Catamicrophyllum beroni, Vagalinski, 2024

Vagalinski, Boyan, 2024, Catamicrophyllum beroni sp. nov. - the first European record of the genus Catamicrophyllum Verhoeff, 1901 (Diplopoda: Julida: Julidae), Zootaxa 5397 (2), pp. 239-250 : 240-244

Catamicrophyllum beroni sp. nov.

Figs 1–3 , 5

Material examined. Holotype ( NMNHS): ♁ (unbroken, right antenna broken off), Bulgaria, Rila Mts , Seven Rila Lakes , Sedemte ezera (Seven Lakes) Hut, 2200–2290 m a.s.l., 18.IX.1997, P. Beron leg. Paratypes: 5 ♁♁ ( NMNHS) (four cut in 2 or more pieces, with dissected gonopods, one unbroken), 1 juv. (unbroken), 1 ♁ ( NHMD) (unbroken), same collecting data as for holotype .

Diagnosis. A species of the genus Catamicrophyllum , belonging to the caucasicum -group, as defined by Enghoff (1995), being most similar to C. caucasicum . Differs from the latter species by a smaller body size (males with L = ca 18 mm on average and H <1.9 mm, vs. L = ca 25 mm on average and H> 1.9 mm in C. caucasicum ), as well as by the somewhat more slender body proportions (sensu Enghoff 1995) ( Fig. 5 ); by the dorsal margin of the pre-anal ring (almost) completely adhered to paraprocts’ caudal contour, vs. same forming a minute epiproct in C. caucasicum ; and by the following details of the opisthomere: intermediate lamella (l) forming two well-developed crests, vs. same represented by only one, lateral crest in C. caucasicum ; hamulus (h) being somewhat clavate apically, vs. same being slender all along in C. caucasicum ; and terminal process (t) being piri-/ampulliform, vs. same being slender and tapering in C. caucasicum .

Etymology. Honours Dr. Petar Beron, one of the most renowned Bulgarian zoologists and speleologists who has found countless new invertebrate taxa throughout his career, including this surprising millipede species.

Description. Measurements: holotype in S X or XI, with BRF 39 + 1 + T, L = 21 mm, H = 1.7 mm; paratype ♁♁ in S X–XII, with BRF 35–41 + 0–2 + T, L = 15.5–21.5 mm, H = 1.6–1.85 mm.

Colouration (apparently somewhat faded from the ethanol) ( Fig. 1 ): Prozonae grey; metazonae medially dark brown to blackish, grey at suture and at posterior margins, the latter also with ochre tinges; sigilla conspicuous, with short light stripes between them and suture; head dark-brown with a broad, blackish band between eye patches and antennae; collum dark brown, submarginally blackish, margins ochre-brown; pre-anal ring grey, marginally dark-brown to blackish, paraprocts dark brown; legs mostly dark brown, proximal podomeres lighter.

Head ( Fig. 1B ): With 35–40 pigmented ommatidia arranged in a roughly semicircular/semielliptic field; rows difficult to count (ommatidia strongly reduced in number and jumbled in dorsal part of the eyefield). Vertigial, supralabral and labral setae: 2, 5–7 and 28–36, respectively. Antennae ca 1.1 times as long as head; lengths of antennomeres: 2> 3> 5 ≥ 4> 6; 5 1.3–1.4 times as long as broad and 1.3–1.4 times as broad as 2; 5 and 6 with a whorl of sensilla basiconica bacilliformia at distal margin, those on 5 somewhat longer, roughly as long as the four apical sensilla. Mandibular stipites forming a rather small, rounded anteroventral lobe; several striae at posteroventral corner. Labrum tridentate. Gnathochilarium ( Fig. 2A ): stipes with 3 long distal setae and a parabasal group of several short and stiff setae; stipital palps normally developed, apical sensilla missing (possibly brokenoff); promentum rather large, separating lamellae linguales almost halfway, the latter each bearing three proximal and two distal setae.

Trunk and legs: Collum smooth, except for a longitudinal groove alongside anterolateral margin, just frontal to lateral corner. Body rings very slightly vaulted. Prozonae mostly smooth, with very short and shallow, scattered, dash-like grooves. Metazonae normally striated, striae deeper and more densely set ventrally, n Schub = 5–7; metazona of ring 1 striated only ventrally, its ventral margin forming a small rounded lobe oriented mesad. Ozopores placed on pro-metazonal suture in more anterior rings and up to 1× their diameter behind it in more posterior rings; suture moderately to strongly arched at ozopore level. Walking legs relatively short: ML ca 0.6 times as long as H. Tarsus of ML ca 1.15–1.25 times as long as tibia and ca 2.9–3.3 times as long as main claw; all walking legs with very fine accessory claw being somewhat longer than main claw.

Telson ( Fig. 1C ): Pre-anal ring with several disto-dorsal setae (fallen out in part of the type specimens, including the holotype), without epiproct: dorsal margin not or barely protruding beyond hind contour of paraprocts. Hypoproct broadly rounded, tightly adhering under paraprocts; with a row of ca a dozen submarginal setae. Paraprocts with 2–3 dense rows of setae alongside posterior/mesal margins, without clear division of longer and shorter setae; rest of surface non-setose.

