Quadraseta brasiliensis Goff and Gettinger, 1989

Jacinavicius, F. C., Bassini-Silva, R., Mendoza-Roldan, J. A., Muñoz-Leal, S., Hingst-Zaher, E., Ochoa, R., Bauchan, G. R. & Barros-Battesti, D. M., 2018, A contribution to the knowledge of Quadraseta brasiliensis Goff and Gettinger, 1989 (Trombidiformes: Trombiculidae), with description of the deutonymph instar, Acarologia 1989 (2), pp. 442-456 : 444-452

Quadraseta brasiliensis Goff and Gettinger, 1989

Quadraseta brasiliensis Goff and Gettinger, 1989: 557 .

Diagnosis — Larva. ( Figures 1 , 2 and 3A ; Table 1) Palpal tibia setae branched, galeal setae nude, claviform trichobothria, 2 humeral setae, the first row of idiosomal dorsal setae are arranged in line with 8 setae, genu of leg I with 3 solenidia, the base of microseta is proximal to the base of solenidion on the tarsus of leg I.

Deutonymph. ( Figures 4 and 5 , Table 2) Sternal area with five branched setae on one side and four branched setae on the other side between coxae I; 8 distinct but minute dorsal teeth in cheliceral each blade, palp tibia with 5 setae branched and 1 dorsal nude seta; base of tibial claw flanked by 2 spoon-shaped accessory setae, palp tarsus with 7 branched setae, 2 nude apical sensory setae, a leaf-shaped tectum, with a single tectal seta, parascutal setae number approximately six on either side of crista, typically arranged at 2-4; three pairs of branched epivalval setae and six pairs of branched centrovalval setae.

Redescription — Larva. Yellowish-white colored when alive. Gnathosoma ( Figure 1A and

B, 2C ) – palpal setal formula B/B/BBB/4B, B = branched seta on the femur; B = branched seta on genu; BBB = branched dorsal, ventral setae, and lateral tibial setae, respectively 4B = four branched with ω on tarsus; odontus trifurcate; cheliceral blade with tricuspid cap; gnathobase punctate, galeal nude setae. Idiosoma – eyes 2/2; anterior larger, on ocular plate, scutum with 1 pair of AL, 1 pair of PL and a single AM seta, PL> AM> AL; 1 pair of claviform trichobothria, covered with setules; scutum with concave lateral margins, posterior margin with =

– Leg I; E – Leg II; F – Leg III; G – dorsal view of idiosoma; H – ventral view of idiosoma. Black spots = ventral setae of the idiosoma; white spots = dorsal setae of the idiosoma. Symbols: ω = solenidion of palpal tarsus; AL = anterolateral seta on scutum; PL = posterolateral seta on scutum; AM = anteromedial seta on scutum; S = trichobothria; σ = solenidion of the genu I, II and III; κ = microsetae on genu and tibia; Φ solenidion of the tibia I, II and III; ω = solenidion I and II; ε = famulus I and II; ζ = dorsal eupathid I, subterminal eupathid of the legs I and

II;

z = companion seta of dorsal eupathid on the leg I; 1a = anterior sternal setae; 3a = posterior sternal setae. Scales: A-F 50 μm; G-H 100 μm.

two smooth evaginations and anterior margin with two invaginations both turned to the base of trichobothria, as figure 1C, 2E and F. Ninety-four idiosomal setae (material range 84-97 setae), including 1 pair of humeral, 1 st row of dorsal idiosomal setae with 8 setae, nd 2 row with 8 setae,

