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The first troglobitic Pseudochthonius Balzan, 1892
(Pseudoscorpiones, Chthoniidae) from the karst area
of Serra do Ramalho, Brazil: a threatened species
Leonardo de Assis1, Diego Monteiro von Schimonsky1, Maria Elina Bichuette1
1Laboratório de Estudos Subterrâneos, Departamento de Ecologia e Biologia Evolutiva, Universidade Federal
de São Carlos, Rodovia Washington Luís, km 235, PO Box 676, CEP 13565-905, São Carlos, São Paulo,
Brazil
Corresponding author: Diego Monteiro von Schimonsky (dmvschimonsky@gmail.com)
Academic editor: Martina Pavlek|Received 4 November 2021|Accepted 8 November 2021|Published 23 November 2021
http://zoobank.org/3209150E-9866-42B1-A8AA-42C5B67A9FEF
Citation: Assis LD, Schimonsky DMV, Bichuette ME (2021) e rst troglobitic Pseudochthonius Balzan, 1892
(Pseudoscorpiones, Chthoniidae) from the karst area of Serra do Ramalho, Brazil: a threatened species. Subterranean
Biology 40: 109–128. https://doi.org/10.3897/subtbiol.40.77451
Abstract
Pseudochthonius ramalho sp. nov. is described to Gruna do Vandercir cave, in the Serra do Ramalho karst area,
southwestern Bahia, Brazil. is area has an extensive limestone outcrop, with several caves, and the occurrence
of potential minerals that are nancially attractive for mining projects. e new species shows troglomorphic
characteristics such as the depigmentation of the carapace and absence or reduction of eyes. It is a rare troglo-
bitic species, and following the criteria of IUCN, we categorized the species as Critically Endangered – CR,
IUCN criteria B1ab(iii)+2ab(iii). According to Brazilian legislation, locations, where critically endangered spe-
cies live, can be protected by law, and we consider this cave/region to be of maximal relevance for protection.
Keywords
Arachnida, Bahia State, Chthoniinae, conservation, endemic, troglobite
Introduction
Pseudoscorpions are represented in the Brazilian fauna by 14 families and 176 species (Har-
vey 2013; Schimonsky and Bichuette 2019a; Benavides et al. 2019; Viana and Ferreira
Subterranean Biology 40: 109–128 (2021)
doi: 10.3897/subtbiol.40.77451
https://subtbiol.pensoft.net
Copyright Leonardo de Assis et al. 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.
RESEARCH ARTICLE
Subterranean
Biology Published by
The International Society
for Subterranean Biology
A peer-reviewed open-access journal
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
110
2020; Bedoya-Roqueme et al. 2021). Only 33 species are known to occur in subterranean
habitats (caves) belonging to 12 genera and eight families (Beier 1969; Mahnert 2001; An-
drade and Mahnert 2003; Ratton et al. 2012; Schimonsky et al. 2014; Viana et al. 2018;
Schimonsky and Bichuette 2019b; Viana and Ferreira 2020; Bedoya-Roqueme et al. 2021).
e family Chthoniidae includes three subfamilies, Chthoniinae, Tridenchthoniinae, and
Lechtyiinae, currently with 50 genera and 769 described species in the world (Harvey 2013;
Zhang and Zhang 2014; Gao et al. 2018; Zaragoza and Reboleira 2018; Benavides et al.
2019). It occurs in several regions of the world, with the greatest diversity in the USA (147),
Italy (84), Spain (59), Australia (36) (Harvey 2013). In Brazil, the family Chthoniidae has
29 species in eleven genera, Heterolophus Tömösváry, 1884, Tridenchthonius Balzan, 1887,
Lechthyia Balzan, 1892, Pseudochthonius Balzan, 1892, Compsaditha Chamberlin, 1929,
Tyrannochthonius Chamberlin, 1929, Austrochthonius Chamberlin, 1929, Soroditha Cham-
berlin & Chamberlin, 1945, Neoditha Feio, 1945, Cryptoditha Chamberlin & Chamber-
lin, 1945 and Lagynochthonius Beier, 1951 (Harvey 2013; Lira et al. 2020).
