Limnohalacarus cultellatus Viets, 1940

Bartsch, Ilse, 2018, Freshwater halacarid mites (Acari: Halacaridae) from Madagascar - new records, keys and notes on distribution and biology, Bonn zoological Bulletin 67 (2), pp. 79-99 : 80-82

Limnohalacarus cultellatus Viets, 1940

L. cultellatus Viets, 1940: 194–200 , figs 5–12.

L. cultellatus, Bartsch 2011: 491–493 , fig. 2A–C, 2013a: 204–206, figs 1b–h, 2a–h; Pepato & Dos Santos Costa 2015: 5–7, fig. 4A–I.

L. kakinadus Chatterjee & Chang, 2005: 23–27 , figs 1A– H, 2A–D.

Collecting data. South-eastern Madagascar, Fianarantsoa, Ionilahy, stream draining area Marosaro (S from River Ionilahy ), 220 m, 21°C, 0.072 mS/cm, 12 Aug. 2001, interstitial ( MD 023 ) . – South-eastern Madagascar, Fianarantsoa, Ionilahy, River Ionilahy , 200 m, 23°C, 0.059(11. Aug.)–0.088(13. Aug.) mS/cm, 11/ 13 Aug. 2001, interstitial ( MD 026 ) . – Northern Madagascar, Antsiranana, Antalaha, Marofinaritra , River Andranom- enaheli, upstream confluence with River Ankavia (right affluent below MD 135 ) , 70 m, 22.3°C, 0.009 mS/cm, riffle, 04 Nov. 2001 ( MD136 a) .

Short description ( Fig. 1A–E ). Female: Length of idiosoma 255–290 µm [3]. OC and platelet with gland

pore separated by striated integument ( Fig. 1A ), OC about 1.1 times longer than wide. Corneae and spots with eye pigment lacking. AE, PE and GA separated by striated integument ( Fig. 1B ). Pair of ds-6 present on anal cone (obscured by genital sclerites). GP with four to five pairs of gac, three to four pairs of pgs, genital sclerites with two pairs of sgs. Gnathosoma 1.5–1.7 times longer than wide; pharyngeal plate distinctly removed from basal margin of gnathosoma. Both pairs of maxillary setae slender ( Fig. 1C ). Legs shorter than idiosoma, length ratio leg I:idiosoma 0.7:1. Length of telofemur I 1.8 times the height ( Fig. 1D ). Basifemora I to IV with 4, 3, 2, 1 setae, tibiae I to IV with 7, 6, 7, 6 setae. Tibiae I and II each with one bipectinate seta, tibiae III with two bipectinate ventromedial setae, tibia IV with slender, smooth ventral setae. Claws on leg I slender, apically with few 82 Ilse Bartsch

(8–10) minute tines ( Fig. 1E ), basal lamellar process with four tines.

Male: Not present.

Juveniles: Length of deutonymph, protonymph and larva 240 µm [1], 200 µm [1] and 155 µm [1), respectively. Dorsal aspect similar to that of females. AE of larva with pair of epimeral pores. In nymphs GP and anal plate separated by striated integument, in larvae GP lacking.

Remarks. Limnohalacarus cultellatus can be distinguished from the other African Limnohalacarus species by combination of: dorsal and ventral plates separated and pectines on claws I much more delicate than on claws II to IV. Notes on African Limnohalacarus species are given below.

Biology. At present there is no record of a male, neither from Africa nor from other parts of the world.

One of the females included an ovoid excretory body, 125 µm long, 60 µm wide, the centre (10 µm in diameter) is dark, the margin hyaline and delicately stratified. One of the females held an egg, 50 µm long, 55 µm wide.

Geographical distribution ( Fig. 2 ) (cf. Bartsch 2011,

2013a; Pepato & Dos Santos Costa 2015; Ojeda et al.

2016):

Afrotropical Region. – Madagascar;

Palaearctic Region. Europe: – Hungary;

Oriental Region. – India (Andhra Pradesh);

Nearctic Region. – United States ( Georgia, Wisconsin?);

Neotropical Region. – Brazil (Mato Grosso, Rio Grande do Sul) – Cayman Islands (Grand Cayman) – El Salvador – Mexico (Quintana Roo) – The Netherlands Antilles ( Bonaire, Curaçao) – Venezuela (Margarita Island).

Figures

Fig. 1A–E. Limnohalacarus cultellatus Viets, 1940, female. A. idiosoma, dorsal; B. idiosoma, ventral; C. gnathosoma, ventral; D. leg I, medial; E. tarsus I, medial (lateral setae in broken line, lateral claw omitted). (Scale = 50 µm) (AD, anterior dorsal plate; AE, anterior epimeral plate; ascl, anal sclerite; GA, genitoanal plate; gac, genital acetabula; glp-1 to glp-5, first to fifth gland pore; gscl, genital sclerite; OC, ocular plate; PD, posterior dorsal plate; PE, posterior epimeral plate; ph, pharyngeal plate; ti, tines; I-5, tibia of leg I).

Fig. 2. Records of Limnohalacarus cultellatus Viets, 1940 (black spot) and Limnohalacarus novus Bartsch, 2013 (asterisk).