3 rdrow with 8 setae, 4 th row with 11 setae and 5 th row with 13 setae, totaling 48 dorsal setae (material range 39-48 setae), 2 pairs of sternal, and 26 preanals and 14 postanals, totalizing 40 ventral setae (material range 40-47 setae) ( Figures 1H and G , 2D ). Legs – seven-segmented, femur divided in basifemur and telofemur, with a pair of claws and a clawlike empodium, onychotriches absent, coxae not striate. Leg I – coxa with 1 branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, σ 3, with κ; tibia 8B, Φ 2, with κ; tarsus 21B, with ω, ε, dorsal eupathid (ζ) with a companion seta (z) and subterminal eupathid (ζ), base of ε proximal to base of ω ( Figure 1D , 2A and B ). Leg II – coxa 1B; trochanter 1B; basifemur 2B; telofemur 4B;

genu 3B, σ; tibia 6B, Φ 2; tarsus 16B, with ω, ε, and subterminal eupathid, base of ε proximal to base of ω ( Figure 1E ). Leg III – coxa 1B on anterior margin, trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, σ, tibia 6B, Φ; tarsus 15B ( Figure 1F ). The morphometric data are shown in Table 1.

Description — Deutonymph. Dorsal idiosoma – color whitish yellow, eyes absent; The entire body with branched setae on plates, shown in Figure 4B; a leaf-shaped tectum, with a single tectal seta; six parascutal setae on either side of crista, typically arranged at 2-4 ( Figure 4C ); trichobothria long and slender, proximal portion with numerous short branches, and the distal portion with numerous long thin branches ( Figure 4C and E ). Ventral idiosoma –

Sternal area: with five branched setae on one side and four branched setae on the other side between coxae; six pairs of branched epivalval setae, 2 pairs of oval acetabula present, posterior acetabulum smaller than anterior and three pairs of branched centrovalval setae ( Figure 4D ); a pair of anal plates, each one with eight branched setae ( Figure 4D ). Gnathosoma – Cheliceral blade straight, V-shaped, with 8 distinct but minute dorsal teeth, along each. Entire hypostome not divided into lobes, with 4 pairs of nude apical setae; palp femur with 8 branched setae; palp genu with 7 branched setae; palp tibia with 5 setae branched and 1 dorsal nude seta; base of tibial claw flanked by 2 spoon-shaped accessory setae; palp tarsus with 8 branched setae, 2 nude apical sensory setae (ζ) and 1 basal sensory rod (ω) ( Figure 4F ). Legs – seven-segmented, femur divided in basifemur and telofemur, tarsi with a pair of claws, onychotriches absent; leg I and IV longer than legs II and III; tarsus I oblong in shape, inflated, always longer than tibia I ( Figure 4A ). All leg segments densely covered with normal setulated setae and the specialized setae present on leg I (tFe–Ta), II (tFe-Ta), III (tFe-Ta), IV (Ge–Ta) ( Figure 5 A-F). The morphometric data are shown in Table 2.

Remarks — The species Q. brasiliensis resembles the species Q. pazca and Q. mackenziei ( Yunker and Brennan, 1964) , but is has the first row of dorsal idiosomal setae in lines and the all palpal tibia setae branched. The species Q. brasiliensis differs from the other species in presents

8 setae in the first row of idiosomal dorsal setae, while the other two species have 10 setae. Q.

brasiliensis and Q. mackenziei has galeal nude setae, while Q. pazca has galeal branched setae.

The trichobothria in Q. brasiliensis and Q. pazca are clavate, while in Q. mackenziei are globose.

Biology — In laboratory conditions, engorged larvae, recently collected from the hosts, kept in Petri dishes with substrate (1:1), remained active for 1-3 days. After this period the larvae enter in the process of quiescence (protonymph), at this stage there is an extrusion of the legs. This process lasted 7-11 days and a deutonymph emerged from the anterior dorsal portion of protonymph, the deutonymphs remained alive for up to 20 days without feeding.

