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Two new species of Caeculisoma (Trombidiformes: Erythraeidae) from Madagascar

Saboori, Alireza ¹ ; Starý, Josef ² ; Masoumi, Hamidreza ³ and Cakmak, Ibrahim ⁴

¹✉ Jalal Afshar Zoological Museum, Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj, Iran & Department of Plant Protection, Faculty of Agriculture, Aydin Adnan Menderes University, Aydin, Türkiye.
²Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, České Budějovice, Czech Republic.
³Acarological Society of Iran, Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj, Iran.
⁴Department of Plant Protection, Faculty of Agriculture, Aydin Adnan Menderes University, Aydin, Türkiye & Department of Research and Innovation, Saveetha School of Engineering, SIMATS, Thandalam, Chennai-602105, Tamil Nadu, India.

2023 - Volume: 63 Issue: 4 pages: 1225-1259

https://doi.org/10.24349/vqaq-42d1
ZooBank LSID: E6345D9F-F9A5-4633-8DFF-1D1207AF6AC8

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Original research

Keywords

soil mites taxonomy morphology systematics identification key Madagascar fauna Ethiopian region

Abstract

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Introduction

Berlese (1888) defined the genus Caeculisoma based on adult specimens of the type species, C. tuberculatum collected from Argentina and Paraguay. Later, the following species are described based on larval (L) or post-larval (P) stages or both (L, P): C. afrum Cooreman, 1958 (P) from Congo, C. argus Vitzthum, 1926 (P) from Indonesia (Sumatra), C. carmenae Haitlinger, 2008 (L) from South Africa, C. claviger Canestrini, 1897 (P) from Papua New Guinea, C. cooremani Southcott, 1972 (L) from Australia, C. cordipes Vitzthum, 1935 (P) from French Polynesia, C. darwiniense Southcott, 1961 (L, P) from Australia, C. haussa Beron, 2000 (P) from Nigeria, C. hunanica Zheng, 2002 (L) from China, C. huxleyi Southcott, 1972 (L) from New Zealand, C. infernale Vitzthum, 1926 (P) from Indonesia (Sumatra), C. io Southcott, 1961 (P) from Australia, C. johnstoni Womersley, 1934 (P) from Australia, C. montanum (Rainbow, 1906) (P) from Australia, C. mouldsi Southcott, 1988 (L) from Australia, C. nasutum Hirst, 1928 (P) from Australia, C. nestori Haitlinger, 2004 (L) from Brazil, C. sparnoni Southcott, 1972 (L) from Australia, and C. sulcatum (Vitzthum, 1924) (P) from Indonesia (Krakatau, Sunda Strait) and Papua New Guinea, (Canestrini 1897, 1898; Rainbow 1906; Vitzthum 1924, 1926, 1935; Womersley 1934; Cooreman 1958; Southcott 1961, 1972, 1988; Beron 2000; Zheng 2002; Haitlinger 2004, 2008).

Among these 20 species, only C. darwiniense was from larval and post-larval instars. All species have been reported from the southern hemisphere except C. haussa and C. hunanica. Australia is more investigated for Caeculisoma. Only three species have been described from Africa (Democratic Republic of Congo, Nigeria and South Africa).

In this paper, we describe two new species of post-larval Caeculisoma from Ambohitantely Special Reserve and Andasibe National Park, Madagascar.

Material and methods

The mite specimens were extracted using a Winkler apparatus, preserved in 70% ethanol, cleared in Nesbitt's fluid, and mounted in Hoyer's medium on microscope slides (Walter and Krantz 2009). Figures were drawn, and measurements were calculated using an AxioImager A2 (Carl Zeiss, Germany) compound microscope with phase contrast and DIC illumination. Photomicrographs were taken with an AxioCam 506 color (Carl Zeiss, Germany) digital camera. Measurements are given in micrometers (µm) and for holotype followed by paratypes in parentheses (for adults; for deutonymph paratypes range is given without parentheses). Terminology and abbreviations follow Gabryś (1992) and Mąkol (2005). The system defining the place of insertion of specialized setae (relative to segment length) used by Newell (1957) is used here.

Caeculisoma banari n. sp.

ZOOBANK: A92A23DD-4C28-41C9-8ACB-86A065BA8E97

Description

Adult female (n = 3)

Idiosoma (Figure 1a & Figure 3a) - Length: 2425 (2198–2293), width, 1837 (1606–1818). Colour was not recorded. Dorsal idiosoma is densely covered with two different types of setae. One is short and fan-like (flattened) with a strong mid-rib and minute projections along the mid-rib (Figure 1b & Figure 3b), 40–62 (40–52); the second type is long, filiform and densely barbed 129–235 (124–272) (Figure 1c, d & Figure 3c). The densely setose dorsum makes it difficult to clearly see the ventral idiosoma.

