Quasicalathus uncinatus, Schmidt & Scholz, 2025
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publication ID |
https://doi.org/10.11646/zootaxa.5728.2.9 |
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publication LSID |
lsid:zoobank.org:pub:561AAFA2-BA32-4FAE-A15A-4CDE24624F9C |
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DOI |
https://doi.org/10.5281/zenodo.17895015 |
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persistent identifier |
https://treatment.plazi.org/id/A05B87FA-FFC2-985F-FF51-FF635C2FF83E |
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treatment provided by |
Plazi |
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scientific name |
Quasicalathus uncinatus |
| status |
sp. nov. |
Quasicalathus uncinatus sp. nov.
Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4
Holotype. Male in Baltic amber, with specimen label data SDEI-Amb-002552, deposited in Senckenberg Deutsches Entomologisches Institut , Müncheberg, Germany. The size of the amber piece measures approx. 21 × 10 × 8 mm (irregularly cut, Fig. 1a View FIGURE 1 ).
Preservation status: Using light microscopy, only the left side of the embedded carabid fossil can be investigated because an extensive flow line runs through the entire stone and covers half of the fossil ( Figs 1A–B View FIGURE 1 ). Using micro-CT, the specimen is rather well preserved. The exoskeleton is slightly shrunken and partly dissociated from the inclusion wall (negative). Based on the micro-CT scans, most external parts of the beetle body as well as the sclerotized parts of the genital armatures could be imaged using both, the fossilized exoskeleton (positive) and its negative imprint on the inclusion wall ( Figs 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 ). While the negative imprint most likely corresponds to the original external shape of the beetle, the positive is partially distorted due to shrinkage. However, several details of the exoskeleton are better preserved on the positive, e.g., the boundaries of the various plates of the exoskeleton and the insertion points of the setae (see Figs 4B, E, F, H View FIGURE 4 ). The right antenna of the fossil is missing, its left antenna, which is stretched dorsad, is invisible using light microscopy. However, because of its position, it was not included in the digitized amber.
Syninclusions: None.
Derivation of species epithet. The species epithet is derived from the Latin adjective uncinatus (= hooked) and refers to the shape of the tip of the aedeagal right paramere which is a diagnostic character of the new fossil species.
Diagnostic characters. Species with characteristics of Quasicalathus as defined by Schmidt et al. (2022). The combination of the following character states defines the new species:
Pronotum moderately constricted toward base, with lateral margin almost straight before base, and with basolateral angles obtuse ( Fig. 3C View FIGURE 3 ). Elytra with basal bead moderately concave ( Fig. 2A View FIGURE 2 ). Median lobe of aedeagus with ventral margin markedly convex in the middle ( Fig. 4D View FIGURE 4 ); styloid right paramere of aedeagus with distinct apical hook ( Fig. 4F View FIGURE 4 ).
Description. Measurements: Standardized body length: 7.5 mm.
Head length: 1.02 mm.
Head width including eyes: 1.39 mm.
Head width between eyes: 0.80 mm.
Eye length (left): 0.56 mm.
Eye length (right): 0.55 mm.
Pronotal length: 1.56 mm.
Pronotal width: 1.97 mm.
Pronotal apical width: 1.18 mm.
Pronotal basal width: 1.70 mm.
Pronotal basal angle: 120°.
Elytral humeral width: 1.84 mm.
Elytral length (left): 4.95 mm.
Elytral length (right): 4.95 mm.
Elytral width: 3.22 mm.
Metepisternum length (left): 1.07 mm.
Metepisternum width (left): 0.71 mm.
Metepisternum length (right): 1.08 mm.
Metepisternum width (right): 0.71 mm.
Metafemoral length (left): 2.02 mm.
Metafemoral length (right): 2.02 mm.
Aedeagus length: 1.26 mm.
Proportions: EyL/ HW(-) = 0.69–0.70.
PW/HW(+) = 1.42.
PW/PL = 1.26.
PW/PWb = 1.16.
PWb/PWa = 1.44.
EW/PW = 1.63.
EW/EhW = 1.75.
EL/EW = 1.53.
EpL/EpW = 1.51–1.52.
EL/FL = 2.45.
EL/AedL = 3.93.
Head: Shape and size of head, mandibles and eyes normal for Quasicalathus . Mentum tooth simple at tip, with two setae near its base; submentum with two setae each side in normal position ( Figs 3A, B View FIGURE 3 ). Microsculpture on head disc consists of very small slightly irregular meshes (magnification 80x).
