Caeculisoma penlineatus Xu & Jin, 2019

Xu, Si-Yuan, Yi, Tian-Ci, Guo, Jian-Jun & Jin, Dao-Chao, 2019, A new species of larval Caeculisoma (Acari: Erythraeidae: Callidosomatinae) ectoparasitic on insects from China and a revised generic diagnosis, Zootaxa 4604 (3), pp. 511-524 : 512-522

publication ID	https://doi.org/ 10.11646/zootaxa.4604.3.7
publication LSID	lsid:zoobank.org:pub:4C16850A-E6C0-4959-9B9B-15AE7001009B
persistent identifier	https://treatment.plazi.org/id/EA394B65-775D-8D4B-87CA-FB60EDDBFEB3
treatment provided by	Plazi
scientific name	Caeculisoma penlineatus Xu & Jin
status	sp. nov.

Treatment

Caeculisoma penlineatus Xu & Jin sp. nov.

( Figs. 1 View FIGURE 1 ̅12)

Diagnosis (larva). ASE anterior to PL bases and very close to PL bases; palptarsus with two eupathidia; fnBFe = 4-4-2; fnTFe = 5-5-5; fnGe = 12-12-12; fnTi = (16̅18) - (17̅19) - (17̅19); Ti III 222 ̅236; Ti II 151 ̅166; Ti I 149̅164; ISD 34̅47; posterior sensillae (PSE) with fine barbs on distal halves.

Description. Dorsum. Idiosoma almost oval, with 30 (fD=25̅ 32 in paratypes) barbed setae, a pair of setae located between scutum and eyes at level with PSE bases ( Fig. 1 View FIGURE 1 ). Scutum semi-pentagonal, somewhat longer than wide, with rounded angles, anterior margin slightly concave medially. Lateral margin rounded, posterolateral margin sinuous with small concavity between bases of PSE ( Fig. 3 View FIGURE 3 ). Scutum with three pairs of normal setae (AL, ML and PL) and two pairs of sensilla (ASE and PSE) subequal in length ( Fig. 3 View FIGURE 3 ) ( Table 3 View TABLE 3 ). ML longer than AL and PL, AL and PL subequal in length, both completely barbed, AW <MW <PW ( Table 3 View TABLE 3 ). ASE nude, very close to level of PL bases ( Fig. 3 View FIGURE 3 ). PSE barbed in distal half, on posterior margin of scutum.

Venter.All ventral setae, including coxalae, barbed, with pointed ends ( Fig. 2 View FIGURE 2 ). One pair of intercoxal setae (1a) between coxae I, one pair of intercoxal setae (2a) between coxae I, and one pair of intercoxal setae (3a) almost at a line with anterior edges of coxae III, seven pairs of setae behind coxae III (fV=5̅7 pairs). Sternalae 2a longer than 1a and 3a, 1a and 3a subequal. Coxalae 1b longer than other coxal setae and the setae on coxae II & III nearly equivalent in length ( Fig. 2 View FIGURE 2 ). NDV= 36̅44.

Gnathosoma with a pair of nude galealae (cs), a pair of nude anterior hypostomalae (as) and a pair of nude posterior hypostomalae (bs) ( Fig. 4 View FIGURES 4 ); bs longer than as ( Table 3 View TABLE 3 ). Hypostomal lip fimbriated like a garland. Palpfemur and palpgenu each with one barbed, pointed dorsal seta. Palptibia with one nude ventral seta, one nude dorsal seta, and one barbed, pointed dorsal seta; palpal tibial claws bifid ( Fig. 4 View FIGURES 4 ). Palptarsus with seven setae, of which three barbed, one nude, one solenidion and two eupathidia ( Figs. 4 View FIGURES 4 ̅6). fPp = 0-B-B-BNN 2 -BBBNωζζ. Palpal supracoxal seta (eP) peg like.