The crista metopica (Figure 3a) very long 1149 (1319–1327) and extends well beyond the middle of the idiosoma. The anterior sensillary area (ASA) prominent, oval with one pair of smooth ASens 247 (203–206) long, ~26 (30–32) fan-like setae, 51–71 (53–77) long, and 18 (15–18) long and filiform barbed setae, 252–308 (150–262) long, similar to those on dorsal idiosoma (Figure 2b). Anterior process (aP) absent. The posterior sensillary (PSA) area is approximately in the middle of the idiosoma; the distance between the anterior and posterior trichobothria insertions (ISD) is 790 (710–761). The posterior sensillary area (PSA) narrow, smooth (Figure 2c). The crista extends 214 (362–422), behind the posterior sensillary area (pP). PSens 245 (227–256) similar to ASens and smooth. The eyes are at 230 (177-181) (OCM) laterad from the center of the crista, OAS 531 (465–472), OPS 259 (238–296).

Ventral idiosoma is covered with two types of setae. One is short and fan-like (flattened) 51–71 (53–77) with a strong mid-rib and minute projections, similar in shape and size to the dorsal setae; second type is feather-like, 27–37 long (Figure 1e & Figure 3f). Median part of ventral idiosoma from the beginning of idiosoma to anus covered with feather-like setae; other parts covered with a mixture of fan-like and feather-like setae; behind anus only fan-like setae present. Genital opening (Figure 2j) 323 long (only visible in holotype) with two pairs of acetabula and epivalves and centrovalves, covered densely with thin barbed setae (Figure 2k). Anal valves (Figure 2l) oval, 101 (92) long, covered with many thin barbed setae (Figure 2m).

Gnathosoma dorsally covered with anterior crista metopica and fan-like setae and can′t be seen clearly. Subcapitulum (Figure 2e) covered with many barbed setae. Chelicerae very long, narrow, dagger-shaped, retractable into idiosoma, and reach behind coxae IV, emarginate except basal and distal ends (Figure 2d). Palps (Figure 2f) narrow, and linear. Trochanter and proximal end of femur could not be observed due to dense dorsal setae. For this reason, the palptrochanter and palpfemur were not measured. All palpal segments covered only with short and barbed setae as shown in Figure 3h for palpal tarsus. Odontus (Figure 3g) small, palp tarsus with 14 (13–15) omega (ω) (Figures 3g & i).

All legs (Figures 4–11) with six articulating segments (femur divided). Leg I the longest and leg II the shortest; Ta I longer and differs with other tarsi in shape (Figures 5c & d). Ta IV similar to that of legs II and III but slightly longer. Tubercles: Each Ti I-IV with one sub-distal tubercle placed 0.73d (0.74–0.75d), 0.62d (0.65–0.69d), 0.69d (0.71–0.72d), 0.74d (0.76d) respectively, and two distal tubercles (Figure 12c) in constrictions (there is a constriction at the distal end of each tibia which has no seta and there are only tubercles in it); all other segments with one distal tubercle except coxae, basifemora and tarsi.