e genus Pseudochthonius is characterized by the absence of an intercoxal tuber-
cle, the presence of coxal spines on coxae I and II, and in most cases, having strongly
sigmoid palpal chelal ngers (Muchmore 1986; Mahnert and Adis 2002). Pseudochtho-
nius is known from Asia (one species from Saudi Arabia), Africa (ve species distrib-
uted in the Republic of Congo and Ivory Coast), Central America [six living species
of which two are troglobites: P. troglobius Muchmore, 1986 from Mexico (Muchmore
1986) and P. arubensis Wagenaar-Hummelinck, 1948, from the Netherlands Antilles
(Wagenaar-Hummelinck1948) and one fossil species (Schawaller 1980)] and South
America, with nine species in Brazil (Harvey 2013; Mahnert et al. 2014; Lira et al.
2020), followed by Ecuador with three, Venezuela with two and Uruguay with one
species (Harvey 2013). In Brazil, two Pseudochthonius species are troglobites (Mahnert
2001), i.e., they have exclusive populations in the hypogean environment: P. strinatii
Beier, 1969 and P. biseriatus Mahnert, 2001. Pseudochthonius is one of the four Chtho-
niidae genera that occurs in Brazilian caves, previously reported only for13 caves, with
four species (Beier 1969; Mahnert 2001). Recently, this genus was recorded in other
karst areas and biogeographical provinces, increasing its distribution to 37 caves (Schi-
monsky and Bichuette 2019b).
Here, we describe a new Pseudochthonius species found in a single cave in the Serra
do Ramalho karst area, southwestern Bahia, Brazil. We also provide data regarding the
conservation status of the species and the area.
Material and methods
Study area
e karst area of the Serra do Ramalho region (Fig. 1), southwestern Bahia, Brazil,
is composed of rocks containing rare metals with mining potential (Silva Junior and
Campos 2016). e region is formed by extensive limestone areas with many caves
New troglobitic Pseudochthonius from Serra do Ramalho 111
and karst system formations (Fig. 2), sheltering a high diversity (e.g., Bichuette and
Trajano 2004, 2005; Bichuette and Rizzato 2012; Gallão and Bichuette 2018). It
belongs to the Jacaré formation, Bambuí group, composed of dark, heterogeneous
limestones, presenting intercalations with layers of claystone, deposited about 750
to 600 million years ago (Rubbioli et al. 2019). e region located in the middle of
the São Francisco River basin is characterized by a tropical dry climate, with a dry
winter and an average annual precipitation rate between 800 and 1000 mm (Gon-
çalves et al. 2018).
Material examined and treatment of specimens
Specimens were prepared by immersion in 85% lactic acid at room temperature for
two weeks (Judson 1992). ey were then examined by preparing temporary slide
mounts with 10 mm coverslips supported by sections of nylon sh line (Harvey 2021).
Specimens were examined with Nikon SMZ660 Stereomicroscope and Leica DMLS
compound microscope and the male holotype was illustrated with the aid of a cam-
era lucida. e female specimen was examined and illustrated through a Scanning
Electron Microscope (SEM, FEI Quanta 250) in low-vacuum mode (ESEM) located
at the “Instituto Nacional de Ciência e Tecnologia dos Hymenoptera Parasitoides da
Região Sudeste Brasileira”. After the study, the male specimen was cleaned in water and
returned to 70% ethanol with its dissected parts in glass vials, and the female specimen
was stored dry, due to the SEM picturing process.
Images (Figs 4, 10) were taken with a Leica DFC 295 camera attached to a Leica
M205C stereomicroscope with a Planapo 1.0× objective. Figures were produced from
stacks of images on Leica Application Suite (LAS) software v3.7. e drawings were
Figure 1. Map depicting the known distribution of Pseudochthonius ramalho sp. nov. in Gruna do Van-
dercir cave, located in Bahia state. e cave belongs to karst area in Jacaré formation, Bambuí group.
