Zoosyst. Evol. 96 (2) 2020, 769-779 | DOI 10.3897/zse.96.56885 yee BERLIN Feaella (Tetrafeaella) obscura sp. nov. — a new pseudoscorpion species from the Maldives (Arachnida, Pseudoscorpiones), and an updated identification key to the subgenus Feaella (Tetrafeaella) Janos Novak!, Michelle Lorenz’, Danilo Harms? 1 Hungarian Natural History Museum, Department of Zoology, Baross u. 13, H-1088 Budapest, Hungary 2 Zoological Museum, Center of Natural History, Universitat Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany http://zoobank.org/4D35899 1-0404-4F F9-A9BD-0E9288BSE355 Corresponding author: Janos Novak (novakjanosOl@gmail.com) Academic editor: Pavel Stoev # Received 27 July 2020 # Accepted 8 September 2020 # Published 19 November 2020 Abstract The Feaellidae Ellingsen, 1906 is a small but ancient family of pseudoscorpions with 20 extant species across the Southern Hemi- sphere, and fossils from the Lower Cretaceous of Myanmar and the Eocoene of Europe. Here, we describe and illustrate Feaella (Tetrafeaella) obscura sp. nov. as a new species from the Maldives archipelago in the Indian Ocean. This is the first record of Feaella from a young oceanic island and may indicate a potential for long-distance dispersal in this lineage. We also elevate Feaella (T.) capensis nana Beier, 1966 to full species rank as F. (7.) nana Beier, 1966 and provide an identification key to the members of the subgenus Feaella (Tetrafeaella), thereby facilitating the identification of species. Key Words biogeography, dispersal, endemism, false scorpion, taxonomy Introduction Pseudoscorpions belonging to the family Feaellidae Ellingsen, 1906 are amongst the most unusual arachnids and have a spectacular morphology that includes a carapace with multiple frontal lobes, a dorsoventrally flattened and heavily sclerotised body, and pedipalps that are stout, heavi- ly armed and without a venom gland tn both fingers (Harvey et al. 2016b; Judson 2017). The family has a Pangaean distribution and amber fossils are known from the Lower Cretaceous of Myanmar (Henderickx and Boone 2016) and Baltic amber in Europe (Hendrickx and Boone 2014; Harms and Dunlop 2017), whereas twenty extant species are found in tropical and subtropical regions in central and southern Africa, north-western Australia, tropical India and Sri Lanka, the Seychelles, Madagascar, and Brazil (Fig. 1) (Harvey 2013, 2018; Harvey et al. 2016a, b; Judson 2017). Their strange morphology aside, feaellids are also of fundamental importance in understanding the evolution of character systems in pseudoscorpions (Benavides et al. 2019). According to the most recent transcriptomic analysis (Benavides et al. 2019), Feaellidae and its sis- ter-family Pseudogarypidae Chamberlin, 1923 are the sister group to all pseudoscorpions with venom glands in the pedipalp fingers and placed within their own sub- order Atoposphyronida Harvey, 2019. The present-day distribution of the family and the fossil record (Harms and Dunlop 2017) suggests that this is a remnant lineage that may have survived in relictual habitats across the Southern Hemisphere. Feaellidae are grouped into two _ subfamilies, Feaellinae (Ellingsen, 1906) and Cybellinae Judson, 2017 (Judson, 2017). Feaellinae comprises two genera, Feaella Ellingsen, 1906 from Africa, India, Madagas- Copyright Janos Novak etal. