Rheotanytarsus hoffeinsorum
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publication ID |
https://doi.org/ 10.26879/621 |
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publication LSID |
lsid:zoobank.org:pub:BAA44C0D-C497-4CED-85D7-B74A2A2AAEB4 |
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persistent identifier |
https://treatment.plazi.org/id/59790D07-F92E-3203-F6A4-011F14AFFCC7 |
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treatment provided by |
Felipe |
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scientific name |
Rheotanytarsus hoffeinsorum |
| status |
sp. nov. |
Rheotanytarsus hoffeinsorum View in CoL
Giłka, Zakrzewska and Krzemiński sp. nov.
Figures 2 View FIGURE 2 , 3 View FIGURE 3
zoobank.org/ 45416C6E-B107-40B0-87BA-052F53F0249E
Type material. Holotype. Adult male (tarsi of fore and mid legs missing, wings damaged in part) preserved in 9 x 9 x 3.5 mm piece of amber ( Eocene , ~40-45 Ma, Gulf of Gdańsk; CCHH 242-6 ; Figure
ZAKRZEWSKA, KRZEMIŃSKI, & GIŁKA: TANYTARSINI IN BALTIC AMBER
2.1); animal syninclusion: Ceratopogonidae (1 male).
Derivation of the name. The specific epithet honours Christel and Hans Werner Hoffeins in commemoration of their contribution to the study of fossil insects.
Diagnosis. Gonostylus stout, slightly narrowed in distal part. Anal tergite with distinct round field bearing strong median setae. Anal point long, narrowed in mid length, broadened in distal part, with swollen apex. Superior volsella reniform, with posteriorly directed rounded apex. Stem of median volsella bone-shaped, ca. 25 μm long, with 4 leaf-shaped separate lamellae.
Description. Adult male (n = 1).
Total length ca. 2.5 mm.
Head ( Figure 2.2 View FIGURE 2 ). Eyes bare, with well-developed dorsomedian extensions. Frontal tubercles absent. Antenna with 13 flagellomeres, AR ca. 0.95. Length of palpomeres 2-5 (μm): 32, 113, 145, 213. Clypeus with at least 13 setae.
Thorax chaetotaxy. Ac at least 9; Dc at least 7, Pa 4, Scts at least 14.
Wing. Observable parts of the wing typical for Tanytarsini and Rheotanytarsus , apices of wings and chaetotaxy unobservable ( Figure 2.2 View FIGURE 2 ).
Legs. Spur of fore leg tibia not observed. Mid and hind leg tibia with 2 separated combs, teeth length up to 20 μm (mid leg) and 30 μm (hind leg); each comb bearing spur, ca. 45 μm long (mid leg) and ca. 50 μm long (hind leg). For length of leg segments and leg ratio see Table 4.
Hypopygium ( Figure 3 View FIGURE 3 ). Gonostylus stout, ca. 120 μm long, longer than gonocoxite, broadest near base, slightly narrowed in distal part, apex widely rounded, with row of strong setae on median margin in distal half. Anal tergite semicircular, with distinct round field bearing strong median setae. Anal point typical of the genus, long, narrowed in mid length, broadened in distal part, with swollen apex, bearing long narrow crests and three posterolateral setae on each side ( Figure 3.1, 3.2 View FIGURE 3 ). Superior volsella reniform, slightly elongated, with posteriorly directed rounded apex ( Figure 3.3 View FIGURE 3 ). Digitus not observed. Stem of median volsella bone-shaped, ca. 25 μm long, with four leaf-shaped separated lamellae ( Figure 3.4-6 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 ). Inferior volsella reaching one third the length of gonostylus, with distinctly swollen head-like apex bearing stout setae (setae omitted on Figure 3.2 View FIGURE 3 ).
Remarks. Rheotanytarsus is a species-rich and greatly heteromorphic extant genus, but only two (the oldest) species are known from Eocene Baltic amber: Rh. alliciens Giłka and Zakrzewska, 2013 , and Rh. hoffeinsorum described here. These species differ distinctly from each other (cf. Giłka et al., 2013; see the key). Rh. hoffeinsorum combines some species-specific characters (the median volsella with bone-like stem bearing leaf-shaped separated lamellae) with those typical of extant species, and thus perceived as constant within the genus (the hypopygial anal tergite with the round field bearing median setae, the stout anal point with swollen apex, and the posteriorly directed superior volsella) ( Figure 3 View FIGURE 3 ). Essential information on the systematics, zoogeography and phylogeny of the genus have been published based on extant representatives distributed worldwide (Kyerematen et al., 2000; Kyerematen and Saether, 2000; Andersen and Kyerematen, 2001; Kyerematen and Andersen, 2001; Saether and Kyerematen, 2001).
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