Arphthicarus rectus Niedbała, 2019

NiedbaŁa, Wojciech & Ermilov, Sergey G., 2019, Three New Species Of Steganacaridae (Acari, Oribatida) From Zanzibar, Acta Zoologica Academiae Scientiarum Hungaricae 65 (3), pp. 243-251 : 248-250

Arphthicarus rectus Niedbała sp. n.

( Fig. 3A–G)

Measurements. Specieswithrathersmallbodysize. Holotype. Prodorsum: length 195, width 144, height 76. Prodorsalsetae: ss 73, in 61, ro 35. Notogaster: length 374, width 257, height 232. Notogastralsetae: c 1 53, c 1 / c 1 – d 1 =0.65, d 1, e 1, h 1 40, ps 2 34. Genito- aggenital plate 101 × 96. Ano- adanalplate 162 × 104. Measurementsofparatypes. Prodorsum: length 157–195, height 56–66. Notogaster: length 273–384, height 167–227.

Integument. Colourlightbrown. Bodysurfacecoveredwithdeepconcavities.

Prodorsum. Lateralcarinaeabsent. Posteriorfurrowspresent. Sigillarfieldsshort, medianfieldlarge. Sensillilong, slightlysickle- shaped, withnarrowlyfusiformhead coveredwithsmallcilia. Interlamellarsetaeratherlong, erect, robust, coveredwithsmall spinesindistalhalf, similartonotogastralsetae. Lamellarandexobothridialsetaevestigial. Rostralsetaeerect, removedfromeachother, pointeddistally, rough. Relativelengthof setae: ss> in> ro.

Notogasterwith 15 pairsofrigid, rathershort (c 1 <c 1 – d 1), distallyslightlyobtuse (visibleunderhighmagnification) setaecoveredwithsmallspinesindistalhalf. Dorsalsetae slightlylongerthanlaterals. Setae c 1 and c 3 slightlyremotefromanteriormargin, setae c 1 morethan c 3; c 2 muchdistantfrommargin. Vestigialsetae f 1 locatedslightlyposteriorlyof h 1. Allfourpairsoflyrifissures (ia, im, ip and ips) present.

bars 100 μm (A, B), 50 μm (E, F), 25 μm (C, D, G)

Ventralregion. Setae h ofsubcapitulumconsiderablylongerthandistancebetween them. Arrangementofgenitalsetae: 6(4+2): 3. Ano- adanalplatewithfivepairsofsetae, ad 2 coveredwithsmallspinesindistalhalf, longestandthickest, analsetaesmallest.

Legs. Formulasofsetaeandsolenidiaof “completetype” ( NIEDBAŁA 2000). Setae d on femoraIcurveddistally, slightlyremotefromdistalendofarticle.

Holotypeand 7 paratypes: Tanzania, Zanzibar, litterinthemixedforest, 06°16‘46.2“S, 039°25‘41.0“E, 8 m a.s.l., 2.II.2018 (A. A. Khaustov & S. G. Ermilov) .

Typedeposition. Theholotypeand 7 paratypes (allinethanolwithdropofglycerol) aredepositedinDATE.

Etymology. ThespecificepithetofthenewspeciesisderivedfromLatin rectus and alludestoerectinterlamellarandrostralsetae.

Remarks. Thenewspeciesissimilarto Arphthicarusethiopicus Niedbała, 2008 fromEthiopiabytheshapeandlengthofsensilliandnotogastralsetae, widelyspacedrostralsetae, numberandlocationoflyrifissures, locationof vestigialsetae f 1, shapeandlocationsetaeofano- adanalplates, butdiffers fromthelatterbythepresenceofposteriorfurrowsonprodorsum (versus absentin A. ethiopicus), erect, shorterrostralsetae (versuslongerandprocum- bent), vestigiallamellarsetae (versusminutelamellarsetae), lengthofsetae h ofsubcapitulumlonger (versusshorterthandistancebetweenthem), ar- rangementofgenitalsetae: 4+2: 3 (versus 4+1: 4) andlocationsetae d and l” of femora I more posteriorly in A. ethiopicus.

Thenewspeciesisalsosimilarto Arphthicarusindiligens ( Niedbała, 1984) fromMalawibytheshapeandlengthofprodorsalsigillaryfields, theshapeof sensilli, erectandwidelydistancedrostralsetae, posteriorfurrowsofprodor- sumpresent, presenceoffourpairsofnotogastrallyrifissures, arrangementof analandadanalsetae, butdiffersfromthelatterbyshorterinterlamellar, ros- tralandnotogastralsetae (versuslonger A. indiligens), lamellarsetaevestigial (versusnotvestigial), absenceoflateralcarinaeontheprodorsum (versus carinaepresent), setae c 2 distantfromanteriormargin (versusnearmargin), andgenitalsetae g 6 arelocatedslightlybelowof g 5 (versussetae g 6 arelocated slightlybelowsetae g 3).