Caeculisoma taianensis Jiang, Yi, Xu & Jin, 2025, sp. nov.
Creators: name: Jiang, Yan
name: Yi, Tian-Ci
name: Xu, Si-Yuan
name: Jin, Dao-Chao
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Erythraeidae
Caeculisoma
Caeculisoma taianensis

description: Caeculisoma taianensis sp. nov.
Figs 1, 2, 3, 4
Diagnosis (larva).
ASE nude and posterior to the level of ML, closer to ML than PL; PSE with barbs on the distal one-third; gnathosoma with two pairs of nude hypostomalae; ISD 56–63; Ti I 188–207; Ti III 264–287.
Description.
Dorsum. Idiosoma lateral cuticle of holotype used for drawing broken slide preparation, almost oval, with 30 (fD = 28–30 in paratypes) barbed setae, a pair of setae located between scutum and eyes (Fig. 1 A). Scutum outline pentagonal with rounded angles, length somewhat longer than width, anterior margin slightly concave, anterolateral and posterolateral margins slightly sinuous, posterior margin with small concavity between bases of PSE (Figs 1 A, 2 A, 3). Three pairs of normal setae (AL, ML and PL), and two pairs of sensilla (ASE and PSE) placed on scutum. AL, ML and PL completely barbed, ASE nude, PSE with fine barbs in distal about one-third. ASE placed between ML and PL, and closer to ML than PL, PSE near posterior margin of scutum. PSE much longer than ASE, ML slightly longer than AL and PL, AL slightly longer than PL, one paratype (c) AL equal to PL (Table 2).
Venter. All ventral setae, including coxalae, barbed and with pointed ends (Fig. 1 B). Three pairs of intercoxal setae (1 a, 2 a and 3 a), 2 a longer than 1 a and 3 a, 3 a slightly longer than 1 a (Table 2), 14 setae behind coxae III (fV = 12–14 in paratypes). Five pairs of coxalae (1 b, 2 b 1, 2 b 2, 3 b 1 and 3 b 2), 1 b much longer than the other coxalae, 2 b 1 subequal 3 b 1, 2 b 2 and 3 b 2 subequal, 2 b 1 and 3 b 1 longer than 2 b 2 and 3 b 2, respectively (Table 2). Dorsum of coxa I with a peg-like supracoxal seta (elc I) (Fig. 1 C).
Gnathosoma (Fig. 2 B, C). Dorsal view of the cheliceral base punctated. One pair of galealae (cs) and two pairs of hypostomalae (as and bs) nude; bs longer than cs and much longer than as (Table 2). Hypostomal lip with fimbriation. Palpfemur and palpgenu each with one barbed, pointed dorsal seta (PaScFed and PaScGed). Palptibia with three barbed setae, one on ventral surface, odontus bifid. Palptarsus with seven setae, five nude, one solenidion (ω) and one eupathidium (ζ). fPp = 0 - B-B- 3 B 2 -5 Nωζ. Palpal supracoxal seta (elcp) peg-like.
Legs (Figs 1 B, 3). With seven segments (femora divided). IP = 2533–2692 (Holotype and six paratypes). Claws hook-like and posterior claw with few ciliations, and empodium claw-like. Normal setae on legs barbed and pointed. Leg setal formula: leg I: Cx — 1 n; Tr — 1 n; Bfe — 4 n; Tfe — 5 n; Ge — 1 σ, 1 κ, 12 n; Ti — 2 φ, 1 κ, 1 Cp, 18 n; Ta — 1 ω, 1 ε, 2 ζ, 1 Cp, 27 n. leg II: Cx — 2 n; Tr — 1 n; Bfe — 4 n; Tfe — 5 n; Ge — 1 κ, 12 n; Ti — 2 φ, 19 n; Ta — 1 ω, 1 ζ, 28 n. leg III: Cx — 2 n; Tr — 1 n; Bfe — 2 n; Tfe — 5 n; Ge — 12 n; Ti — 1 φ, 19 n; Ta — 1 ζ, 28 n. The morphometric data of the legs is listed in Table 2.
Etymology.
The new species’ name is derived from Taian Town, where the holotype and paratype were collected.
Material examined.
Holotype. China • a larva (1087–0275-YN-yl); Yunnan Province, Yulong County, Taian Town; 26°37'8"N, 100°02'9"E; 2502 m; 8 Aug. 2021; Yan Jiang leg.; from Atkinsoniella sp. (Hemiptera, Cicadellidae). Paratypes China • one larva (1088–0275-YN-yl), same data as the holotype. China • three larvae (1082–0271-YN-yl, 1083–0271-YN-yl, 1084–0271-YN-yl); Yunnan Province, Yulong County, Taian Town; 26°37'8"N, 100°02'9"E; 2502 m; 8 Aug. 2021; Yan Jiang leg.; from unidentified Atkinsoniella (Hemiptera: Cicadellidae). China • one larva (1085–0272-YN-yl); Yunnan Province, Yulong County, Taian Town; 26°37'8"N, 100°02'9"E; 2502 m; 8 Aug. 2021; Yan Jiang leg.; from an unknown nymph of Cicadellidae. China • one larva (1086–0273-YN-yl); Yunnan Province, Yulong County, Taian Town; 26°37'8"N, 100°02'9"E; 2502 m; 8 Aug. 2021; Yan Jiang leg.; from an unidentified nymph of Cicadellidae.