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
112
digitized and vectorized on Illustrator CC 2019. e maps were produced with the
software QuantumGis Desktop 3.6.0 (QGis Open Source Geospatial Foundation).
e coordinates were obtained from eld trips to the study location with a global po-
sitioning system (GPSGarmin 60CSx).
e examined specimens are deposited in Laboratório de Estudos Subterrâneos, in
Universidade Federal de São Carlos (LES, curator: Maria Elina Bichuette). For com-
parative purpose of some morphological characters like classical troglomorphisms in
pseudoscorpions (eyes/ocular structures, proportionally longer body, and ratio pedi-
palpal chela/carapace), the new species was compared to two hypogean species, and
one undetermined epigean species of Pseudochthonius sp.
Comparative material. B – Parana Forest Province • Pseudochthonius stri-
natii;1♂, São Paulo, Iporanga, Parque Estadual Turístico do Alto Ribeira, Sumidouro
da Passoca cave; 24°33'57"S, 48°43'W; 03.xii.2013; Bichuette ME, Gallão JE, Fer-
nandes CS, Rizzato PP, Fonseca R and Arnone I leg.; LES9391. – Parana Forest Prov-
ince • Pseudochthonius biseriatus; 1♂Minas Gerais, Itacarambi, Olhos d‘Água cave;
15°7'0.10"S, 44°10'0.10"W; 24.vii.2012; Bichuette ME, Gallão JE, and Rizzato PP
leg.; LES9434. – Caatinga Province • Pseudochthonius sp. undetermined species; 1♂;
Bahia, Carinhanha, epigean habitat near Viração cave; 26.vii.2012; LES9629.
Terminology and mensuration
e terminology and measurements mostly follow Chamberlin (1931). Legs, pedi-
palps, and trichobothria terminology follows Harvey (1992) except for the chelal mov-
able nger, which follows Mahnert et al. 2014. For chelicera Judson (2007), chaetotac-
tic formulae of chelicera follow Gabbutt and Vachon (1963) and the duplex trichobo-
thria follow Judson (2018).
Figure 2. A Gruna do Vandercir cave B surroundings of Gruna do Vandercir cave with its dry character-
istic vegetation (Images A Adriano Gambarini B Maria Elina Bichuette).
New troglobitic Pseudochthonius from Serra do Ramalho 113
Abbreviations
♂ male; ♀ female.
chelal trichobothria:
b basal;
sb sub–basal;
st sub–terminal;
t terminal;
ib interior basal;
isb interior sub–basal;
ist interior sub–terminal;
it interior terminal;
eb exterior basal;
esb exterior sub–basal;
est exterior sub–terminal;
et exterior terminal;
dx duplicate trichobothria.
cheliceral setae:
gl galeal;
dt dorsal terminal;
dst dorsal sub–terminal;
db dorsal basal;
vt ventral terminal;
vb ventral basal;
di isolated subapical
tooth.
e following body structures were measured and compared proportionally for the
characterization of possible troglomorphisms: carapace; chelal hand; chelal xed nger
(Christiansen 2012; Harvey and Wynne 2014; Feng et al. 2020; Harvey and Cullen 2020).
Results
Taxonomy
Family Chthoniidae Daday, 1889
Subfamily Chthoniinae Daday, 1889
Tribe Chthoniini Daday, 1889
Genus Pseudochthonius Balzan, 1892
Pseudochthonius ramalho Assis, Schimonsky & Bichuette, sp. nov.
http://zoobank.org/5558E734-180A-43B0-B4D4-5BDA609AC030
Figs 3–8
Type material. Holotype: 1 ♂ (LES9601) B Caatinga province, Serra do Ra-
malho karst area, Serra do Ramalho, Bahia, Gruna do Vandercir cave; 13°38'11.40"S,
43°50'5.10"W; 31 May 2012; Bichuette ME, Gallão JE, Hattori N leg. Paratype: 1 ♀
(LES9602), same data as holotype.
Etymology. e species is named after the region of Serra do Ramalho due to its
importance regarding the speleological heritage and the unique fauna and ora diver-
sity. e name is to be treated as a noun in apposition.