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. rar ae Janos Novak et al.: A new Feaella (Tetrafeaella) pseudoscorpion species from the Maldives ®: Recent records @: Fossil records ®@ : Feaella (T.) obscura sp. nov. Figure 1. Known distribution of the family Feaellidae. Circle colours: blue = Recent records; green = fossil records; and red = F: (7) obscura sp. nov. car, the Seychelles, Sri Lanka and Australia (Harvey 2013); and Jporangella Harvey, 2016 from South Amer- ica (Harvey et al. 2016b). Depending on the number of frontal lobes, Feael/a is presently divided into three subgenera: Feaella (Feaella, six processes), Feaella (Difeaella, two processes), and Feaella (Tetrafeaella, four processes) (Mahnert 1982). Most species are nar- row-range endemics that are only known from a single or few localities, have poor dispersal capacities, and are restricted to specific habitats such as rocky outcrops (Harvey et al. 2016a), near or in caves (Batuwita and Benjamin 2014, Judson 2017; Harvey 2018), or rainfor- est habitats (Harvey et al. 2016b). In Africa and South America, these animals have been collected from leaf litter (Mahnert 1982; Harvey et al. 2016a, b) but in mainland Australia they have been found under rocks (Harvey et al. 2016a), although Harvey (1989) also recorded Feaella anderseni from vine thicket litter. In eastern Asia the only known records are from within caves (Judson 2017; Harvey 2018). In this paper, we are describing Feaella (Tetrafeaella) obscura sp. nov. from the Maldives, which are comprised predominantly of young reef-islands and atolls in the In- dian Ocean (Kench et al. 2005). The description is based on old museum specimens rather than recently collected material but our species does not match any of the de- scribed species and documents the first possible case of oceanic dispersal in this lineage. To diagnose this species accurately and assist the identification of Feaella species across the world, we also provide a key to the species of Feaella (Tetrafeaella). Finally, we also discuss the taxo- nomic status of Feaella (Tetrafeaella) capensis nana Bei- er, 1966 from southern Africa and elevate this population to species rank. zse.pensoft.net Material and methods The specimens were found during an inventory in the collections of the Hungarian Natural History Museum (HNHM) and stored in 70% ethanol. They were cleared in a 3:1 mixture of lactic acid and gelatine to be examined with a Zeiss Stemi 2000-c stereomicroscope and a Zeiss Axioskop 2 light compound microscope. Drawings and measurements were made with the aid of the Zeiss Ax- ioskop 2 microscope. Measurements were taken using the Olympus Soft Imaging analySIS work 5.0 software. Dig- ital images were taken with a custom-made BK Plus Lab System by Dun, Inc. with integrated Canon EOS 7D Mark II, microscopic lens (5x and 10x magnification) and the Zerene stacker version 1.04 software. Scanned electron 1m- ages were taken from temporarily dried specimens mount- ed on copper wire, using a Hitachi TM4000 Plus scanning electron micrograph (SEM). Mensuration follows the ref- erence points in Chamberlin (1931) as does the terminol- ogy, except for modifications for the pedipalps and chelal trichobothria (Harvey 1992), the chelicera (Judson 2007), and the faces of the appendages (Harvey et al. 2012). Abbreviations Cheliceral trichobothriotaxy: bs = basal seta; sbs = sub- basal seta; is = interior seta; es = exerior seta; /s = lam- inal seta; gs = galeal seta. Chelal trichobothriotaxy: eb = externo-basal; esb = externo-subbasal; est = exter- no-subterminal; et = externo-terminal; ib = interno-basal; isb = interno-subbasal; ist = interno-subterminal; it = in- terno-terminal; t = terminal; st = subterminal; sb = sub- basal; b = basal; dt = duplex trichobothrium. Zoosyst. Evol. 96 (2) 2020, 769-779 Results Taxonomy Superfamily Feaelloidae Ellingsen, 1906 Family Feaellidae Ellingsen, 1906 Subfamily Feaellinae Ellingsen, 1906 