Milandanielia intermedia ( Feider, 1950 )

Felska, Magdalena & Mąkol, Joanna, 2015, Morphological and molecular characteristics of Milandanielia intermedia (Feider, 1950) (Trombidiformes: Microtrombidiidae) with data on its biology and ecology, Zootaxa 4007 (1), pp. 29-44 : 30-42

Milandanielia intermedia ( Feider, 1950)

Microthrombidium geographicum var. intermedium Feider, 1950: 218 . Dimorphotrombium [sic!] geographicum var. intermedium: Feider 1952: 607 . Dimorphothrombium intermedium: Feider 1955: 106 .

Milandanielia intermedia: Gabryś 1999: 71 .

Type locality. 51°09’83.93”N, 17°09’42.28”E, tree and bushes stand with thick substrate, Wrocław, Poland.

Diagnosis. Adult. Distal ctenidium: 4–7 spines (plus paradont), proximal ctenidium: 3–7 spines, radula: 3–7 spines. One basidont at lateral face of palp tibia. Sensillary area of crista metopica with accessory posterior process. Double eyes sessile. Dorsal opisthosomal setae of two types. Longer setae arcuately bent, proximal (ca 1/3) part of stem with few long setules; distal (ca 2/3) part with dense cover (brush) of setules arising along outer surface of stem. Shorter setae straight or slightly bent, with relatively long and sparsely distributed setules covering entire stem. Three pairs of genital acetabula.

Deutonymph. One ctenidium with 3–6 spines (plus paradont). Radula with two spine-like setae. Two pairs of genital acetabula. Setation sparser than in adults. For other characters, see diagnosis of adults.

Larva. Gnathosoma with toothless stephanostome. Hypostomalae (tritorostral setae, bs) with ca eight fingerlike projections. fPp=0-N-N-NNN-NNNNNNζω. Minute, spine-like setae on PaFe and PaGe in dorsal position. Normal setae on PaTi and PaTa smooth. Scutum and scutellum longitudinally striated. Scutum quasi rectangular in outline, with three pairs of non-sensillary setae (AM, AL smooth or with minute barbs, PL with setulae) and a pair of indistinctly barbed (almost smooth) trichobothria. Stolascutum present. Scutellum quasi oval in outline, with a pair of c1 setae shifted to posterior half of sclerite. fD=(2)4-6-4-4-4 (including c1—on scutellum). Plates of c2 and of d1 enlarged; the latter separate, larger than c2 plates. fV=6, fCx=2-1-1, all setae with setulae. Solenidia on genua I– III long, extending beyond anterior margins of tibiae. Tarsi I–III terminated with double claws and claw-like empodium. Inner claw on tarsus III reduced to smilum; scopa and lophotrix (branched, not bifurcate distally) present. Normally developed claws on tarsi I–III with subterminal spurs.

Description. Adult ( Figs 1–9 ). Standard measurements (incl. data on neotype, female) in Table 1. Small to medium Microtrombidiidae . Colour in life reddish. Idiosoma oval in shape, densely covered with setae.

character data on neotype instar sample size mean min.–max. gnathosoma

ChCl 56 AD 20 49 41–57 DN 2 33 32–34 PaTr 49 AD 20 39 30–49 DN 2 27 27 PaFe 181 AD 20 160 146–181 DN 2 80 77–84 PaGe 67 AD 20 51 40–67 DN 2 29 29 PaTi 90 AD 20 77 64–90 DN 2 40 39–41 Bas 42 AD 20 36 31–44 DN 2 27 25–28 Odo 48 AD 20 44 39–50 DN 2 30 30 PaTa (L) 64 AD 20 57 51–65 DN 2 30 29–30 idiosoma

IL 1475 AD 20 1177 883–1475 DN 2 583 473–694 IW 865 AD 20 751 531–872 DN 2 398 340–455 IL /IW 1.7 AD 20 1.6 1.3–1.8 DN 2 1.5 1.4–1.5 CML 351 AD 19 287 259–351 DN 2 159 156–161 RCM 195 AD 19 164 143–195 DN 2 81 80–83 S 142 AD 19 130 119–155 DN 2 90 84–96 SB 26 AD 19 23 20–26 DN 2 19 19 pPr 107 AD 19 77 67–107 DN 2 38 37–40 SAL 50 AD 20 45 39–53 DN 2 40 40–41 SAW 51 AD 20 45 38–53 DN 2 38 36–40 OL 59 AD 16 51 47–60 DN 2 36 35–37 pDS I 46 AD 20 46 39–53 DN 2 37 30 –45 ......continued on the next page character data on neotype instar sample size mean min.–max. pDS II 26 AD 20 29 26–33 DN 2 20 19–21 pVS 32 AD 20 32 28–37 DN 2 18 18 GOP (L) 211 AD 12 166 153–211 DN 1 86 –

