Occurrence of the mite Acanthonyssus proechimys (Mesostigmata: Macronyssidae) on a spiny rat in Brazil

ABSTRACT

Macronyssid mites are ectoparasites of terrestrial vertebrates. We slide-mounted and re-examined mite material collected in a 1987-1989 expedition to Maracá Ecological Station, Roraima State, Brazil. The specimens were identified as Acanthonyssus proechimys Yunker and Saunders (Mesostigmata: Macronyssidae), which were collected parasitizing a South American spiny rat, Proechimys sp. This represents the first record of Acanthonyssus in Brazil.

KEYWORDS:
mites; ectoparasites; Proechimys; new record

RESUMO

Os ácaros macronissídeos são ectoparasitas de vertebrados terrestres. Nós montamos e reexaminamos material de ácaros coletado em uma expedição entre 1987-1989 à Estação Ecológica de Maracá, Estado de Roraima, Brasil. Os espécimes foram identificados como Acanthonyssus proechimys Yunker e Saunders (Mesostigmata: Macronyssidae), que haviam sido coletados parasitando um echimídeo sul-americano, Proechimys sp. Este é o primeiro registro de Acanthonyssus no Brasil.

PALAVRAS-CHAVE:
ácaros; ectoparasitas; Proechimys; novo registro

The family Macronyssidae Oudemans, 1936 has 35 known genera worldwide (Radovsky 2010; Orlova et al. 2017; Bassini-Silva et al. 2021; Gomes-Almeida and Pepato 2021). The genus AcanthonyssusYunker and Radovsky, 1966 has two valid species: Acanthonyssus dentipes (Strandtmann and Eads, 1947) and Acanthonyssus proechimys Yunker and Saunders, 1973. Acanthonyssus dentipes was described parasitizing hispid cotton rats, Sigmodon hispidus Say & Ord, 1825 (Rodentia: Cricetidae) in Texas state, USA (Strandtmann and Eads 1947), while A. proechimys was described parasitizing the Tome’s spiny rat, Proechimys semispinous Tomes, 1860, the cayenne spiny rat, Proechimys guyannensis (É. Geoffroy, 1803), and an undetermined Proechimys sp. (Rodentia: Echimyidae) in Zulia State, Venezuela (Yunker and and Saunders 1973). Despite the possible specificity to Proechimys, associations of A. proechimys with Heteromys anomalus (Thompson, 1815) (Rodentia: Heteromyidae), S. hispidus, Zygodontomys brevicauda Allen & Chapman, 1893 (Rodentia: Cricetidae), a squirrel, some marsupials, and a bat have been recorded (Yunker and Saunders 1973). So far, A. proechimys has not been recorded outside Venezuela.

The material examined in the present study originated from an expedition to Maracá Ecological Station (3°24’04”N, 61°39’19”W), a fluvial island in Roraima state, northern Brazil, organized and sponsored by the Royal Geographical Society (UK) and Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas State, Brazil, between 1987 and 1989. Ectoparasites including mites were collected from small mammals during this expedition and stored in 70% ethanol at the Ectoparasite Sector of the Department of Parasitology of Universidade Federal de Minas Gerais (UFMG) (Linardi et al. 1991).

Recently, the Acari Collection of Instituto Butantan (IBSP), São Paulo, Brazil, received the expedition material identified as a novel species of the genus Echinonyssus, by Linardi et al. (1991). In order to confirm the identification, we remounted the slides according to the techniques described by Jacinavicius (2013). The specimens were deposited in the IBSP collection. More detailed information on the collection, locality description, and diversity of the hosts have been reported by Linardi et al. (1991) for this material.

These mites were identified using the keys to genera by Radovsky (2010). Unlike what was stated by Linardi et al. (1991), our examination revealed that the material did not represent a new species of Echinonyssus, and was in fact A. proechimys. In addition, we compared the specimens with the original description of A. proechimys (Yunker and Saunders 1973). Images were obtained using an Olympus DP73 digital camera coupled with an Olympus BX43 microscope.

