Niambia botswanaensis Cardoso, Taiti & Ferreira, 2021

Cardoso 1, Giovanna Monticelli, Preez 2, Gerhard Du, Taiti 3,4, Stefano & Ferreira 1,5, Rodrigo L., 2021, New troglobitic species of Niambia from Botswana and Namibia (Crustacea, Isopoda, Oniscidea), Subterranean Biology 40, pp. 91-108 : 91

publication ID	https://dx.doi.org/10.3897/subtbiol.40.72499
persistent identifier	https://treatment.plazi.org/id/2DFFD850-13FE-5023-B1D3-01E6594467E9
treatment provided by	Subterranean Biology by Pensoft
scientific name	Niambia botswanaensis Cardoso, Taiti & Ferreira
status	sp. nov.

Treatment

Niambia botswanaensis Cardoso, Taiti & Ferreira sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Niambia sp. 1; Javidkar et al. 2015: 575, figs 2, 3.

Material examined.

Holotype. • Male ; Botswana, North-western District , Gcwihaba region, Diviner’s Cave, 20°08'32.2"S, 21°12'36.6"E, 11 January 2016, leg. G. Du Preez (IG12112513lag) (ISLA 78790) GoogleMaps . Paratypes. • 1 male, 4 females, same data as holotype (IG12112513lag) ( ISLA 78791) GoogleMaps ; 2 males, 2 females, same locality and date (IG12030901-5) ( ISLA 78792) GoogleMaps ; 2 males, 1 female, same locality, 20 October 2011 ( Parod root) ( ISLA 78793) GoogleMaps ; 4 males, 5 females, same locality and date ( ISLA 78794) GoogleMaps ; 2 males, 6 females, same locality and date, leg. G. Du Preez ( MZUF 9901) ( IG120309 View Materials A-12) GoogleMaps .

Description.

Maximum length: male, 3 mm; female, 3.5 mm. Colorless (Fig. 1A View Figure 1 ). Dorsal surface of pereon sparsely granulated with scattered triangular scale-setae (Fig. 1E, F View Figure 1 ); one line of noduli laterales per side on pereonites, close to posterior margins and at certain distance from lateral margins, b/c and d/c co-ordinates as in Fig. 2A View Figure 2 ; gland pores not visible. Cephalon (Fig. 1B View Figure 1 ) with suprantennal line visible only at sides, no frontal line, eyes absent. Pleon slightly narrower than pereon, pleonites 3-5 with falciform epimera. Telson (Fig. 2B View Figure 2 ) triangular with straight sides, obtuse apex. Antennula (Fig. 2C View Figure 2 ) with three articles, second article shortest, distal article with eight short aesthetascs. Antenna (Figs 1B-D View Figure 1 , 2B View Figure 2 ) reaching distal margin of pereonite 3 when extended backward; fifth article of peduncle and flagellum subequal in length; flagellum with two articles, second article about 3 times as long as first. Mandibles (Fig. 2E, F View Figure 2 ) with molar penicil consisting of 5-6 setae arising from common stem; left mandible with 2 + 1 penicils, right mandible with 1+1 penicils. Maxillula (Fig. 2G View Figure 2 ) outer branch with 4 + 5 teeth (three of them slightly cleft) plus one small tooth between outer and inner teeth; inner branch with two short penicils. Maxilla (Fig. 2H View Figure 2 ) with bilobate apex, inner lobe distinctly smaller than outer lobe. Maxilliped (Fig. 2I View Figure 2 ) basis rectangular; palp basal article with two stout setae; endite rectangular, medial portion with one long seta, distal margin with one tooth. Pereopod dactylus with inner claw stout, slightly longer than outer one; pereopod 1 (Fig. 3A View Figure 3 ) carpus with transversal grooming brush. Pleopod exopods without visible respiratory structures. Uropod (Fig. 2B View Figure 2 ) protopod reaching distal margin of telson, slightly grooved on outer margin; endopod and exopod inserted at same level, endopod distinctly shorter than exopod.