GOP (W) 125 AD 12 123 111–154 DN 1 56 –

AOP (L) 105 AD 12 115 101–136 DN 1 55 –

AOP (W) 77 AD 12 86 75–98 DN 1 42 –

legs

Cx I 115 AD 18 121 107–130 DN 2 76 74–79 Tr I 75 AD 18 69 53–85 DN 2 50 45–54 bFe I 147 AD 19 127 112–147 DN 2 62 60–64 tFe I 118 AD 20 109 95–129 DN 2 51 48–53 Ge I 140 AD 20 119 99–141 DN 2 67 66–69 Ti I 136 AD 20 123 94–141 DN 2 71 69–73 Ta I (L) 263 AD 20 236 211–264 DN 2 145 144–146 Ta I (W) 138 AD 20 121 108–138 DN 2 81 78–83 Leg I 994 AD 18 897 794–995 DN 2 522 519–525 Cx II 119 AD 18 117 97–130 DN 2 60 56–65 Tr II 84 AD 19 71 50–87 DN 2 36 33–39 bFe II 114 AD 20 91 75–114 DN 2 44 42–46 tFe II 79 AD 20 70 55–82 DN 2 43 42–45 Ge II 91 AD 20 77 57–91 DN 2 42 40–44 Ti II 105 AD 20 86 71–106

......continued on the next page Gnathosoma. Palps ( Fig. 1 ) robust. Medial surface of palp tibia ( Fig. 2 ) with two ctenidia and radula. Distal ctenidium with 4–7 spines (plus paradont), proximal ctenidium with 3–7 spines; radula composed of 3–7 spines. Lateral face of palp tibia ( Fig. 3 ) with one basidont, arising close to palp tarsus base and with normal, sparsely setulose setae. Palp tarsus with one solenidion located at ca half-length of segment and with ca five eupathidia in distal position. Normal setae on palp tarsus distinctly setulose.

Idiosoma, dorsum. Anterior process of crista metopica ( Fig. 4 ) elongated, slightly narrowing anteriorly. Sensillary area round, with a pair of smooth or very weakly barbed sensillae and with inconspicuous accessory posterior process. Posterior process of crista well developed, less than 1/2 length of anterior process. Double eyes sessile, placed on oval sclerites, located antero-laterally to sensillary area of crista. Dorsal opisthosomal setae ( Figs 5, 6 , 9 ) of two types. Longer setae (pDS I) arcuately bent, covered with setules arising along outer surface of stem; proximal (ca 1/3) part of stem with few long and sparsely distributed setules; distal (ca 2/3) part with dense cover (brush) of setules. Shorter setae (pDS II) straight or slightly bent, with long, sparsely distributed setules. Setal bases almost parallel-sided, much wider than stem, with longitudinally striated sides.

Idiosoma, venter. Ventral setae simple, setulated. Genital orifice surrounded with epivalves and centrovalves ( Fig. 7 ). Epivalval setae setulated, centrovalval ones smooth. Setae covering both valves similar in length. Three pairs of genital acetabula. Valves surrounding anus covered with moderately setulated setae, longer than genital setae.

Legs. Leg I and IV longer than legs II and III. Tarsus I oval in shape, inflated, always longer than tibia I ( Fig. 8 ). All leg segments densely covered with normal setulated setae. Specialized setae present on leg I (Ge–Ta), II ( Tr, Ge–Ta), III (tFe, Ge–Ta), IV ( Tr, tFe, Ge–Ta).

Deutonymph. Standard measurements in Table 1. Smaller and more sparsely setose than adult. Medial face of palp tibia with one ctenidium, composed of 3–6 spines (plus paradont) and radula formed of two spine-like setae. Lateral face of palp tibia with strong basidont arising close to palp tarsus base and with ca 6–7 normal, either setulated or weakly barbed setae; seta shifted to most anterior position almost smooth. Palp tarsus with one solenidion placed on lateral side, at ca half-length of segment and with ca five terminal eupathidia. Two pairs of genital acetabula.