Remarks. The genus Feae//a is divided into three subge- nera: Feaella (Feaella), Feaella (Difeaella), and Feaella (Tetrafeaella) based on the number of frontal lobes on the carapace (Mahnert 1982). Our new species has four lobes and is assigned to Tetrafeaella, hence the diagnosis is against similar species with four protuberances. The species can also be diagnosed against the east Asian ge- nus Cybella Judson, 2017 which lacks pleural sclerites on the abdomen which are obvious tn our species. Feaella (Tetrafeaella) obscura sp. nov. http://zoobank.org/C6FF5DD9-BE35-4A EA-A049-3BB24048D9DB Figs 2A-F, 3A-H, 4A-F, 5A-G Type material. Holotype female from the Maldives, Kabudu Island (might refer to Kaudu [0°17'N, 73°1'E] or Kandudu Islands [2°19'N, 72°55'E]), June 1984, leg: Gy6z6 Horvath. [On the label: Maldives, Kabudu sz., 1984. VII. leg.: Gy6z6 Horvath] (HNHM Pseud-2009). Paratypes: 1 male (HNHM Pseud-2010) and 1 female (ZMH-A0003101); all same data as holotype. Etymology. The name of the species refers to the ob- scure evolutionary and geographic origins of the species that is unlikely to have evolved on the young island that is the locus typicus. Distribution. Maldive Islands (Fig. 1). Diagnosis. A typical Feaella (Tetrafeaella) habitus (Figs 2A, B, 3A) that differs from all the other species of the subgenus by the following combination of charac- ters: with the anteromedian lobes of carapace being closer to each other than to the anterolateral ones; anterolateral pair approximately as broad as anteromedian pair, anter- omedian lobes longer. Palpal trochanter with prolateral triangular protuberance, femur very robust (1.70—1.76x) with two pronounced triangular process on prolateral cor- ner near base. Chelae are approximately as long as the palpal femora. Chelae with dorsal protuberance at basal third of finger, and a large medial tooth at the base of each fingers. Chelal trichobothriotaxy: esb and est situated on basal third of retrolateral face; ib, isb and ist situated ba- sally; eb and it situated subdistally; dt situated distally; esb midway between est and isb; ist equidistant from est and esb; isb is closer to ib than to ist, on the movable chelal finger ¢ and sb are situated midway between b and st. Pedal coxa I with medioposterior depression (coxal pit), a single primary coxal spine posteriorly; coxa II with 9 secondary spines in males and 8—11 in females. Pleural membrane with a dorsal row of 15 and a ventral row of 14 sclerotised pleural platelets. See detailed differentiation from the most similar species in the Differential diagno- 77 sis, and differentiation from all the other species of the subgenus in the key. Description. (Holotype female, paratype male and female). Colour and cuticular surface (in alcohol). scle- rotised parts reddish-brown, with reticulated cerotegu- ment (Fig. 2A—F). Setae: most vestitural setae short, slightly curved, in- conspicuous and acuminate. Chelicera (Fig. 5A): hand with five setae, is and /s ad- jacent to each other, movable finger with subdistal seta. Galea thick, without rami. Fingers without teeth. Serrula exterior with ca. 16 blades, lamina exterior absent. Ral- lum absent. Pedipalps (Figs 2F, 5B): trochanter with prolater- al triangular protuberance, femur very robust with two pronounced triangular process on prolateral corner near base, 0.63—0.69/0.37—0.40 (1.70-1.73x) in females and 0.51/0.29 (1.76x) in male; patella conical, and with two lyrifissures at base, 0.51-0.54/0.18-0.19 (2.83-2.84x) in females and 0.41/0.14 (2.93x) in male; chela tubular (Figs 3G, 4A—-F, 5C), chela (with pedicel) 0.60—0.61 in females and 0.53 in male, chela (without