Memórias do Instituto Oswaldo Cruz Fundação Oswaldo Cruz, Fiocruz ISSN: 1678-8060 EISSN: 1678-8060 Vol. 92, Num. 1, 1997, pp. 81-83

A New Species of Hexathrombium Cooreman, 1944 Based on Parasitic Larva on Erotylids from Brazil

Ryszard Haitlinger

Department of Zoology, Academy of Agriculture, ul. Cybulskiego 20, 50-205 Wroclaw, Poland

Received 6 May 1996
Accepted 19 August 1996

Code Number:OC97015
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Hexathrombium abirami n. sp. (Acari: Eutrombidiidae) an ectoparasite larvae of Erotylidae (Coleoptera) from Brazil is described. A key to larval Hexathrombium is given.

Key words: Acari - Eutrombidiidae - Hexathrombium abirami - new species - Erotylidae - Brazil

The genus Hexathrombium was created for a species H. spatuliferum from Zaire by Cooreman (1944). Long before the species Trombidium cicindelae was described from French Guiana by Floch and Abonnec (1941). According to Fain and Drugmand (1993) this species also belongs to the genus Hexathrombium. Two other species belonging to this genus are: H. fageli Fain and Drugmand (1993) from Ivory Coast and Ethiopia and H. willisi Southcott (1993) from USA (Oklahoma). Haitlinger (1994) decribed four new species of the genus Beronium Southcott. Three of them in unison with differential diagnosis, given by Southcott (1993), also belong to the genus Hexathrombium (B. marittae Haitlinger from Chile, B. lubomirae Haitlinger from Sumatra and Madagascar and B. sorayae Haitlinger from China). To date the genus Hexathrombium comprises eight species (along with a new species). All these species (as larvae) are associated with Coleoptera, especially with Cicindellidae (H. cicindelae, H. willisi), Carabidae (H. spatuliferum, H. marittae, H. sorayae, H. lubomirae), Staphylinidae (H. fageli) and Erotylidae (H. abirami n. sp.). The species of the Hexathrombium at present are known from Neotropical, Nearctic, Afrotropical and Indoaustralian Regions.

MATERIALS AND METHODS

The examined specimens of Hexathrombium abirami n. sp. were obtained from the collection of Erotylidae (Coleoptera) in the Museum of Natural History, Wroclaw University (MNHWU). Holotype and two paratypes are deposited in MNHWU; further three paratypes are in authors collection in Department of Zoology, Academy of Agriculture, Wroclaw.

Measurements are expressed in micrometers. For the terminology of setae and other morphological characters used, see Southcott (1993).

EUTROMBIDIIDAE Thor, 1935
Hexathrombium abirami n. sp.
(Figs 1-8) Figures 1-8 Hexathrombium abirami n. sp. Fig. 1: idiosoma, dorsal view. Fig. 2: idiosoma, ventral view. Fig. 3: gnathosoma, ventral view. Fig. 4: leg I, tarsus - coxa. Fig. 5: leg II, tarsus - coxa. Fig. 6: leg III, tarsus - coxa. Fig. 7: scutum and scutellum. Fig. 8: palptarsus.

Ventrum also covered by cuticular striae. Between coxae III are two small setae. Beyond coxae III are 14 setae. Among them two lateral setae are thick and barbed, two pygidial setae are relatively long; the remaining ones are spiniform (Fig. 2).

Gnathosoma not clearly seen. Mouth-ring with a number of radial sucker markings (Fig. 3). Palpal tibial claw short with two, blunted tines. Palptarsus with eight nude setae; among them two are long ( Fig. 8).

Leg lengths (including coxae, excluding claws): I - 290 in holotype, 301, 303, 284 in paratypes, II - 258, 258, 244, 254, III - 240, 228, -, 228. Lateral coxala I flatened, slightly bifid; medial coxala I slender, spiniform. Lateral coxalae II and III as coxalae I. Urstigma small, oval.

Leg specialized setae. Leg I. Ta - 1 So, ! Fa; Ti - 2 So; Ge - 1 So. II. Ta - 1 So; Ti - 1 So; Ge - 1 So. III. Ge - 1 So (Figs 4-6).

Leg trochanteralae 1,1,1, femoralae 5,5,4, genualae 5,5.?3, tibialae 8,7,5, tarsalae 14N,1B; 13N,3B; 5N,4B. Metric data of holotype and paratypes are given in Table.

Material: holotype larva, five paratype larvae. Host: undetermined Erotylidae (Coleoptera). Locality: unknown in Brazil.

Remarks: H. abirami n. sp. differs from H. cicindelae (Floch and Abonnec) by shorter Ta I, II and length of legs I,II (calculated basing on figures given by these authors). Differentiate features from other species are given below in a key.

KEY FOR SPECIES DETERMINATION *

1. Coxalae I-II with rounded lobes, not widely divergent...................
........................................ H. willisi Southcott, USA Oklahoma 
-. Coxalae I-II with pointed lobes, widely divergent ................... 2. 

2. Setae QL5 over 100 long, pygidial plate not divided, QW4 over 75.......
............................ H. lubomirae (Haitlinger), Sumatra, Madagascar 
-. Setae QL5 below 100, pygidial plate divided, QW below 75 .............3. 

3. PW below 135, QL below 54, SB below 105 ................................
.........................H. fageli Fain and Drugmand, Ivory Coast, Ethiopia 
-. PW over 135, QL over 54, SB over 105 ................................ 4. 

4. QL5 over 78 ......................................................... 5. 
-. QL5 below 76......................................................... 6. 

5. AP below 38, PL below 24 .................H. sorayae (Haitlinger), China 
-. AP over 42, PL over 28 ....................... H. abirami n. sp., Brazil 

6. QL5 over 65, AP below 50, MA over 84......H.spatuliferum Cooreman, Zaire 
-.QL5 below 65, AP over 54, MA below 84.... H. marittae (Haitlinger), Chile 

* H. cicindelae (Floch and Abonnec) is not keyed on account of lack of
measurements. 

To Dr. M. Kak, Museum of Natural History, Wroclaw University, for the loan of the specimens.

REFERENCES

Cooreman J 1944, Notes et observations sur les acariens III. Bull Mus Roy d'hist nat Belg 20: 1-16.

Fain A, Drugmand D 1993. Notes on the genus Hexanthrombium Cooreman, 1944 (Acari rombidiidae) with description of a new tribe and species from Afrotropical Staphylinidae (Coleoptera). Bull Ann r Belg Ent 124: 121-128

Haitlinger R 1994. Four new larval mites (Acari:Trombidiidae:Eutrombidiinae) ectoparasitic on carabids (Insecta:Coleoptera:Carabidae). Rev Chil Ent 21:47-56.

Southcott RV 1993, revision of the Taxonomy of the Larvae of the subfamily Eutrombidiinae (Acarina:Microtrombidiidae). Invert Tax 7: 885- 959.

Copyright 1996 Fundacao Oswaldo Cruz

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