Nebria ( Falcinebria ) dracocephala, Sasakawa, 2025

Nebria ( Falcinebria) dracocephala sp. nov.

Figs 2 View Figures 2–5 , 10–12 View Figures 10–12

Nebria reflexa View in CoL : Uéno (1985): 56 (part; subgenus not specified).

Type material.

Holotype: ♂ ( KS), Japan • Shizuoka Prefecture, Hamamatsu-shi, Mount Ryûtô-san , alt. 1200 m, 3-X-2006 [no collector data] . Paratypes: 1 ♀ ( KS), same data as the holotype ; 1 ♂ ( KS), Japan • Shizuoka Prefecture, Shizuoka-shi, Aoi-ku, Mount Sasa-yama , alt. 1500 m, 29-X-2005, Masato Mori leg. ; 2 ♂ 1 ♀ ( KS), Japan • Shizuoka Prefecture, Tenryu-shi, Sakumacho, Mount Idoguchi-yama, the upper reaches of Aizuki-gawa River , 18-V-1996, Hiroshi Nishida leg.

Diagnosis.

Similar to the locally adjacent species N. dichotoma , but distinguished by the shape of the endophallus, particularly the left lateroapical lobe composed of two sub-lobes and the dorsoapical lobe with apex not bifurcated (bifurcated in N. dichotoma ).

Description.

Body length: ♂, 9.95–10.73 mm, 10.26 ± 0.34 mm ( n = 4); ♀, 10.89–11.13 mm, 11.01 ± 0.17 mm ( n = 2). Sternum 7 with two setae on each ventrolateral side in both male and female. Other external structures, coloration, and chaetotaxy as in other related species that had been previously regarded as N. reflexa ( Sasakawa 2020) . Dorsobasal lobe absent. Dorsomedian lobe undeveloped, with a minute, slender protrusion or a weak, wide swelling. Dorsoapical lobe with a simple-shaped (i. e., not bifurcated) protrusion at the basal part, the size of which varies among localities, ranging from smaller than that of the dorsobasal lobe to almost the same size as the laterobasal lobes; the dorsomedian area with a large protrusion, the apex of which is simply rounded or bifid, varying among localities; the apical portion bent ventrally, with the dorsal bend discontinuous in lateral view, more or less swollen. Laterobasal lobes large; the left lobe more rectangular in shape than the right in ventral view; at the distal end of both right and left lobes, the endophallus-base side corner more protruding than the opposite side; ventrobasal surface largely swollen on both right and left lobes, distinctly visible in lateral view. Ventrobasal swelling absent. Right lateroapical lobe markedly wide in dorsal view, with the endophallus-base and - apex side corners protruding, resulting in a T-shape in dorsal view; the endophallus-base side corner more slender and protruding than the opposite side. Left lateroapical lobe composed of two sub-lobes, one on the left dorsolateral side and the other on the left lateral side of the endophallus; the sub-lobe on the dorsolateral side T-shaped, with the endophallus-apex side corner more robust and protruding than the opposite side; the sub-lobe on the lateral side large, with a simply rounded or slightly bifid apex, varying among localities. Gonopore protrusion bent at the base, directed toward the endophallus base; the observable part simply curved cylindrical, with no additional structures such as protrusions. Relative sizes of some lobes and protrusions are as follows: dorsomedian lobe <endophallus-apex side corner of left dorsolateral sub-lobe of left lateroapical lobe ≈ endophallus-base side corner of right lateroapical lobe <swelling of ventrobasal surface of laterobasal lobes <left lateral sub-lobe of left lateroapical lobe ≤ laterobasal lobe (including swelling of ventrobasal surface) ≤ protrusion on dorsomedian area of dorsoapical lobe.

Notes.

There was marked variation in endophallus morphology, both qualitatively (shape) and quantitatively (size). However, all specimens shared basic structures, such as the left preapical lobe composed of two sub-lobes and the dorsoapical lobe with protrusions on the dorsobasal, dorsomedian, and dorsoapical sides, none of which are possessed by other closely related species ( Sasakawa 2020, 2023 b; Sasakawa and Itô 2021). Given their morphological complexity, these shared characters are probably synapomorphies uniting the three populations rather than symplesiomorphies. Therefore, the three populations were treated as a single species. Morita and Hirai (2010) recorded “ N. reflexa ” from the Abe-tôge Pass, 9 km northwest of Mount Sasa-yama, and this specimen is also most likely N. dracocephala .

Etymology.

The specific name is a combination of the Latin draco (dragon) and the Latin cephalus, - a, - um (head), derived from the type locality Ryûtô-san, which means “ dragon’s head mountain ” in Japanese.