm) and proportions of legs as in Table
Synorthocladius federicoi sp. nov. Length (µm) and proportions of prothoracic (PI), mesothoracic (PII) and metathoracic (PIII) legs.
fe | ti | ta1 | ta2 | ta3 | ta4 | ta5 | LR | BV | SV | BR | |
---|---|---|---|---|---|---|---|---|---|---|---|
PI | 625 | 710 | 425 | 355 | 245 | 150 | 100 | 0.60 | 2.07 | 3.14 | 2.40 |
PII | 645 | 615 | 295 | 175 | 140 | 110 | 100 | 0.48 | 2.96 | 4.27 | 3.10 |
PIII | 675 | 745 | 380 | 235 | 190 | 115 | 100 | 0.51 | 2.81 | 3.74 | 2.30 |
Abdomen. Tergites II–VI (Fig.
Male imago of Synorthocladius spp. Chaetotaxy of tergites II–VI of A S. federicoi sp. nov. B S. semivirens. S. federicoi sp. nov. C hypopygium in dorsal view D tergite IX and anal point in lateral view E megaseta, dorsal F gonostylus, other aspect in ventral view G hypopygium, ventral H inferior volsella I virga. S. semivirens J tergite IX and anal point in lateral view K anal point, dorsal L, M inferior volsella, two aspects. The arrows indicate some distinguishing characters.
Female, pupa and larva: unknown.
According to
The new species is a Synorthocladius based on characters provided in the generic descriptions of
1 | Inferior volsella with spherical apex (Fig. |
S. federicoi sp. nov. |
– | Inferior volsella finger-like or nose-like (Fig. |
S. semivirens |
The newly described species can be considered as a local biogeographic representative of the Venetian Pre-Alps. Consequently, the description here of S. federicoi sp. nov. increases the total number of valid species of Synorthocladius from Europe to two.
Larvae of Synorthocladius species are typically rheobiontic, occurring especially in rheocrene mountain springs and streams fed by groundwater (krenal) (
Synorthocladius federicoi sp. nov. is known only from its type locality in the Venetian Pre-Alps (a mountain range of the Italian Alps). It would appear to be a biogeographic representative of lotic habitats delimited by the south-eastern part of the Italian Alps. It is likely to be more widespread in similar lotic habitats or Alpine streams of northern Italy.
Chironomid species encountered with S. federicoi sp. nov. include: Conchapelopia pallidula (Meigen, 1818), C. melanops (Meigen, 1818), Paramerina cingulata (Walker, 1856), Cardiocladius fuscus Kieffer, 1924, Cricotopus annulator Goetghebuer, 1927, C. levantinus occidentalis Moubayed-Breil & Ashe, 2011, C. tremulus (Linnaeus, 1758), Eukiefferiella devonica (Edwards, 1929), E. ilkleyensis (Edwards, 1929), E. lobifera Goetghebuer, 1934, Paracricotopus niger (Kieffer, 1913), Parametriocnemus stylatus (Spärck, 1923), Rheocricotopus chalybeatus (Edwards, 1929), Synorthocladius semivirens (Kieffer, 1909), Tvetenia calvescens (Edwards, 1929), Micropsectra atrofasciata (Kieffer, 1911) and Rheotanytarsus curtistylus (Goetghebuer, 1921).
The authors are grateful to Leonardo Latella (Natural History Museum of Verona, Italy) for collecting the holotype, to Patrick Ashe for his helpful reading before submission, and to the two reviewers Peter Langton and Eugenyi Makarchenko for their constructive corrections that greatly improved the manuscript.