Legs with different types of setae (Figures 4–11). Coxae: Coxal fields I-IV covered with fan-like setae, and some distal feather-like setae and a L-shaped ventro-distal peg-like seta (Figure 3d). Trochanters (a & b in Figures 4, 6, 8 & 10): Tr I-III with three types of setae (fan-like (Figures 1f & 2e), long barbed and round-ended, and longer, filiform barbed setae similar to the dorsal idiosoma setae) whereas Tr IV has the same types of setae and 1–2 long nude (dorsal one spine-like and ventral one thin) setae (Figures 4a & b). Basifemora (c & d in Figures 4, 6, 8 & 10): All basifemora covered with fan-like setae and long nude setae (except one thin ventral seta). Number of nude setae on BFe I-IV: 3–4, 3–5, 3–5, 3–6. Telofemora (c & d in Figures 4, 6, 8 & 10): All telofemora covered with fan-like setae, long nude setae and solenidia (theta, θ). Number of nude setae on TFe I-IV: 4–6, 3–4, 4–5, 6–7; one long barbed seta on TFe IV only in the holotype. Number of Theta on TFe I-IV: 6–11, 3–6, 7–9, 10–17. Genua (e & f in Figures 4, 6, 8 & 10): All genua covered with fan-like setae, long nude setae, feather-like setae with distinct stems and different sizes, and solenidia (sigma, σ). Number of nude setae on Ge I-IV: 11–13, 2–9, 5–8, 8–11. Number of sigma on Ge I-IV: 18–32, 8–10, 8–13, 17–23. Microsetae (κ) present on Ge I-II (Table 1, Figure 12a). Tibiae (a & b in Figures 5, 7, 9 & 11): Dorsal surface of tibiae covered with only fan-like setae; lateral surfaces covered with a mixture of fan-like, feather-like and nude setae; ventral surface covered with feather-like, nude, and barbed setae; solenidia (phi, φ) and sometimes microsetae present (Table 2, Figure 11b). Number of nude setae on Ti I-IV: 7–16, 1–7, 4–6, 3–7. Number of phi on Ti I-IV: 33–48, 8–10, 4–10, 3–5. There is one sub-distal tubercle and two distal tubercles at a constriction. There are no setae between these tubercles. Tarsi (c & d in Figures 5, 7, 9 & 11): Ta I about two times longer than other tarsi. Ta I covered with barbed setae, solenidia (omega, ω), eupathidia (zeta, ζ) and a famulus (epsilon, ε). The ω on Ta I were too numerous to accurately count. Number of ω on Ta II-IV: 11–18, 6–13, 5–11, ζ on Ta I-II: 2–4, 0–2, and a ε only on Ta I. There are no fan-like or nude setae on tarsi.

Measurements are in Table 1.

Deutonymph (n = 3)

Idiosoma - Length: 1068–1469, width, 875–1147. Color was not recorded when alive. Dorsal idiosoma is covered with two types of setae. One is fan-like (flattened) and short seta with strong mid-rib and minute projections, 32–57. The second setal type is long, filiform and densely barbed, 149–272. Idiosoma is densely covered with fan-like setae that obscured details of the ventral idiosoma.

The crista metopica very long 775–900 and extends well beyond the middle of the idiosoma. The anterior sensillary area is prominent, semi-oval with one pair of smooth ASens 167–217 long, 13–19 fan-like setae, 47–63 long, and 5–10 long and filiform barbed setae, 149–211 long, similar to those on dorsal idiosoma. Anterior process (aP) absent. The posterior sensillary area is approximately in the middle of the idiosoma; the distance between the anterior and posterior trichobothria insertions (ISD) 446–537. This posterior area is narrow and smooth. The crista still extends 177–243, behind the posterior area (pP). PSens 198 similar to ASens and smooth. Each eye is 99–146 (OCM) lateral from the center of the crista and approximately two thirds down the crista (OAS 281–346, OPS 161–191).

Ventral idiosoma with two different types of setae. One is short and fan-like (flattened) with strong mid-rib and minute projections; the second type is feather-like 27–37 long. Median part of ventral idiosoma from the beginning of idiosoma to anus covered with feather-like setae; other parts covered with a mixture of fan-like and feather-like setae; only fan-like setae present behind anus. Genital opening small, 58 long, without seta (only visible in a re-mounted paratype specimen ARS-20230808-1f; Figure 13a). Anal valves oval, 46–83 long, covered with 16–20 thin barbed setae.

Gnathosoma covered by the anterior crista metopica and fan-like setae making it difficult to clearly see the gnathosoma. Chelicerae are very long, narrow, dagger-shaped, retractable into idiosoma, and reach behind coxae IV, emarginate except basal and distal ends. Palps narrow, and linear. The base of femur cannot be seen clearly due to dense dorsal fan-like setae. For this reason, palp was measured from genu except for one specimen which was re-mounted it ventral side up. All palpal segments covered with short, barbed setae. Odontus small, palp tarsus with 7–8ω. Subcapitulum covered with many barbed setae.

All legs with six articulated segments (femur divided). Leg I the longest and leg II the shortest; Ta I longer and differs from other tarsi in shape. Ta IV similar to that of legs II and III but slightly longer. Tubercles: Each Ti I-IV with one sub-distal tubercle (0.69–0.72d, 0.65–0.66d, 0.62–0.72d, 0.74–0.77) respectively, and two distal tubercles in constrictions; all other segments with one distal tubercle except basifemora and tarsi.