New records ( Figure 6 ) — BRAZIL – 6 larvae, Fazenda Água Limpa ( FAL), Brasilia – Federal District, (15°56′45′′S, 47°56′8′′W), 21-V-1984, H. megacephalus ( DG494 ) ; 10 larvae,

same locality, 24-V-1984, Monodelphis americana ( DG498 ) ; 10 larvae, same locality and host ( DG515 ), 16-VI-1984 ; 10 larvae, same locality, 21-II-1984, Monodelphis sp. ( DG260 ) ; 10

larvae, same locality, 22-IV-1984, H. megacephalus ( DG394 ) ; 10, same locality, 24-II-1984, H. megacephalus (#102) ; 10 larvae, Reserva Ecológica do Instituto Brasileiro de Geografia e Estatística ( IBGE) (15°56′41′′S, 47°53′07′′W), 8-VII-1984, no host information (#37) ; 1 larva

(IBSP 1154), Serra da Cantareira , São Paulo, state of São Paulo (23°22′44′′S, 46°31′38′′W), 8- IX-1937, Cuniculus paca, Navas J. coll .; 8 larvae ( IBSP 10390 ), Adrianópolis , state of Paraná (24°39′25′′S, 48°59′27′′W) 12-IX-2009, Euryoryzomys russatus ; 1 larva ( IBSP10521 A), Zoológico de São Paulo, São Paulo, state of São Paulo (23°38′57.49′′S, 46°37′19.76′′W), 16-IV-2010, Akodon sp .; 1 larva ( IBSP 10522 ), Barra do Una, Peruíbe , state of São Paulo (24°19′12′′S, 46°59′52′′W), 8-XI-2010, Euryoryzomys russatus ; 2 larvae ( IBSP 10524 A), same locality and host, 18-VI-2010 ; 1 larva ( IBSP 10525 A), same data ; 2 larvae ( IBSP 10526 A) ,

same locality and host, 16-VI-2010 ; 4 larvae ( IBSP 10527 A), same data ; 1 larva ( IBSP 10528 ), same locality and host, 7-XI-2010 ; 2 larvae ( IBSP 10529 ), same locality and host, 21-IV-2010 ;

2 larvae ( IBSP 10530 ), same locality and host, 20-IV-2010 ; 2 larvae ( IBSP 10531 ), same locality and host, 21-IV-2010 ; 3 larvae ( IBSP 10532 ), same data ; 3 larvae ( IBSP 10533 A) ,

same locality and host, 19-IV-2010 ; 5 larvae ( IBSP 10535 A), Serra da Cantareira , São Paulo ,

state of São Paulo, same host, 12-IV-2011 ; 2 larvae ( IBSP10536 ), same locality and host, 14-IV-2011 ; 10 larvas ( IBSP 10537 ), same data ; 3 larvae ( IBSP10538 ), same locality and host, 18-XII-2010 ; 4 larvae ( IBSP 10540 ), same locality and host, 17-II-2010 ; 1 larva ( IBSP 10590 D), Condomínio Vila Verde, Itapevi , state of São Paulo, (23°32′56′′S, 46°56′02′′W), 12to16-XII-2011, Didelphis aurita ; 6 larvae ( IBSP 11096 G), Morro Grande, Cotia , state of São Paulo (23°38′58.12′′, 46°57′45.99′′W), 20-VI-2012, Euryoryzomys russatus ; 9 larvae ( IBSP 11116 B), Condomínio Vila Verde, Itapevi , state of São Paulo, 29-XI-2012, Monodelphis sp .; 1 larva ( IBSP 11130 ), Morro Grande, Cotia , state of São Paulo, 22-VII-2012, Monodelphis sp .; 2 larvae ( IBSP11131 ), same locality, 19-X-2012, Euryoryzomys russatus ; 1 larva ( IBSP 11132 ) ,

same locality, 23-VII-2012, Thaptomys nigrita ; 1 larva ( IBSP 11178 C), same locality, Akodon montensis ; 4 larvae ( IBSP 11259 C), same locality, 18-IV-2013, Euryoryzomys russatus ; 2

larvae ( IBSP 11303 C), Sete Barras , state of São Paulo (24°23′16′′S, 47°55′33′′W), 20-IV-2013, Oligoryzomys nigripes ; 2 larvae ( IBSP 11304 A), same locality, 20-IV-2013, Oligoryzomys sp .;

