Melogona sintica, Vagalinski, 2025

Vagalinski, Boyan, 2025, Melogona sintica sp. nov. - a surprising seventh member of Melogona Cook, 1895, with a key to species of the genus (Diplopoda: Chordeumatida: Chordeumatidae), Zootaxa 5728 (3), pp. 549-560 : 550-555

publication ID	https://doi.org/10.11646/zootaxa.5728.3.5
publication LSID	lsid:zoobank.org:pub:10C388BB-BD73-4414-A83F-8C5383DF4394
persistent identifier	https://treatment.plazi.org/id/5F0887FF-DC36-8259-FF5B-FA5A0F65615C
treatment provided by	Plazi
scientific name	Melogona sintica
status	sp. nov.

Treatment

Melogona sintica sp. nov.

Figs 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 6A, D View FIGURE 6

Material examined. ♂ holotype ( NMNHS) (in 2 pieces, anterior gonopods dissected), Bulgaria, Blagoevgrad District, ca 1.5 km W of v. Kulata, 41.383°N, 23.3461°E, 70 m a.s.l., on and next to a soil levee between agricultural land and the left bank of Struma River, grassy, densely overgrown with Clematis , Rubus s. str., Prunus spinosa , sparse Salix , Populus , Ulmus , and young Quercus , pitfall trap, 16.I–03.III.2023, M. Naumova, G. Hristov, T. Trifonov, S.- T. Trendafilova leg.; 1 ♂ paratype ( NMNHS) (in 2 pieces; antenna, right pregonopodal legs cut-off; head, anterior gonopods, and half posterior gonopods used for SEM), same collecting data as for holotype; 1 ♂ paratype ( NMNHS) (in 3 pieces, anterior and posterior paragonopods, and anterior and posterior gonopods dissected; left antenna, leg-pair 2 & mid-body leg cut-off), same collecting locality and method as for holotype but 03.III–03.IV.2023, M. Naumova, G. Hristov, B. Vagalinski leg.; 1 ♂ paratype ( IBER) (in 3 pieces, anterior and posterior gonopods, and posterior paragonopods dissected), same collecting data as previous; 3 ♀ paratypes ( NMNHS) (unbroken, one with dissected right legs 1 & 2), same collecting data as previous; 1 ♀ paratype ( NMNHS) (unbroken), same collecting data as previous; 1 ♀ paratype ( IBER) (unbroken), same collecting data as for holotype.

Diagnosis. A species of Melogona with 28 body segments, like M. albanica , M. broelemanni , M. scutellaris and M. transsylvanica . Differs from M. scutellaris most noticeably by the higher number of ommatidia (on each side 14–16 in M. sintica sp. nov., vs. 7–12 in M. scutellaris ) and the shape of the syncolpocoxite of the anterior gonopods (with a narrow apex in M. sintica sp. nov. vs. a broadly rounded apical margin in M. scutellaris ). The new species is very similar to M. albanica , M. broelemanni and M. transsylvanica in both external and gonopodal characters. Differs from these species mainly by details of the anterior gonopods, viz., syncolpocoxite roughly leaf shaped in anterior view (i.e. oblong, with convex side margins, gradually tapering in a narrow apical part), vs. same being broader distally, forming distinct, pointed, disto-lateral corners and a massive apicomedian process in M. broelemanni or a small apicomedian hump in M. albanica , angiocoxites with an axe-like apex, vs. same being apically scoop/visor-like in M. broelemanni and M. albanica , and lateral lobes of syncolpocoxite nearly as high as wide, vs. same being markedly oblong in vertical direction in M. broelemanni ; syncolpocoxite rather slender, 2.5–3 times as high as wide, with a narrow apical part forming a short, blunt tip turned anteriad, vs. same being stouter, 1.5–2 times as high as wide and with a broadly rounded to flattened apex in M. transsylvanica , angiocoxites apically axe-like vs. same being scoop/visor-like in M. transsylvanica , and lateral lobes of syncolpocoxite nearly as broad as the syncolpocoxite itself, vs. same being narrower in M. transsylvanica .

Etymology. Honours the Sintians – an ancient Thracian tribe that lived around the middle current of Struma River in present-day northern Greece and southwestern Bulgaria. Also referring to the currently excavated ancient city of Heraclea Sintica by the village of Rupite, Bulgaria, ca 10 km in a straight line from the type locality. Adjective.