Legs with different types of setae. Coxae: Cx I-IV covered with fan-like setae and some distal feather-like setae. There is one stout ventro-distal L-shaped peg-like seta on each Cx I-III. Trochanters: Tr I-III three types of setae (fan-like, long barbed and round-ended, and longer barbed filiform setae similar to those of dorsal idiosoma) whereas Tr IV has the same types of setae and may have an additional long nude seta. Basifemora: All basifemora covered with fan-like setae and long nude (all spine-like except one thin ventral one) setae. Number of nude setae on BFe I-IV: 2–3, 2–3, 1, 3–4 (3 nude + 1 long barbed seta on one side in paratype ARS-20230808-1d). Telofemora: All telofemora covered with fan-like setae, long nude setae and theta (θ). Number of nude setae on TFe I-IV: 3–5, 3–5, 3–4, 3–5 (4 nude + 1 long barbed seta on one side in paratype ARS-20230808-1f). Number of θ on TFe I-IV: 3–5, 0–3, 4–6, 7–11. Genua: All genua covered with fan-like setae, long nude setae, different sizes of feather-like setae with distinct stems and sigma (σ). Number of nude setae on Ge I-IV: 5–8, 2–4, 3–4, 5–8. Number of σ on Ge I-IV: 6–13, 3–5, 3–6, 12–15. Microsetae (κ) present on Ge I-II (Table 2, Figure 13e). Tibiae: Dorsal surface of tibiae with only fan-like setae; lateral surfaces covered with a mixture of fan-like, feather-like and nude setae; ventral surface covered with feather-like, nude and barbed setae. Phi (φ) and sometimes microsetae (κ) present on Ti I (Table 2, Figure 13f). Number of nude setae on Ti I-IV: 3–6, 0–2, 0–2, 4–5. Number of φ on Ti I-IV: 20–31, 4–7, 2–6, 2–3. There is one sub-distal tubercle, and two distal tubercles in a constriction. There are no setae between these tubercles. Tarsus: Ta I longer than other tarsi. Ta I covered with barbed setae, omega (ω), eupathidia (ζ) and a famulus (ε). The ω on Ta I were too numerous to count. Number of solenidia on Ta II-IV: 6–10, 2–7, 2–5, ζ on Ta I-II (Figures 13b & c): 1–4, 0–2, and a ε only on Ta I (Figure 13d). There are no fan-like or nude setae on the tarsi.

Measurements are given in Table 1.

Remarks

The new species differs from C. tuberculatum in in having fan-like and long filiform barbed dorsal idiosomal setae (vs. setae on tubercles and not as above), CML (1149–1327 vs. ~1900), ISD (710–790 vs. 1100); from C. montanum in having fan-like and long filiform barbed (vs. curved, spiniform with narrow sheath), length of body (LB) (2198–2425 vs. 3000); from C. argus (Figures 14a & b) in the CML (1149–1327 vs. ~1470), dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. cylindrical, uniformly thick with serrations), leg I (2749–2785 vs. 2200), leg II (1913–1955 vs. 1560), leg III (2057–2152 vs. 1740); from C. cordipes in the LB (2198–2425 vs. 1710), O-O (320–436 vs. 280), dorsal idiosomal setae (two different types vs. one type), AL setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. cylindrical, uniformly thick with serrations); Ta I (L) (499–540 vs. 890^*), Ta IV (L) (259–277 vs. 510^*); from C. sulcatum in WB (1606–1837 vs. 1100), dorsal idiosomal setae fan-like and long filiform barbed (vs. sparsely feathered setae and interspersed with long, simple, slender spine); from C. infernale in LB (2198–2425 vs. 1185), WB (1606–1837 vs. 720), dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. long, and strong spines, leg I (2748–2786 vs. 1515), leg II (1913–1955 vs. 1185), leg III (2057–2152 vs. 1315), leg IV (2802–2858 vs. 1515); from C. nasutum (Figures 14c & d) in the LB (2198–2425 vs. 1700), WB (1606–1837 vs. 1050), Ti I (534-603 vs. 350), Ta I (L) (499–540 vs. 310), dorsal idiosomal setae (two different types vs. one type), shape of fan-like setae (with small projections strong mid-rib vs. with minute projections in line on whole surface); from C. johnstoni (Figures 14e & f) in the dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. stout rod-like with strong short serrations); LB (2198–2425 vs. 1380), WB (1606–1837 vs. 812), CML (1149–1327 vs. 800), ISD (710–790 vs. 415), Ti I (534–603 vs. 400), Ta I (L) (499–540 vs. 290), leg I (2749–2785 vs. 2110), leg II (1913–1955 vs. 1300), leg III (2057–2152 vs. 1460), and leg IV (2802–2858 vs. 1950); from C. darwiniense (deutonymph) in the ASens (167–217 vs. 118), PSens (198 vs. 150), SBa (19–20 vs. 12), SBp (32–39 vs. 24), dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. tapering, curved, slender and fully barbed); from C. io in the dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. cylindrical, uniformly thick with serrations); from C. afrum in the dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. cylindrical, uniformly thick with serrations), CML (1149–1327 vs. 2000), ASens (203–247 vs. 170), ISD (710–790 vs. 1100), OCM (160–230 vs. 320) and from C. haussa in the dorsal idiosomal setae (two different types vs. one type), dorsal idiosomal setae fan-like and long filiform barbed (vs. cylindrical, uniformly thick with serrations), LB (1069–1462 vs. 1790), CML (775–900 vs. 700), ISD (446–437 vs. 405), Ta I (L) (277–305 vs. 240), and Ti IV (347–410 vs. 280). We were not able to compare our species with C. claviger (Figures 14g & h) due to an incomplete description, but Cooreman (1958) reported it had long club-shaped dorsal idiosomal setae. Based on Cooreman's report and pictures obtained from South Australian Museum (SAM), the new species differs from C. claviger.