2 larvae ( IBSP 11305 ), same locality, 10-VIII-2013, Euryoryzomys russatus ; 1 larva ( IBSP 11365 ), same data ; 4 larvae ( IBSP 11366 ), same locality, 10-VIII-2013, Monodelphis iheringi ;

2 larvae ( IBSP 11367 ), same locality, 15-VIII-2013, Oxymycterus sp .; 2 larvae ( IBSP 11369 ) ,

same locality, no date, Delomys sp .; 1 skin of larva and 3 deutonymphs ( IBSP 12138 B), Morro Grande, Cotia , state of São Paulo, no date, Euryoryzomys russatus ; 1 skin of larva and 3 deutonymphs ( IBSP 12140 ), same locality, no date, Akodon sp .; 1 deutonymph ( IBSP 12141 ), same locality, no date and host information ; 1 skin of larva ( IBSP 12144 ), same locality, 15-IV-2015, Akodon sp .; 3 skins of larva and 3 deutonymphs ( IBSP 12146 A), same locality and date, Monodelphis sp .; 2 skins of larva and 2 deutonymphs ( IBSP 12554 A), same locality ,

no date and host information; 27 larvae, 15 skins of larva and 11 deutonymphs ( IBSP 12557 B), same locality, 20-VIII-2015, Akodon montensis ; 4 skins of larva ( IBSP 12559 ), same locality ,

no date and host information; 12 skins of larva (IBSP 12560), same locality, no date and host information; 1 skin of larva (IBSP 12695), 23-X-2013, Thaptomys nigrita .

Molecular analyses

Although expected size amplicons were obtained for 14/24 of the samples submitted to PCR, only three larvae and two deutonymphs yielded bands strong enough for sequencing. After an alignment of 421-bp including these five sequences, two haplotypes differing in one nucleotide were observed: one belonging to the deutonymphs and two larvae (GenBank accession numbers: KY934462 , KY934464 , MF113412 and MF113413 ), and another to one larva ( KY934463 ). By BLAST analyses, both haplotypes of Q. brasiliensis were 96 – 99% similar to the sequences available in GenBank for Allothrombium sp. ( KP276493 ) and Eutrombicula splendens ( Ewing, 1913) ( KP325057 ) respectively. For the gene COI, none of the tested samples amplified.

Figures

Figure 1 Morphological details ofQuadraseta brasiliensis: A – ventral view of palpal tarsus; B – dorsal view of gnathosoma; C – scutum; D

Figure 2 Scanning electron micrographs of Quadraseta brasiliensislarvae: a – Tarsus of the leg I; b – details of the specialized setae of tibia and tarsus of the leg I (in the small box striations of the solenidion of the tarsus of the leg I); c – ventral view of the gnathosoma; d – idiosomal dorsum; e – scutum; f – details of the trichobothria.

Figure 3 Low-temperature scanning electron micrographs of Quadraseta brasiliensis: A – frontal view of larva; B – lateral view of deutonymph.

Figure 4 Low-temperature scanning electron micrographs of Quadraseta brasiliensisdeutonymph: a – general view of the palp, leg I and II; b – idiosomal dorsal setae; c – crista metopica; d – genital area and anal plates; e – trichobothrium; f – palpal tarsus and palpal tibia.

Figure 5 Low-temperature scanning electron micrographs of Quadraseta brasiliensisdeutonymph. Details of the deutonymphs’ setae: a – branched setae of the genu on the leg I; b – solenidion of the genu on the leg I; c – microseta of the genu on the leg I; d – solenidion of the genu on the leg I; e – solenidion of the femur on the leg I; f – solenidion of the tibia on the leg I.

Figure 6 Geographical distribution ofQuadraseta brasiliensis.