Male. Pereopods with sternal margin bearing some apically trifid setae; pereopod 7 (Fig. 3B View Figure 3 ) with no distinct sexual modifications. Pleopod 1 (Fig. 3C View Figure 3 ) exopod round; endopod longer than exopod, distal portion tapering. Pleopod 2 (Fig. 3D View Figure 3 ) exopod triangular, bearing one subapical seta, outer margin concave; endopod longer than exopod. Pleopod 3-5 exopods as in Fig. 3E-G View Figure 3 .

Etymology.

The new species is named after Botswana, where the specimens were collected.

Taxonomic remarks.

This and the following new species are included in the genus Niambia since they show all the characters of the genus, except for lacking respiratory areas in the pleopod exopods. This condition may be due to a secondary reduction due to the humid environment of the caves where they occur. Most of the species of Niambia are epigean and inhabit semi-arid habitats in South West Africa ( Barnard 1932).

In lacking the frontal line on cephalon, N. botswanaensis sp. nov. resembles N. duffeyi Ferrara & Taiti, 1981 and N. longiantennata Taiti & Ferrara, 1991 from Ascension Island, as well as N. septentrionalis Taiti & Ferrara, 2004 from Socotra Island (Yemen). However, it is distinct in lacking pigmentation and eyes, and in the shape of the male pleopod 1 exopod without posterior point (compare fig. 11 in Ferrara and Taiti 1981; fig. 30 in Taiti and Ferrara 1991; and fig. 33D in Taiti and Ferrara 2004).

Some specimens of this species from the type locality were sent to Dr. M. Javidkar in Adelaide for molecular analysis and were included in a phylogenetic cladogram as Niambia sp. 1 ( Javidkar et al. 2015).

Ecological remarks.

The Koanaka and Gcwihaba hills are located in the North-West District (or Ngamiland) of Botswana. The lithology was described by Williams et al. (2012) as Precambrian dolomites from the Damara Sequence. According to Thies and Lewis (2015) the surrounding environment (known as the Kalahari Thirstland) is semi-arid with shrub savanna vegetation and forms part of the Savanna Biome. Annual precipitation typically ranges between 400 and 500 mm and temperatures from -8.5 °C to 42.2 °C.

The Koanaka and Gcwihaba hills collectively host four known caves with natural entrances, which include Gcwihaba Cave, a local tourist attraction formerly known as Drotsky’s Caverns (Fig. 4A View Figure 4 ). Furthermore, using gravimetric surveys and exploration drilling, an additional five caves were discovered, opened and explored ( Harvey and Du Preez 2014; Du Preez et al. 2015). One of these is Diviner’s Cave, the type locality of Niambia botswanaensis sp. nov. Initial exploration of Diviner’s Cave commenced in 2011 after a 700 mm diameter vertical shaft (borehole) was drilled (Fig. 4B-E View Figure 4 ). This shaft is 41 m deep and enters the cave in a chamber called 'Entrance Alcove’ (Fig. 4C, D View Figure 4 ). Upon initial exploration of the cave, high CO2 levels were encountered, especially in areas lower than the general cave development level. However, since the cave was allowed to vent following the drilling of the borehole, CO2 levels gradually decreased and facilitated further exploration. As can be expected, atmospheric conditions in Diviner’s Cave and those with man-made entrances were quite distinct from the observed in local caves with natural entrances ( Du Preez et al. 2015). All the caves associated with the Koanaka and Gcwihaba hills are protected and declared as Botswana National Monuments.

Specimens of Niambia botswanaensis sp. nov. were collected by hand in Calcite Baboon Chamber, Diniver’s Cave. The collection site is located (Fig. 4F, G View Figure 4 ) at the one end of this chamber where large Ficus cordata roots penetrate the cavity ( Du Preez et al. 2015). Associated with this root system is a community of soil invertebrates that include pseudoscorpions ( Botswanoncus ellisi Harvey & Du Preez, 2014), diplurans ( Japygidae ), centipedes ( Cryptops sp.) and termites.

During sampling atmospheric conditions were measured using a Fluke 971 Temperature Humidity Meter. An average temperature of 28.5 ± 0.5 °C and relative humidity of 93 ± 5.4% were recorded in Diviner’s Cave.