^* Vitzthum (1935) wrote 0.089 µm and 0.051 µm for Ta I and IV, respectively. We suggest the measurements were in millimeters not micrometers.

Etymology

The species name banari is dedicated to our colleague, Dr. Petr Baňař (Brno, Czech Republic) renowned entomologist, specialist on soil Heteroptera, collector of numerous soil samples in Madagascar.

Type material

The female holotype (ARS-20230808-1a), two female paratypes (ARS-20230808-1b, 1c) and one deutonymph paratype (ARS-20230808-1e), Madagascar, Ambohitantely Spec. Res, 19.IV.2011, 18°11′48,9″S, 47°17′10,5″E, 1602 m a.s.l., sifting leaf litter under palm tree, leg. L.S. Rahanitriniaina, R. Raveloson. One deutonymph paratype (ARS-20230808-1d) with the same data as holotype except 18°10′51,7″S, 47°17′21,6″E, 1593 m a.s.l., leg. R. Raveloson and one deutonymph paratype (ARS-20230808-1f) with the same data as holotype except 18°11′11,0″S, 47°17′08,5″E, 1624 m a.s.l., leg. L.S. Rahanitriniaina. The holotype and two paratypes (ARS-20230808-1b & 1f) are deposited in the Acarological Collection, Jalal Afshar Zoological Museum, Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj, Iran, and the other three paratypes are deposited in the Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, České Budějovice, Czech Republic.

Caeculisoma madagascarensis n. sp.

ZOOBANK: 57B72050-D179-4A98-BD3F-5F9D97E2A481

Description

Adult female (n = 5)

Idiosoma (Figures 15a & 16a) - Length: 1912 (2092–2543), width, 1616 (1700–2008). Color is not recorded in life but after clearing and mounting yellow to dark brown except palps (Figure 15a); one paratype specimen (ARS-20230808-2e) without color. Dorsal idiosoma is covered with leaf-like setae with two different sizes. One short (Figures 15b & 16b–c), 42–76 (39–78); the second one long with strong median shaft 101–234 (99–243) (Figures 15b & 16b–c).

The crista metopica (Figure 15c) very long 1488 (1324–1816), extending well beyond the middle of the idiosoma. The anterior sensillary area (Figure 10f) prominent, semi-oval with one pair of smooth ASens 85 (101–129) long, 7 (7–10) AL setae, 92–162 (110–196) long. Anterior process (aP) absent. The posterior sensillary area (Figure 17c) located at approximately the middle of the idiosoma; the distance between the anterior and posterior trichobothria insertions (ISD) 792 (727–860). Posterior sensillary area narrow, with small projections (Figure 17d). The crista extends about 543 (435–740), beyond the base of the PSens. PSens 134 (113–147) similar to ASens and smooth. The distance between eye 376 (414–562) and the center of the crista (OCM) is 188 (207–281); OAS 536 (509–609) distinctly longer than OPS 256 (221–279).

Ventral idiosoma covered with two different types of setae. Ventrolateral setae are similar to the dorsal setae in shape and size but more numerous and with distinct barbs (Figures 16c & 17b2); medioventral setae are short and densely barbed, 30–60 long (Figures 16c & 17b–17b1). Genital opening 270 (234–332) long with two pairs of acetabula and epivalves and centrovalves, covered densely with thin barbed setae (Figure 18b). Acetabula (Figure 18c) placed in most cases on one side (right or left) and only in one paratype (ARS-20230808-2c) on both sides). Anal valves (Figure 18d) oval, 68 (78–94) long, and covered with thin barbed setae.