Description. Measurements.With 28 segments including telson, penultimate segment not bearing legs; holotype male ( Fig. 2A View FIGURE 2 ) 6.7 mm long, VD 0.63 mm; paratype males 7.3–8.7 mm long, VD 0.63–0.77 mm; paratype females 8.9–10.2 mm long, VD 0.86–1.02 mm,

Colouration (after up to one and a half month stay in formaldehyde-propylene glycol solution) ( Fig. 2 View FIGURE 2 ). Yellowish-beige; head and antennae in both sexes and legs in males with darker, brownish tinges.

Head. Relatively evenly setose, setae of various lengths. Labrum ( Fig. 4A View FIGURE 4 ) with 3 median teeth and 4+4 labral setae. Gnathochilarium ( Fig. 4A View FIGURE 4 ) with promentum broad, triangular, without setae; lingual plates with 5+5 setae arranged in a longitudinal row or with the basal-most seta positioned laterally, perpendicular to the row; stipital palps relatively long, mesal ones almost twice as broad as lateral ones, both bearing several apical sensilla. Antennae ca 2.1 times as long as head; relative lengths of antennomeres (excluding 8th): 3>5>4>2>6≥7>1. 14–16 blackish ommatidia on each side arranged in 6 rows: 1+1+2+3+4+(3–5).

Trunk. Collum narrower than head, anterior margin strongly convex, posterior margin very gently concave, lateral edges narrowly rounded, hidden under the mandibles. Segments mostly smooth, metazonae with sparse, short and very fine longitudinal striae. Paraterga completely absent. Macrochaetae rather short (ca 11% of rings’ VD) and thin, somewhat longer in first and last several segments. CIX = 1.3; MIX = 0.5; MA = 150˚.

Telson. Epiproct with a pair of paramedian and 2+2 marginal setae. Paraprocts with 3+3 submarginal setae. Hypoproct with a pair of distal setae.

Walking legs ( Fig. 3A–F View FIGURE 3 ). Leg-pairs 1 ( Fig. 3A View FIGURE 3 ) and 2 ( Fig. 3B View FIGURE 3 ) shorter than following legs, with tarsal combs in both sexes; male genital openings placed on small humps meso-ventrally on coxae 2. Next leg-pairs in males ( Fig. 3C–E View FIGURE 3 ) slightly incrassate, with a dense row of flattened and pointed papillae ventrally on tarsus, these progressively diminishing in size and number towards posterior end of body. Tarsus of mid-body leg ( Fig. 3F View FIGURE 3 ) ca 3.4 times as long as tibia.

Anterior paragonopods (leg-pair 7) ( Fig. 3G View FIGURE 3 ). Reduced to very small knob-like coxites bearing several setae; telopodital remnants not evident.

Anterior gonopods (leg-pair 8) ( Figs 4B–D View FIGURE 4 , 6A, D, G View FIGURE 6 ). Syncolpocoxite ( Fig. 6A, D View FIGURE 6 , sc in Fig. 4B View FIGURE 4 ) relatively elongate, appearing leaf shaped in anterior view, laterally at mid-height with expanded margins bent anteriad, distally gradually narrowing, ending with a short, blunt tip turned anteriad, basally bearing two rounded, lamellar, densely pilose lateral lobes ( ll). Angiocoxites ( Figs 4C, D View FIGURE 4 , 6G View FIGURE 6 , ac in Fig. 4B View FIGURE 4 ) slender, with a deep mesal groove, apically forming an axe blade-like structure turned mesad.

Posterior gonopods (leg-pair 9) ( Fig. 4E View FIGURE 4 ). With the usual for the genus conformation. Anterior coxal process ( ap) massive, spatulate, gradually tapering to a club-like distal part directed somewhat posteriad. Median coxal process ( mp) distally bifurcate into a larger blade-like branch ( bb) and a smaller spinigerous branch ( sb). Posterior coxal process or pseudoflagellum ( pf) very long and slender, with a brush-like ending, i.e. a slightly enlarged fimbriate structure. Telopodites ( t) massive, rounded, densely setose lobes.

Posterior paragonopods (leg-pair 11) ( Fig. 4F View FIGURE 4 ). Coxites ( c) stout, bent anteriad, somewhat tapering distally, ending with a rounded tip, with a small posterior process ( pp) at mid-height. Telopodites ( t) much smaller than coxites. Distal parts of both coxites and telopodites setose.

Type locality. Bulgaria, Blagoevgrad District, ca. 1.5 km W of village Kulata , a riverside agricultural land, at a soil levee overgrown with various grasses, shrubs and deciduous trees ( Fig. 1 View FIGURE 1 ) .