pedicel) 0.57 in females and 0.50 in male; hand without pedicel and longer than broad. Fixed chelal finger and hand with eight major trichobothria, plus duplex trichobothrium (dt), movable chelal finger with four trichobothria: esb and est situated on basal third of retrolateral face; 1b, isb and ist situated basally; eb and it situated subdistally; dt situated distal- ly; esb midway between est and isb; ist equidistant from est and esb; isb is closer to ib than to ist. On the mova- ble chelal finger ¢ and sb are situated midway between b and st (Fig. 5C). Venom apparatus absent. Chelal hand very small; retrolateral condyle rounded; with dorsal pro- tuberance at basal third of finger (Fig. SC). Chelal teeth large, retrorse and diastemodentate: fixed finger with two parallel marginal dental line, one with 11 and one with 9 teeth, 9 prolateral and 7 distal teeth in male; 12—13 and 9-13 marginal, 9-10 prolateral and 34 distal teeth in fe- males; movable finger with two parallel marginal dental line with 9 + 9 , 9 prolateral and 7 distal teeth in male; 12 and 9 marginal, 9-10 prolateral and 6 distal teeth in fe- males; plus a large medial tooth at the base of each finger. Movable chelal finger with several specialised, lanceolate setae midway between ¢ and tip of finger; located in a depression (Fig. 3H). Carapace: anterior margin with four lobes, the an- teromedian lobes are closer to each other than to the anterolateral ones; anterolateral pair approximately as broad as anteromedian pair, anteromedian lobes longer (Figs 2D, 3E). Four lobes between eyes. Lateral margins of carapace nearly parallel, slightly widened medially; carapace in females 1.27—1.28x, in male 1.24 longer than broad; with two pairs of eyes situated on tubercles away from anterior carapace margin; all eyes with tape- tum; with numerous inconspicuous setae; with a pair of postero-lateral processes; shallow anterior and posterior furrows present. Three slit-like lyrifissures at the level of posterior one-fourth of carapace on each side, and two near posterior base. zse.pensoft.net 772 Janos Novak et al.: A new Feaella (Tetrafeaella) pseudoscorpion species from the Maldives 1mm Of mn O5mm Figure 2. Feaella (Tetrafeaella) obscura sp. nov, female holotype (HNHM Pseud-2009). A. Body, dorsal view; B. Body, ventral view; C. Body, lateral view; D. Carapace, dorsal view; E. Coxal region; F. Left pedipalp, dorsal view. Coxal region (Figs 2E, 3B): pedipalpal coxa with strong basal lateral processes; with numerous small setae and 3 acuminate apical setae. Coxa I with medioposterior depression (coxal pit), a single primary coxal spine pos- teriorly; coxa II with 9 secondary spines in male and 8-11 in females (Fig. 3C). Pedipalpal coxa somewhat longer as combined length of leg coxae I-IV. Legs (Fig. 5D, E): claws simple, arolium shorter than claws. Metatarsi and tarsi fused. Each patella with a shal- low dorsal depression. Tarsi without tactile setae, vestitu- ral setae short and acuminate. Patellae I and II slightly shorter than femora I and II; patellae III and IV nearly twice as long as femora ITI and IV. Abdomen: \onger than broad, somewhat ovoid; tergites HI—-IX and sternites [V—X with distinct median suture lines; tergite XI and sternite XI fused; tergite XII and sternite XII (anal sclerites) strongly scle- zse.pensoft.net rotised; most segments with numerous setae; tergite XII and sternite XII with two setae; anal region with raised circular rim (Fig. 3D). Setae of sternites IT and III longer than vestitural setae. Pleural membrane with a dorsal row of 15 and a ventral row of 14 sclerotised pleural platelets. Genital region: Female (Figs 