Gnathosoma covered with anterior crista metopica and setae making it difficult to see details clearly. Subcapitulum (Figure 18a) covered with many barbed setae. Chelicerae very long, narrow, dagger-shaped, retractable into idiosoma, and reach behind coxae IV, emarginate except basal and distal ends (Figure 117e). Palps narrow, and linear. Palpal trochanter can′t be seen due to dense dorsal idiosomal setae and was not measured. The palps (Figure 17f) were measured starting with the femur. All palpal segments covered with short and barbed setae. Odontus small, palp tarsus (Figures 16d–f) with 13 (10–13) ω.

All legs with six articulating segments (femur divided). Leg I the longest and leg II the shortest; Ta I longer and differs from other tarsi in shape (Figures 21e–f). Ta IV similar to Ta II and III but slightly longer. Tubercles: Each Ti I-IV with two sub-distal tubercles 0.79 dorsolateral (dl), 0.83dl (0.77–0.83dl), 0.72dl, 0.76dl (0.72– 0.77), 0.72dl, 0.74dl (0.76–0.86), 0.85dl, 0.85dl (0.80– 0.86dl) respectively (Figure 19f), and two distal tubercles in constrictions; all other segments with one distal tubercle except basifemora and tarsi.

Legs (Figures 20–27) with one type of leaf-like seta with two different sizes similar to those on dorsal idiosoma except coxal fields, tibiae and tarsi. Coxae: Cx I-IV are covered with two types of ventral idiosomal setae. Cx I-III each with a stout ventro-distal L-shaped peg-like seta. Trochanters (a & b in Figures 20, 22, 24 & 26): Number of long setae (> 80 in length with distinct median shaft) on Tr I-IV: 11–19, 11–18, 8–14, 12–23. Basifemora (c & d in Figures 20, 22, 24 & 26): Number of long setae on BFe I-IV: 8–19 + 0–1 nude, 5–10 + 0–1 nude, 6–13, 8–11. Telofemora (c & d in Figures 22 & 24 and e & f in Figures 20 & 26): Number of long setae on TFe I-IV: 19–32, 14–19, 13–20, 16–34; number of theta (θ) on TFe I-IV: 0–1, 0–1, 1–2, 0–3. Genua (e & f in Figures 22 & 24 and a & b in Figures 21 & 27): Number of long setae on Ge I-IV: 18–33, 18–24, 14–25, 23–33. Number of sigma (σ) on Ge I-IV: 17–24, 3–6, 3–9, 6–12. Microsetae present on Ge I-II (Table 4, Figures 18 e & 19b). Tibiae (a & b in Figures 21 & 25 and c & d in Figures 21 & 27): Tibiae with long leaf-like setae with thin body and strong shaft, short leaf-like, barbed setae, and phi (φ). Microsetae (κ) on Ti I-II present (Table 4, Figures 19a & c). Number of long setae on Ti I-IV: 10–15, 7–14, 7–14, 6–15. Number of φ on Ti I-IV: many (> 50), 4–10, 3–7, 1–2. There are two tubercles on 9/10 of the segment, and two distal tubercles in a constriction. There are no setae between these tubercles. Tarsi (c & d in Figures 23 & 25 and e & f in Figures 21 & 27): Ta I longer than other tarsi. Ta I covered with barbed setae, omega (ω), an eupathidium (ζ) and a famulus (ε) (Figures 19d & e). The ω on tarsus I are too many to count. Number of solenidia on Ta II-IV: 6–9, 4–9, 3–8. Ta I-III with short leaf-like setae on dorsal surface.

Measurements are given in Table 3.