Order Mesostigmata Canestrini, 1891

Family Macronyssidae Oudemans, 1936

Genus Acanthonyssus Yunker and Radovsky, 1966

Diagnosis. Acanthonyssus can be separated from the other genera in Macronyssidae by the following sets of characters: peritremes elongated (Figure 1a); sternal shield wider than long (Figure 1c); presence of a recurved ventral spur in the proximal region of the leg segments Tfe IV, Ge II-IV and Ti IV (Figure 1b); all coxae with ventral spurs, sometimes bifid (Figure 1d).

Figure 1
Morphological details of the females of Acanthonyssus proechimysYunker and Saunders, 1973 (Mesostigmata: Macronyssidae) collected in Maracá Island, Roraima State. A - Dorsal region of the opisthosoma with the peritremes elongated, sinuous. Arrows highlight the peritremes; B - Legs I and II showing the ventral recurved spur in the proximal region of the segments Tfe III, Ge III-IV and Ti IV; C - sternal shield; D - Coxa I and II with ventral spurs. The arrow indicates the ventral spurs of coxae of the legs I and II. Abbreviations: st1 = sternal setae 1; st2 = sternal setae 2; st3 = sternal setae 3. Scale bars: A-B = 20 µm; C-D = 10 µm. This figure is in color in the electronic version.

Acanthonyssus proechimys Yunker and Saunders, 1973

Figure 1

Description. See Yunker and Saunders (1973).

Differential diagnosis. Compared to A. dentipes, A. proechimys has the peritreme starting from the middle of Cx I (Figure 1a), and the st1 not reaching the posterior margin of the sternal shield (Figure 1c).

Descriptive notes. Comparing with the original description, no morphological differences were observed. In order to help the identification of future collected materials, Figure 1 highlights the diagnostic characters of A. proechimys.

Material examined. Three females (IBSP 17074A); Maracá Island, Roraima State, Brazil (3°24’04”N, 61°39’19”W); 10 Jan 1989; ex. Proechimys sp. (Rodentia: Echimyidae); P. M. Linardi coll.

Remarks on distribution. This is the first record for the genus Acanthonyssus, and A. proechimys in particular, in Brazil. Apart from this record from Maracá, no other specific locality record exists for A. proechimys, as the type locality in the original description was broadly defined only as Zulia state, in Venezuela. Yunker and Saunders (1973) state that they collected this species throughout the Venezuelan territory on several rodent hosts, mainly echimyid rodents, but do not mention specific localities. Therefore, the known distribution range of A. proechimys is based on two known locality records (Figure 2). The record described herein from Maracá Island is at a minimum distance of approximately 1400 km from the type locality in Zulia state.

Figure 2
Known geographical distribution of Acanthonyssus proechimysYunker and Saunders, 1973 (Mesostigmata: Macronyssidae). The yellow square represents the type locality, and the red dot is the new record. This figure is in color in the electronic version.

ACKNOWLEDGMENTS

This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP no. 2017/01416-7, 2018/24667-8 and 2020/11755-6 to RB-S; 2019/19853-0 to FCJ). We are also thankful to the support of Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [grant # 402575/2021-0 to FCJ, productivity grant to DMB-B (process # 303802/2021-9), and to MRA (process # 303701/2021-8)]. This study was financed in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil (Finance Code 001).

REFERENCES

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• CITE AS:

  Bassini-Silva, R.; Jacinavicius, F.C.; Castro-Santiago, A.C.; Dowling, A.P.G.; André, M.R.; Linardi, P.M.; Barros-Battesti, D.M. 2022. Occurrence of the mite Acanthonyssus proechimys (Mesostigmata: Macronyssidae) on a spiny rat in Brazil. Acta Amazonica 52: 328-330.

Edited by

ASSOCIATE EDITOR:

Pitágoras C. Bispo

Publication Dates

• Publication in this collection
  05 Dec 2022
• Date of issue
  Oct-Dec 2022

History

• Received
  18 Feb 2022
• Accepted
  08 Sept 2022