3F, 5F): 10 acuminate microsetae on each plate. Male (Fig. 5G): 40-45 acumi- nate microsetae on genital plate. Inner genital structures could not be clearly seen. Measurements (in mm, ratios in parentheses): Male paratype. Body 1.83. Carapace 0.51/0.41 (1.24x). Chelicera 0.19/0.10 (1.9x), movable finger 0.085. Palpal femur 0.51/0.29 (1.76x), patella 0.41/0.14 (2.93x), chela (with pedicel) 0.53/0.13 (4.08), chela (without pedicel) 0.50, hand (with pedicel) 0.15, hand (without pedicel) 0.12, movable finger 0.37. Leg I. trochanter 0.12/0.19 Zoosyst. Evol. 96 (2) 2020, 769-779 TLS A OOPX-7] WWI OL AXSL wnooz Ho a a * -! E = a, “A a > a4 Ts) = iia . ahs 15kV 12.4mm L-x400 15kV 10.4mm L-x1.00k 15kV 12.8mm L-x2.00k | ‘Oum J 15kV 10.5mm L-x4.00k 20.0um Figure 3. Feaella (Tetrafeaella) obscura sp. nov, female holotype (HNHM Pseud-2009): SEM images. A. Body, dorsal view; B. Coxal region; C. Coxae I and II with medioposterior depression and coxal spines (primary coxal spines of coxae I highlighted in purple); D. Anal region; E. Carapace, dorsal view; F. Female genital region with pedal coxae IV; G. Right chelal tip, dorsal view; H. Specialised, lanceolate setae (marked with arrow) midway between ¢ and finger tip. (0.62x), femur 0.21/0.06 (3.50x), patella 0.18/0.07 Females (holotype, followed by paratype in parentheses (2.57), tibia 0.17/0.06 (2.83%), tarsus 0.23/0.05 (4.60x). and then the ratios also in parentheses). Body 2.16 (2.46). Leg IV. trochanter 0.22/0.12 (1.83x), femur 0.16/0.08 | Carapace 0.61/0.48 (0.64/0.50) (1.27—1.28%x). Chelicera (2.00x), patella 0.28/0.10 (2.80%), tibia 0.32/0.06 (5.33x), — 0.20/0.12 (0.21/0.12) (1.67—1.75x), movable finger 0.095 tarsus 0.32/0.05 (6.4%). (0.10). Palpal femur 0.63/0.37 (0.69/0.40) (1.70—1.73%), zse.pensoft.net 774 15kV 11.3mm L-x500 200um 15kV 10.5mm L-x500 15kV 15.3mm L-x600 200m 15kV 16.0mm L-x600 Janos Novak et al.: A new Feaella (Tetrafeaella) pseudoscorpion species from the Maldives 15kV 12.8mm L-x600 200”um 200um 15kV 14.7mm L-x600 Figure 4. Feaella (Tetrafeaella) obscura sp. nov, female holotype (HNHM Pseud-2009): SEM images. A. Left chela, retrolateral view; B. Left chela, dorsomedial view; C. Left chela, ventral view. Male paratype (HNHM Pseud-2010): SEM images. D. Left chela, retrolateral view; E. Left chela, ventral view; F. Left chela, medial view. patella 0.51/0.18 (0.54/0.19) (2.83—-2.84x), chela (with pedicel) 0.60/0.16 (0.61/0.16) (3.75—3.81 x), chela (without pedicel) 0.57 (0.57), hand (with pedicel) 0.16 (0.17), hand (without pedicel) 0.12 (0.10), movable finger 0.40 (0.41). Leg I. trochanter 0.15/0.11 (0.16/0.12) (1.33-1.36x), fe- mur 0.24/0.07 (0.27/0.08) (3.38-3.43x), patella 0.22/0.08 (0.21/0.09) (2.33-2.75x), tibia 0.20/0.07 (0.22/0.07) (2.85-3.14x), tarsus 0.22/0.05 (0.22/0.05) (4.4x). Leg IV. trochanter 0.26/0.14 (0.27/14) (1.86—1.93%x), fe- zse.pensoft.net mur 0.18/0.10 (0.19/10) (1.8-1.9x), patella 0.36/0.11 (0.37/0.12) (3.08-3.27x), tibia 0.42/0.06 (0.44/0.07) (6.29-7.00x), tarsus 0.36/0.05 (0.38/0.06) (6.33—7.20x). Differential diagnosis. Aside from Feaella (T.) obscu- ra there are twelve species of Feaella (Tetrafeaella): F: (1) affinis Hirst, 1911 (Seychelles); F? (7) capensis Bei- er, 1955, F: (7’) mucronata Tullgren, 1907 and F: (7°) par- va Beier, 1947 (all South Africa), F’ (7°) indica Chamber- lin, 1931 (India and Sri Lanka), F (7-) /eleupi Beier, 1959 Zoosyst. Evol. 96 (2) 2020, 769-779 FID : > ‘s 3 ee X Lin. toate, To ee Oa ZR ais ‘ ae ee Se ee ee = ae % Sak A ee ze ‘ ® & ee eee x oe m ae ax GRE 4 a Onn FES : IB EOE OL EGOM, & % PS e IOS RRO SOROS OIF OR" = Wh We ASE ples ster ems cca Ge ioe Se (e] ff rE oO @ Oo ie 6) a