Remarks

The new species differs from C. tuberculatum in the dorsal idiosomal setae (vs. setae on tubercles and not as above), CML (1324–1816 vs. ~1900), ISD (730–888 vs. 1100); from C. montanum in the length of body (LB) (1912–2543 vs. 3000), leaf-like dorsal idiosomal setae (with two different sizes vs. uniform size); from C. argus in the leaf-like dorsal idiosomal setae (vs. cylindrical, uniformly thick with serrations), leg I (2803–3339 vs. 2200), leg II (1882–2239 vs. 1560), leg III (1963–2319 vs. 1740), leg IV (2724–3321 vs. 2200); from C. cordipes in the LB (1912–2543 vs. 1710), WB (1616–2008 vs. 995), O-O (376–562 vs. 280), CML (1324–1816 vs. 940), ISD (730–888 vs. 610), AL setae (92–196 vs. ≥ 85), Ta I (L) (375–474 vs. 890^*), Ta IV (L) (210–241 vs. 510^*); from C. sulcatum in WB (1616–2008 vs. 1100), leaf-like dorsal idiosomal setae fan-like and long filiform barbed (vs. sparsely feathered setae and interspersed with long, simple, slender spine); from C. infernale in LB (1912–2543 vs. 1185), WB (1616–2008 vs. 720), leaf-like dorsal idiosomal setae (vs. long, strong spines, all smooth above but strongly spined on outside), leg I (2803–3339 vs. 1515), leg II (1882–2239 vs. 1185), leg III (1963–2319 vs. 1315), leg IV (2724–3321 vs. 1515); from C. nasutum in the LB (1912–2543 vs. 1700), WB (1616–2008 vs. 1050), Ti I (546–693 vs. 350), Ta I (L) (375–474 vs. 310), leaf-like dorsal idiosomal setae (vs. fan-like); from C. johnstoni in the body colour (yellow to dark brown vs. red), leaf-like dorsal idiosomal setae (vs. stout rod-like with strong short serrations), LB (1912–2543 vs. 1380), WB (1616–2008 vs. 812), CML (1324–1816 vs. 800), ISD (730–888 vs. 415), Ti I (546–693 vs. 400), Ta I (L) (375–474 vs. 290), leg I (2803–3339 vs. 2110), leg II (1882–2239 vs. 1300), leg III (1963–2319 vs. 1460), and leg IV (2724–3321 vs. 1950); from C. darwiniense (deutonymph) in the leaf-like dorsal idiosomal setae (vs. tapering, curved, slender and fully barbed); from C. io in the leaf-like dorsal idiosomal setae (vs. cylindrical, uniformly thick with serrations); from C. afrum in leaf-like dorsal idiosomal setae (vs. cylindrical, uniformly thick with serrations), CML (1324–1816 vs. 2000), ASens (85–129 vs. 170), ISD (730–888 vs. 1100), OCM (188–281 vs. 320); from C. haussa in the leaf-likedorsal idiosomal setae (vs. cylindrical, uniformly thick with serrations), LB (1912–2543 vs. 1790), CML (1324–1816 vs. 700), ISD (730–888 vs. 405), Ta I (L) (375–474 vs. 240), Ti I (546–693 vs. 305), Ge I (447–565 vs. 275), Ta II (197–249 vs. 130), Ti II (351–412 vs. 195), Ge II (356–428 vs. 215), Ta III (192–231 vs. 130), Ti III (373–424 vs. 225), Ge III (409–474 vs. 240), Ta IV (L) (210–241 vs. 135), Ti IV (513–630 vs. 280), Ge I (621–730 vs. 320). We were not able to compare our species with C. claviger due to an incomplete description, but Cooreman (1958) reported it had long club-shaped dorsal idiosomal setae. Based on Cooreman's report, the new species differs from C. claviger.

^* Vitzthum (1935) wrote 0.089 µm and 0.051 µm for Ta I and IV, respectively. We suggest the measurements were in millimeters not micrometers.

Etymology

The specific name madagascarensis refers to the place of origin, the Madagascar Island.

Type material

The female holotype (ARS-20230808-2a), from Madagascar, Ambohitantely Spec. Res, 19.IV.2011, 18°11′11,0″S, 47°17′08,5″E, 1624 m a.s.l., sifting leaf litter under Pandanus sp. (Pandanaceae), leg. L.S. Rahanitriniaina. Two female paratypes (ARS-20230808-2c, 2d) with the same data as holotype except for 20.IV.2011, 18°11′31,0″S, 47°17′33,3″E, altitude 1630 m a.s.l., sifting forest litter, leg. L.S. Rahanitriniaina and R. Raveloson; one female paratype (ARS-20230808-2e) with the same data as holotype except 18°11′02,5″S, 47°17′12,9″E, altitude 1577 m a.s.l., sifting forest litter, leg. L.S. Rahanitriniaina and one female paratype (ARS-20230808-2b) from Madagascar, Andasibe National Park, 12.IV.2011, 18°56′2,5″S, 48°25′12,2″E, 951 m a.s.l., sifting leaf litter under Pandanus sp., leg. P. Baňař and R.S. Rahanitriniaina.

The holotype and two paratypes (ARS-20230808-2b & 2c) are deposited in the Acarological Collection, Jalal Afshar Zoological Museum, Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj, Iran, and the other two paratypes are deposited in the Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, České Budějovice, Czech Republic.