Prothorax: Pronotal shape subquadrate, moderately constricted toward base, with lateral margin very slightly concave before base, almost straight, and with basolateral angles obtuse, the latter not protruded posteriorly; basal margin moderately convex, beaded laterally (level of basolateral angles); basolateral seta situated at margin ( Fig. 3C View FIGURE 3 ). Pronotal disc with transverse sculpticells of microsculpture, very narrow (magnification 80x). Prosternum impunctate, smooth, prosternal process laterally with a faint border near apex ( Figs 3D, E View FIGURE 3 ).
Pterothorax: Elytra slender, ovate, glabrous, humeral tooth absent; basal bead moderately concave with humerus protruded anteriorly, and with basal margin forming an angle of about 125° with lateral margin ( Fig. 2A View FIGURE 2 ); striae deeply engraved, with punctures very fine but evident, intervals moderately convex ( Figs 1B, C View FIGURE 1 , 2A View FIGURE 2 ). Parascutellar seta present ( Fig. 1B View FIGURE 1 ). Third interval with a single rather short and thin discal seta situated behind the elytral middle, distinctly before the end of the apical elytral 2/3, adjoining second stria ( Figs 1B, C View FIGURE 1 ), with surroundings of setigerous puncture not depressed; intervals 5 and 7 without discal setae. Umbilicate series consists of 14 (left side) resp. 15 (right side) setae, whereby a grouping into a humeral series with five setae is evident due to a significant gap to the sixth seta (the distance between the fifth and sixth seta corresponds to the distance between the first and fourth seta); the sixth seta is followed by an additional, much larger gap to the seventh seta (it corresponds to almost twice the distance between the fifth and sixth seta) ( Fig. 3F View FIGURE 3 ). Intervals with sculpticells of microsculpture transverse, very narrow, narrower than on pronotum (magnification 100x). Metepisternum elongate ( Fig. 3G View FIGURE 3 ). Hindwings fully developed.
Legs: Length and shape as in other Quasicalathus species; male protarsomeres dilated ( Fig. 4A View FIGURE 4 ); mesocoxa with a single ridge seta; metacoxa trisetose ( Fig. 3H View FIGURE 3 ); metatrochanter with seta present ( Fig. 3H View FIGURE 3 ); metafemur with two setae on ventral surface, and with dorsoapical setae present ( Figs 3I, J View FIGURE 3 ); metatibia in male not densely pubescent; tarsi without pubescence or wrinkles on dorsal surface; meso- and metatarsomeres I–IV without external and internal lateral grooves; fifth tarsomeres with a single pair of dorsal setae, and with two pairs of ventral setae; claws pectinate ( Fig. 4B View FIGURE 4 ).
Abdomen: Ventrites 3–6 smooth, each with two setae in normal position (male; Fig. 2C View FIGURE 2 ).
Aedeagus: Size of median lobe averaged for Quasicalathus , in lateral view markedly bent from base to apex, with ventral margin sinusoidal due to a marked convexity in middle of median lobe, and with terminal lamella markedly bent downward ( Fig. 4F View FIGURE 4 ); in dorsal view broad in basal 9/10 and abruptly narrowed toward terminal lamella, with the latter slender tongue-shaped ( Fig. 4C View FIGURE 4 ). Right paramere styloid with distal portion very long and slender, terminated in a distinct apical hook ( Fig. 4F View FIGURE 4 ); left paramere ovoid ( Fig. 4E View FIGURE 4 ).
Recognition. The new species differs from all previously described Quasicalathus species by the styloid right paramere of aedeagus which forms a distinct apical hook ( Fig. 4F View FIGURE 4 ) (apex simple in other Quasicalathus species; Schmidt et al. 2022), and by the markedly convex ventral margin of the aedeagal medial lobe ( Fig. 4D View FIGURE 4 ) (straight or slightly convex in other Quasicalathus species; Schmidt et al. 2022). The pronotum of Q. uncinatus sp. nov. is more markedly constricted toward base than in Q. elpis (PW/PWb = 1.16 instead of 1.03–1.13 mm in Q. elpis ), and the basolateral angles are more obtuse (120° instead of 95–115° in Q. elpis ; Schmidt et al. 2022), the elytral basal bead is less concave ( Fig. 2A View FIGURE 2 ). Due to its pronotal and elytral shape, the new species is more similar to Q. agonicollis Schmidt & Will, 2022 , however, it is larger ( 7.5 mm instead of 6.7–6.9 mm in Q. agonicollis ; Schmidt et al. 2022).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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