Legs with six free segments (femora subdivided). IP= 2113̅2261 (Holotype and five paratypes). Pedal ba- sifemur I & II with one nude, thin seta much longer than other pedal normal setae ( Fig. 7 View FIGURES 7 ̅10). Tarsus I with one long and pointed solenidion (ω I), tarsus II with one solenidion (ω II) ending bluntly. Normal setae on legs barbed and pointed. Leg setae formula (Holotype): Leg I: Cx—1n; Tr—1n; Bfe—4n (3B, N); Tfe—5n; Ge—1σ, 1κ, 12n; Ti—2φ, 1κ,18n; Ta—1ω, 1ε, 2ζ, 26n, ω long (71 μm). Leg II: Cx—2n; Tr—1n; Bfe—4n (3B, N); Tfe—5n; Ge—1κ, 12n; Ti—2φ, 19n; Ta—1ω, 1ζ, 28n. Leg III: Cx—2n; Tr—1n; Bfe—2n; Tfe—5n; Ge—12n; Ti—1φ, 19n; Ta—27n ( Figs. 2 View FIGURE 2 , 7 View FIGURES 7 ̅12). The leg setae formula of paratypes are given in Table 2 View TABLE 2 .

Remarks. From a morphological perspective, six specimens are identical and indistinguishable although the normal setae of Ti I-III have asymmetric chaetotaxy sets in two specimens: Four specimens are fnTi I-III = 18- 19-19; another two specimens, from Chongqing Municipality and Hainan Province (3p and 4p), are fnTi I–III = 18-19-19 on one side and fnTi I–III = 16-17-17 on the other side. The difference in leg setae formula is evidently individual variation.

Etymology. The name penlineatus is alludes to the position of ASE, which is in line with the level of PL, and is derived from pen (itself derived from pennus).

Types. Holotype, larva, unidentified Issidae (Hemiptera) , collected by Xin-Feng Zhang on 28 April 2009, from Bawangling National Natural Reserve , Hainan Province, China . Paratypes: one larva, unknown Hemipteran insect collected by Xin-Feng Zhang on 27 April 2009, from Bawangling National Natural Reserve , Hainan Province, China ; one larva, ex Mileewa margheritae (female) ( Hemiptera : Cicadellidae : Mileewinae ), one larva, ex Alebrini ( Hemiptera : Cicadellidae : Typhlocybinae ) and one larva, unidentified Delphacinae ( Hemiptera : Delphacidae ) collected by Si-Yuan Xu on 6 August 2015, from Fairy Mountain National Forest Park, Chongqing Municipality, China; one larva, ex Delphacinae ( Hemiptera : Delphacidae ), collected by Guang-Yu Liu, on 1 August 2014 from Fanjingshan National Natural Reserve, Guizhou Province, China. The holotype and all paratypes are deposited in Institute of Entomology, Guizhou University, Guiyang, China (GUGC) ( Zhang 2018).

Differential diagnosis. Eight species known based on larvae in genus Caeculisoma , as follows: Caeculisoma carmenae Haitlinger, 2008 , Caeculisoma cooremani Southcott, 1972 , Caeculisoma darwiniense Southcott, 1961 , Caeculisoma hunanica Zheng, 2002 , Caeculisoma huxleyi Southcott, 1972 , Caeculisoma mouldsi Southcott, 1988 , Caeculisoma nestori Haitlinger, 2004 , Caeculisoma sparnoni Southcott, 1972 ( Haitlinger 2004, 2008; Southcott 1961a, 1972, 1988b; Zheng 2002).

Caeculisoma penlineatus sp. nov. can be separated from all other species based on the position of ASE, which are in line with the level of PL. In all other species, ASE is anterior to the level of PL (but still behind the level of ML). In this regard, C. cooremani is the closest species, which as ASE almost in line with PL. Caeculisoma penlineatus sp. nov. differs from C. cooremani by the number of ventral setae between coxae II̅III (2 vs. 4), and the longer Ta I (141̅150 vs. 63̅83), Ti I (149̅164 vs. 63̅83), Ti III (222̅236 vs. 104), L (100̅114 vs. 79̅84) and W (109̅126 vs. 73̅86).