Key to species of Caeculisoma of the world (post-larval forms)

1. Dorsal idiosoma with two different types of setae
...... 2

— Dorsal idiosomal setae of uniform shape
...... 3

2. Dorsal idiosoma with fan-like, and barbed filiform setae
...... C. banari

— Dorsal idiosoma with sparsely barbed and nude setae
...... C. sulcatum

3. Dorsal idiosomal setae with two distinctly different sizes
...... 4

— Dorsal idiosomal setae uniform in size
...... 9

4. Dorsal idiosoma with long and strong spine-like setae
...... C. infernale

— Dorsal idiosoma not as above
...... 5

5. The longest dorsal idiosomal setae less than 100 µm, ventral idiosomal setae nude
...... C. haussa

— The longest dorsal idiosomal setae more than 100 µm, ventral idiosomal setae barbed
...... 6

6. Leg I > 2700
...... 7

— Leg I < 2300
...... 8

7. Tibiae with one subdistal tubercle, dorsal idiosoma with cylindrical setae
...... C. afrum

— Tibiae with two subdistal tubercles, dorsal idiosoma with leaf-like setae
...... C. madagascarensis

8. The shortest dorsal idiosomal setae less than 25, the longest dorsal idiosomal setae less than 140 µm
...... C. io

— The shortest dorsal idiosomal setae more than 30, the longest dorsal idiosomal setae more than 180 µm
...... C. argus

9. Dorsal idiosomal setae on tubercles (papillae)
...... C. tuberculatum

— Dorsal idiosomal setae without tubercles
...... 10

10. Dorsal idiosomal setae cylindrical, uniformly thick with serrations
...... C. cordipes

— Dorsal idiosomal setae not as above
...... 11

11. Dorsal idiosomal setae elongate clubbed papillae with short cilia
...... C. claviger

— Dorsal idiosomal setae not as above
...... 12

12. Dorsal idiosomal setae tapering, curved, slender and fully barbed
...... C. darwiniense

— Dorsal idiosomal setae not as above
...... 13

13. Dorsal idiosomal setae stout rod-like with strong short serrations
...... C. johnstoni

— Dorsal idiosomal setae not as above
...... 14

14. Dorsal idiosomal setae short and curved, spiniform with narrow sheath
...... C. montanum

— Dorsal idiosomal setae scale- or leaf-like, with strongly chitinized mid-rib
...... C. nasutum

Discussion

The active postlarval instars of most Caeculisoma species have not been adequately described. Many were minimally described without figures. In addition, the deposition for most types were not mentioned. All previously species described should be re-described. Here, we tried to explain all characters e.g., number of solenidia on leg segments, eupathidia and famulus on Ta I-II, nude setae on leg segments. The most important character for Caeculisoma appear to be the shape of dorsal and ventral idiosomal setae and the leg setae. Some characters seem to have important taxonomic values e.g., number of tubercles on Ti I-IV, number of AL setae on anterior sensillary area and their lengths (See Tables 1–4 for more details). The number of solenidia is highly variable on different segments but it can be used for comparison between species. Also, abnormality in number of setae on leg segments is common. Description of new species will determine what characters are important for future comparisons. It seems all species of Caeculisoma have tubercle(s) on leg segments except on basifemora and tarsi. Also, we presented photographs of two new species to show some characters as they as which may be useful for future comparisons.

Acknowledgments

We are very grateful to Dr. Bruce Halliday (CSIRO, Australia), Dr. Matthew Shaw (SAM, Australia) and Dr. Petar Beron (Bulgaria) for their kind help with sending the photography of some species. We thank to Dr. P. Baňař (Brno, Czech Republic) for long-term cooperation in study of soil invertebrates; and the Moravian Museum in Brno, Czech Republic, which kindly provided material for our study. Also, we would like to thank Dr. Mamy A. Rakotorijaona (Directeur des Opérations, Madagascar National Parks, Antananarivo) and Dr. Dimby Raharinjanahary (Chargé des Bases de données de suivi biodiversité et recherche, Madagascar National Parks, Antananarivo) for supporting joint Czech-Madagascan research project (2009–2014). Samples collected in Madagascar were based on collection permit no. 314/13/MEF/SG/DGF/DCB.SAP/SCB by the Moravian Museum in Brno, and sample exportation to Czech Republic was based on permit no. 028N-EA02/MG14. The presented research was supported by Czech Academy of Sciences (Research Plan No. RVO: 60077344). We are also very thankful to an anonymous reviewer for his/her critical comments and improving English language of the manuscript.

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