Male sexual characters: Leg-pair 1 ( Fig 3A ) with 3 complete segments, compact, mostly parallel hooks; tibial outgrowth rather short and rounded, with several transverse folds apically on ventral side; tarsal remnant (always?) present as a small rounded hump. Leg-pair 2 slightly thicker and longer than following legs; all legs with strongly pronounced adhesive pads on postfemur and tibia, except for last several pairs in which the postfemoral pads are absent or vestigial. Flanges of pleurotergum 7 ( Fig. 3B ) ventrally forming massive, prismatic lobes with a conspicuous groove in its ventral side, originating from both pro- and metazona, (almost) touching one-another behind gonopodal sinus. Penis ( Fig. 3C ) stout, mostly parallel-sided, apical part clavate, with indiscernible apical lobes, rather short and thick, roughly cylindrical terminal lamellae directed almost completely laterad, and a convex, undivided median lobe.

Gonopods: In situ distal part of the promere protruding ventrad in front of the lobes of pleurotergum 7, slightly exceeding level of the latter; tip of mesomere sometimes visible just mesally to the lobes. Promere (P in Figs 2B, C, E & 3D ) very slender, bent gently posteriad, with parallel sides and a rounded tip looking clavate in side view; posterior surface subapically rugose, with several setae just basally to the rugose part, a flat lobe (pl) at mid-height, and a short mesal ridge (mr) at base. Mesomere (M in Figs 2B, C, E & 3D ) shorter, narrower and more strongly bent posteriad than promere; apex narrowly rounded, anteriorly rugose, corresponding to the posterior rugosity of promere; subapically from mesal side a rounded lobe sometimes giving the impression of a short bifurcation. Opisthomere (O in Figs 2B, C, E & 3D ) shorter than both pro- and mesomere, mostly straight, gradually narrowing distad, apically bearing a long and slender hamulus ( Fig. 2D and h in Figs 2B, C, E & 3D ) directed posteriad, distally bent more or less ventrad, ending with a lanceolate widening with a denticulate dorsal surface, giving the hamulus a slightly clavate appearance; and a rather short piri-/ampulliform terminal process (t) directed ventroanteriad; intermediate lamella (l) forming two crests: a mesal (mc) and a lateral one (lc).

Distribution. Known only from the type locality: Bulgaria: Rila Mts: Seven Rila Lakes district: vicinity of Sedemte ezera (Seven Lakes) Hut ( Fig. 6 , red triangle).

Remarks. Apart from the strong morphological resemblance to C. caucasicum , C. beroni sp. nov. seems to be also ecologically similar to the former species. Both of them occur in mountainous habitats, including above the timberline, in rocky alpine and subalpine meadows (see also Enghoff 1995).

A one-day field trip to the type locality in 2023 did not yield further specimens of C. beroni sp. nov. It is very likely that the species also inhabits the higher parts of the forest belt, possibly in greater densities than in the alpine zone (see the discussion).

It is worth noting that C. beroni sp. nov. is the only fourth species of the entire tribe Paectophyllini recorded from Europe: Macheiroiulus compressicauda Verhoeff, 1901 and Symphyoiulus impartitus ( Karsch, 1888) are known from Greece (the latter also from Asian Turkey) ( Enghoff 1995 and 1990, respectively), while the mostly northwestern Anatolian Paectophyllum ferrugineum Enghoff, 1995 was recently found on the Greek island of Lesvos ( Zafeiriou & Agapakis 2021)

Figures

FIGURE 1. Catamicrophyllum beroni sp. nov., ♁ holotype (NMNHS). A. Whole body, lateral view. B. Head and anterior part of trunk. C. Posterior part of trunk with telson. Scale bars: 1 mm.

FIGURE 2. Catamicrophyllum beroni sp. nov., ♁ paratypes (NMNHS). A. Gnathochilarium, ventral view. B. Right gonopods, mesal view. C. Distal part of left gonopods, postero-mesal view. D. Distal part of hamulus, mesal view. E. Right gonopods, lateral view. Abbreviations: h: hamulus (distal part broken-off in C), l: intermediate lamella (partly broken in all pictures), lc: lateral crest, M: mesomere, mc: mesal crest, O: opisthomere, P: promere, pl: posterior lobe, t: terminal process. Scale bars: 0.3 mm (B, E), 0.2 mm (A, C), 0.02 mm (D).

FIGURE 3. Catamicrophyllum beroni sp. nov., ♁ paratype (NMNHS). A. Left leg 1, mesal view. B. Left flange of pleurotergum 7, meso-lateral view. C. Penis, posterior view. D. Left gonopods, lateral view. Abbreviations: h: hamulus, l: intermediate lamella, M: mesomere, O: opisthomere, P: promere, pl: posterior lobe, t: terminal process. Scale bars: 0.2 mm.

FIGURE 5. Slenderness of body of males of Catamicrophyllum caucasicum (Attems, 1901) (x: data of Enghoff (1995); +: present data) and Catamicrophyllum beroni sp. nov. (o) expressed as relation of vertical diameter to number of body rings.

FIGURE 6. Distribution of the genus Catamicrophyllum Verhoeff, 1901: pink area—summarised distribution based on literature records; red triangle—type locality of C. beroni sp. nov. Scale bar: 200 km.