Gnomognathus interfectus ( Carl, 1941 )

Sudhakaran, Nikhila & Kuruvila, Manju Elizabeth, 2025, A new millipede species of the genus Gnomognathus Attems, 1942 (Diplopoda, Spirostreptida, Harpagophoridae) from South India, Zootaxa 5659 (3), pp. 335-356 : 342-344

Gnomognathus interfectus ( Carl, 1941)

Figs 5 , 6 , 9D

Material examined. 1 male, Paniyeli Poru (10°10.011’N, 76°36.360’E), Ernakulam , Kerala, 11 December 2024 ; 1 female, Thommankuthu (09°57.381’N, 76°50.065’E), Idukki , Kerala, 6 December 2024 ; 1 female, Mulamkuzhy (10°11.090’N, 76°31.965’E), Ernakulam , Kerala, 18 December 2024 ; hand-collected by Nikhila Sudhakaran (RDZ-ACP-SS207).

Diagnosis. The gonopods of G. interfectus ( Figs 5 , 6 , 9D ) are most similar to those of G. macracanthus Form B ( Fig. 9C ) in that the anterior coxal fold (AC) of both species is with a hook-like mesal process (mp) and backwardbent antero-lateral process (alp); telopodite without femoral spine, with strong tibial spines (ts) on a projection and apical part branched and lobed with additional spines but G. interfectus differs from Form B by the broad, platelike AC; AC with a slightly twisted and backward-curved hook-like mp, a narrow and elongated alp, and without any additional processes on the lateral margin; telopodite with three short tibial spines (ts) on a hemispherical projection; palette (pa) broad and with small additional spines (as) (in G. macracanthus Form B mesal process is strong, lamellate, and hook-like, and the antero-lateral process appears short; telopodite with two tibial spines on an elbow-shaped projection, palette narrow and tapering, and additional spines longer and placed on a bulge on the apical part close to the palette). Species with a diameter ≤ 2 mm.

Descriptive notes (male). Overall color in alcohol dark grey with golden yellow, dorsally with a dull orange diffused line. Length ca. 29 mm, width ca. 1.5 mm, body rings 54 podous + telson. Five supralabral foveolae. Mandibular stipites without hook-like ends. Legs without longitudinal depressions on prefemur and femur. Weak pads on postfemur and tibia restricted to legs towards the anterior end. Preanal process curved downward and pointed.

Gonocoxite very similar to the illustrations of Carl (1941). AC with three processes: mp hook-like, curved backward with a slight twist, paramedian process (pp) with longitudinal triangular ridge (tr) on the posterior surface, and alp narrow, elongated, and bent backward. PC with triangular postero-lateral process (plp) and baso-lateral process (blpPC) ( Figs 5A, B , 6 , 9D ).

Telopodite shows some variations from the illustrations of Carl (1941). Free part of the telopodite short, transparent, and expanded distally; three ts, one long and two short, placed inside a groove on the margin of a hemispherical projection.Apical part of telopodite split into two branches: pa with a reduced number of xyrochaetae (11) and as (2), palette continuous with the hemispherical projection; the second branch consists of two lamellate lobes (ll), almost equally sized, joined along their length, and parallel to each other. The ll adjacent to pa with a dense covering of fine setae and translucent, spine-like marginal projections (also with setae) ( Figs 5C, D , 6 ).

Descriptive notes (female). Length ca. 30–34 mm, width ca. 1.5–2 mm, body rings 51–52 podous rings + telson.

Notes. A transparent region is present on the anterior coxal fold.

Remarks. The main difference from the original illustration is the presence of lamellate lobes and the setae and spine-like projections on one of them. But this may be a detail that Carl (1941) could have overlooked, as the transparent nature of the lobes makes them difficult to distinguish ( Fig. 6 ).

Figures

FIGURE 5. Gnomognathus interfectus, gonopod (RDZ-ACP-SS207). A. Right gonopod without telopodite, anterior view. B. Right gonopod without telopodite, posterior view. C. Right telopodite, lateral view. D. Right telopodite, mesal view (adjusted). Abbreviations. AC: anterior coxal fold; alp: antero-lateral process; as: additional spines; blpPC: baso-lateral process of posterior coxal fold; ll: lamellate lobes; mp: mesal process; pa: palette; pp: paramedian process; plp: postero-lateral process; px: paracoxite; tr: triangular ridge; ts: tibial spines. (Telopodite shaft broken). Scale bars = 1 mm.

FIGURE 6. A. Illustration of Gnomognathus interfectus from Carl (1941), lateral view. B. Gnomognathus interfectus (RDZ- ACP-SS207), left gonopod with telopodite, lateral view. Images not to scale.

FIGURE 9. Gonopods of previously described Gnomognathus species. A. G. nanus (Carl, 1941). B. G. minusculus (Attems, 1936). C. G. macracanthus (Carl, 1941) (Form B). D. G. interfectus (Carl, 1941). E. G. macracanthus (Carl, 1941) (Form A) (Figures reproduced from Attems (1942) and Carl (1941)).