Larva ( Figs 10–23 ). Standard measurements in Table 2 (all specimens reared from eggs, unfed). Leg chaetotaxy in Table 3. Color in life orange.

character sample size* mean min.–max. gnathosoma

bs 21 15 15–16 cs 18 11 9–13 PaFe 19 18 16–19 PaGe 20 15 14–16 PaTi 20 10 8–12 PaTa 20 6 5–7 Odo 20 6 5–8 idiosoma

IL 20 327 292–353 IB 18 184 160–202 IL /IB 18 1.79 1.65–2.00 LS 18 139 128–148 WS 17 144 132–150 AM 18 28 26–32 AA 20 55 51–61 AL 21 19 17–23 AW 19 100 93–105 PL 21 38 34–40 PW 19 131 121–137 S 17 83 74–92

......continued on the next page * larvae obtained from clutches deposited by seven females.

Tr I 1 B

Fe I 6 B

Ge I 4 B, 2 σ, 1κ Ti I 6 B, 2 φ, 1 κ Ta I 16–17 B, 1 ω, 1 ε, 2 ζ Cx II 1 B

Tr II 1 B

Fe II 5 B

Ge II 2 B, 1 σ, 1 κ Ti II 5 B, 2 φ

Ta II 12–14 B, 1 ω, 1 ε, 1 ζ Cx III 1 B

Tr III 1 B

Fe III 4 B

Ge III 2 B, 1 σ

Ti III 5 B

Ta III 9–11 B

Gnathosoma. Chelicera ( Fig. 10 ) composed of cheliceral base and movable claw, latter with two teeth along inner edge of blade. Stephanostome ( Fig. 11 ) shaped as open ring, with internal horseshoe-like, toothless sclerite inserted between two cuticular sheaths. Dorsally, stephanostome extended into two lamellar projections ( Figs 11 , 18, 19 ). Paired, smooth adoral setae (cs) located dorsally, close to stephanostome edge. Ventrally, a pair of thick hypostomalae (tritorostral setae, subcapitular setae, bs), each seta with ca eight finger-like, distal protuberances ( Fig. 11 ). Palpal formula, fPp=0-N-N-NNN-NNNNNNζω, comprises two short spine-like setae located dorsodistally on palp femur and palp genu, three smooth setae on palp tibia (one seta of comparable length to odontus, located dorsally, one very short seta located medially, at level of odontus base and one elongated seta in ventral position) and eight setae on palp tarsus ( Figs 11, 12 ). Odontus divided, except for the most basal part, with diverging terminations. Palp tarsus ( Fig. 12 ) with eight setae, including solenidion and eupathidium. Normal setae on palp tarsus smooth.

Idiosoma, dorsum ( Fig. 13 ). Anterior and posterior dorsal sclerite (scutum and scutellum) with longitudinal striation made of cuticular folds ( Fig. 20 ). On scutum, folds delicate in central surface, becoming thicker (robust) laterally. Antero-lateral parts of scutum bent to ventral side of body (stolascutum), with cuticular folds meeting at ca half-length, making an impression of cuticular pattern being present on scutal surface ( Fig. 18 ). Non-sensillary setae on scutum: AM and AL delicate and smooth or with few barbs, PL relatively thick, setulated. One pair of trichobothria (S), covered with minute barbs ( Fig. 13 A). Double eyes (each composed of two lenses) located laterally to scutum, at level between S and PL setae. Scutellum quasi oval in shape, with posterior margin more convex in comparison with anterior one. Cuticular folds on scutellum similar to those covering lateral parts of scutum. NDV=30 (incl. setae on scutellum). fD=(2)4-6-4-4-4, including c1-c3 (c1 on scutellum, arising behind midlevel of sclerite; plates of c2 enlarged), d1-d3 (plates of d1 enlarged, almost round, separate, larger than c2 plates), e1- e2, f1-f2, h1-h2 (setae h2 markedly longer than h1; h1 similar in length to setae assigned to rows C–F). fV=6. fCx=2-1- 1, medial coxala I (1a) slender, bifurcate terminally, lateral coxala I (1b), coxalae II (2b) and III (3b) as well as intercoxal setae III (3a) stouter, with short setules in distal part of stem. Both c1 and PL resemble, with respect to their shape and length, remaining opisthosomal setae of rows C–F. Setae c3, d2-d3, e1-e2, f1-f2, h1-h2 inserted in small platelets.

Idiosoma, venter ( Figs 14 , 18, 21 ). fCx=2-1-1. All coxalae (1a, 1b, 2b and 3b) with setules, especially distinct in distal half of stem. Setae 3a more slender than 3b, with minute setules, arising between coxae III at level of anterior margin of coxal plate (in unengorged specimens). Claparède’s organs placed laterally between coxae I and II. Intercoxal area with one pair of setae located between coxae III ( Fig. 14 ). Anal opening surrounded with membranous, unsclerotized valves. fV=2u-2-2 ( Fig. 21 ). Stems of ventral setae more delicate than those of dorsal setae.