The holotype and paratypes are deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC).
Remarks.
Based on the description of larvae, the genus Caeculisoma includes 13 species so far; of them, four species are from Australia and four from China, two species are from Brazil, while the remaining three species are found in Iran, the Republic of South Africa and New Zealand, respectively (Mąkol and Wohltmann 2012; Xu et al. 2020; Kohansal et al. 2024; Noei et al. 2024).
Similar species to C. taianensis sp. nov. are currently known as C. darwiniense Southcott, 1961, C. mouldsi Southcott, 1988, C. pouyani Noei & Kohansal, 2024 and C. sparnoni Southcott, 1972 based on the key to species of Caeculisoma in Kohansal et al. (2024).
The new species differs from C. darwiniense by the shape of ASE (nude vs barbed), posterior hypostomalae (bs) (nude vs barbed), galealae (cs) (nude vs barbed), the number of normal setae on fn Ge I – III (12-12 - 12 vs 11-12 - 13), the number of normal setae on fn Ti I – III (18-19 - 19 vs 17-18 - 20), longer L (103–114 vs 87–88), Ti I (188–207 vs 102), and Ti III (264–287 vs 143); differs from C. mouldsi by the shape of ASE (nude vs barbed), shape of posterior hypostomalae (nude vs barbed), gnathosoma with two pairs hypostomalae (vs one pair hypostomalae), the number of normal setae on fn Ge I – III (12-12 - 12 vs 12-11 - 12), the number of normal setae on fn Ti I – III (18-19 - 19 vs 18-19 - 18), longer 1 b (64–74 vs 37–58), PaScFed (73–85 vs 42), leg II (800–855 vs 750), leg III (952–1010 vs 915), IP (2533–2692 vs 2455); differs from C. pouyani by the shape of ASE (nude vs barbed), galealae (nude vs barbed), hypostomalae (nude vs barbed), palp tarsus with five nude normal setae (vs with five barbed normal setae), longer W (97–108 vs 75–87), 1 b (64–74 vs 40–46), Ti I (188–207 vs 85–95), Ti II (194–216 vs 85–92), Ti III (264–287 vs 115–130), IP (2533–2692 vs 1360–1505) and differs from C. sparnoni by shape of ASE (nude vs barbed), cheliceral bases without striations (vs with lengthwise striations), longer L (103–114 vs 83), W (97–108 vs 85), 1 b (64–74 vs 28), Ta I (150–160 vs 77), Ti I (188–207 vs 83), Ta III (165–176 vs 79), Ti III (264–287 vs 100), IP (2533–2692 vs 1220).
The differences between the new species and the four present species of Caeculisoma found in China are as follows: C. taianensis sp. nov. differs from C. allopenlineatus by the positions of ASE (ASE closer to ML than PL vs ASE closer to PL than ML), shape of scutum (pentagonal vs oval), ASE (nude vs barbed), the longer Ti I (188–207 vs 164–170), Ti II (194–216 vs 151–161), Ti III (264–287 vs 227–239), IP (2533–2692 vs 2061–2115), the shorter ML (46–51 vs 114–120); differs from C. hunanica by the number of solenidia on Ti II (2 vs 1), the number of normal setae on TFe III (5 vs 4), the number of normal setae on fn Ti I – III (18-19 - 19 vs 16-16 - 18), longer leg I (781–834 vs 655), leg II (800–855 vs 621), leg III (952–1010 vs 728), IP (2533–2692 vs 2004); differs from C. penlineatus by ASE base location (closer to ML than PL vs in line with the level of PL), BFe I and II with four barbed setae (vs with three barbed setae and one nude seta), palptarsus with one eupathidium (vs with two eupathidia), longer Ti I (188–207 vs 143–167), Ti II (194–216 vs 150–179), Ti III (264–287 vs 213–239), leg I (781–834 vs 627–709), leg II (800–855 vs 645–724), leg III (952–1010 vs 768–878), IP (2533–2692 vs 2060–2298), data based on Xu et al. (2019 b, 2020) and differs from C. semispinus by the shape of ASE (nude vs with barbs on distal halves), palptibia with three barbed setae (vs with one barbed seta and two nude setae), palptarsus with five nude setae (vs with two barbed setae and three nude setae), longer L (103–114 vs 78–84), W (97–108 vs 71–80), ISD (56–63 vs 41–44), Ti I (188–207 vs 149–163), Ti III (264–287 vs 213–227), IP (2533–2692 vs 2041–2100).
description: Published as part of Jiang, Yan, Yi, Tian-Ci, Xu, Si-Yuan & Jin, Dao-Chao, 2025, Two new species of larval Erythraeidae (Parasitengona) ectoparasites of leafhoppers from Southwestern China, pp. 85-101 in ZooKeys 1236 on pages 85-101, DOI: 10.3897/zookeys.1236.139274