Legs ( Figs 15–17 , 22, 23 ). Segmentation formula: 6-6-6. For chaetotaxy of coxae - see above (idiosoma, venter). Tarsus I ( Fig. 22 ) and II terminated with paired claws and claw-like empodium. Claws and empodia covered with few lateral splinters, claws also with indistinct subterminal spurs. Tarsus III with normally developed outer claw, empodium and modified inner claw (smilum). Scopa and lophotrix present ( Fig. 23 ). Outer (posterior) claw trifid at termination ( Fig. 23 ). Lophotrix composed of two branches diverging proximally, close to lophotrix base. One branch nude, other branch with ca 5–6 setules diminishing in length towards lophotrix termination.

Type material. Neotype: female no. H3042 is deposited in the Bavarian State Collection of Zoology, Munich, Germany.

Other material. Two larvae, obtained at laboratory conditions from female designated as neotype—in the Bavarian State Collection of Zoology, Munich, Germany. The remaining material—in the collection of the Department of Invertebrate Systematics and Ecology, Institute of Biology, Wrocław University of Environmental and Life Sciences.

Biology. Field data. The representatives of active postlarval forms of M. intermedia were observed in the field in the spring, summer and autumn, with a remarkable increase of adult abundance in May (Fig. 24). Single specimens extracted from samples collected in January as well as distribution of records between August and January (Fig. 24) confirm that adults but also deutonymphs which have not reached the adult instar before winter constitute the hibernating instars. As no larvae were collected in the field, the spectrum of hosts remains unknown. Laboratory data. Oviposition was observed in May and June. Field collected females deposited 6– 34 eggs (n=8); the majority of eggs were laid in clusters, whereas single eggs were distributed separately on the substratum (the actual fecundity rate cannot be ascertained since females may have started oviposition prior to being captured). The eggs, yellow in color, developed into prelarvae within 23 days (10–35, n=9), and into larvae within the next nine days (4–14, n=9). The total development time between oviposition and larval emergence was 32 days (19–39, n=9). The emergence of larvae was recorded in late June and in July (Fig. 24).

FIGURE 24. Phenology of Milandanielia intermedia . Data on adults (AD) and deutonymphs (DN) based on field observations; time of larval (LV) emergence recorded during laboratory experiment; n AD=49, n DN=3, n LV=12. For LV number of clutches counted.

Molecular ID. The amplification of barcode COI region, followed by sequencing, resulted in obtaining a reliable 619 bp and 643 bp long contigs beginning at the 5’ end. Pair-wise sequence alignment resulted in obtaining one sequence, 581 bp long. The genetic distance between sequences (K2P) was 0.7%.

Figures

FIGURE 9. Milandanielia intermedia, adult, SEM micrograph, dorsal opisthosomal setae of type I (pDS I) and II (pDS II).

FIGURES 1 – 8. Milandanielia intermedia, adult, (1) palp, medial aspect, radula and ctenidia omitted; (2) palp tibia and tarsus, medial aspect; (3) palp tibia and tarsus, lateral aspect; (4) crista metopica region; (5) dorsal opisthosomal seta of type I (pDS I); (6) dorsal opisthosomal seta of type II (pDS II); (7) genital sclerites; (8) genu, tibia and tarsus I, setae omitted.

FIGURES 10 – 14. Milandanielia intermedia, larva, (10) chelicera; (11) gnathosoma, ventral view; cr = internal cuticular sclerite, or = oral (= protorostral) seta, bs = tritorostral seta (hypostomala); (12) details of palp tibia and palp tarsus; (13) dorsal side of the body (without gnathosoma), A. sensillary seta of scutum; (14) ventral side of the body. Legs omitted beyond trochanters.

FIGURES 15 – 17. Milandanielia intermedia, larva, (15) leg I (trochanter – tarsus); (16) leg II (trochanter – tarsus); (17) leg III (trochanter – tarsus).

FIGURES 18 – 23. Milandanielia intermedia, larva, SEM micrographs, (18) gnathosoma, ventral view; (19) gnathosoma, antero-lateral view; (20) scutum and scutellum; (21) anal region; (22) tarsus I (basal part omitted); (23) tarsus III termination, inner view, in clockwise direction – lophotrix, scopa, smilum.