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
114
Diagnosis. Pseudochthonius ramalho sp. nov. can be identied by the following
combination of characters: eyes absent (♂) or with eyes-spots (♀); the middle and
distal xed chelal nger teeth positioned two by two with 29–30 acuminate teeth and
3–4 slightly basally rounded ones, the presence of two rounded micro–denticles, along
with pedipalpal xed nger teeth in males; trichobothria ist closer to esb than to the est
(ratio ist-est/ist-esb = 4.71); serrula exterior with 13 (♂) or 14 (♀) lamellae, rallum with
seven blades, and coxae I and II with 3 to 5 coxal spines.
Figure 3. Holotype of Pseudochthonius ramalho sp. nov. in natural habitat, at Gruna do Vandercir cave,
Serra do Ramalho, Bahia. (Image: Adriano Gambarini).
Figure 4. Pseudochthonius ramalho sp. nov. holotype male, habitus A dorsal view B ventral view.
New troglobitic Pseudochthonius from Serra do Ramalho 115
Description (adult ♂ and ♀). Body: Coloration of specimens in 70% ethanol yel-
lowish brown and translucent pedipalps, tergites III–V with a dark median mark, and a
darker abdominal region. Live specimens present a light pinkish color on their carapace
and appendages, and a light brown abdomen. Female is slightly smaller than male.
Chelicera (Figs 6A, 7B, C): ve setae on left hand, with one seta on the basal
position of the xed nger and one nearly the basal seta on the movable nger; six
setae on the right hand; without the lateral microsetae; xed nger with 10–11 (♂
Figure 5. Pseudochthonius ramalho sp. nov. scanning electron images. Paratype female, habitus A dorsal
view B ventral view C zoom in on the anterior margin of the carapace with eye spots denoted with red
circle. (Images: Luciana B. R. Fernandes).
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
116
and ♀) teeth proximally reduced in size; movable nger with 9 (♂) or 8(♀) teeth
proximally reduced in size, three distal teeth distinctly larger than others and with
subapical isolated tooth (di). Spinneret moderately prominent and apically rounded
in female, vestigial in male. Seta gl 0.15 mm from base of movable nger. Serrula
exterior with 13 (♂),14 (♀) lamellae. Rallum with seven blades pectinated. Dorsal
face of cheliceral palm with four lyrissures, three lyrissures situated near seta dt and
one situated posteriorly.
Pedipalp (Figs 6B–D, 8A–F): 1.4 (♂),1.2 (♀) × longer than carapace and 2.2 (♂),
2.6 (♀) × longer than patella; movable nger 1.6 (♂), 1.9 (♀) × longer than hand;
xed nger 1.65 (♂),1.72 (♀) × longer than hand. Fixed chelal nger long and strong-
ly sigmoid in its distal half. Male xed nger with 33 acute teeth, distinctly separated
from each other, but paired and in each pair, one tooth is slightly directed to inside and
the other to the outside, and micro–denticles in two interdental spaces, on teeth 15
and 29, respectively. Female xed nger with 31 teeth arranged as in as in male. Mov-
Figure 6. Pseudochthonius ramalho sp. nov. female paratype scanning electron images A detail on the
right chelicera of serrula exterior and rallum B detail on the right pedipalp trichobothrium isb and ib,
lateral C left pedipalp D detail on the left pedipalp teeth. (Images: L. B. R. Fernandes).
New troglobitic Pseudochthonius from Serra do Ramalho 117
able nger with 30–33(♂ and ♀) attened and separated teeth. Trichobothria: ib and
isb situated close to each other sub–medially in the dorsal region of the chelal hand; eb
closer to esb than to ist, forming a straight oblique row at the base of the xed chelal
nger; ist closer to esb than to the est (ratio ist–est/ist–esb = 4.71); et slightly near the
tip of the xed nger, near to the chelal teeth; dx, located near to the end of the xed
nger; sb closer to b than to st in the movable chelal nger (ratio sb–st/sb–b = 3.37); t
closer to st and situated at the same level as est.
Carapace (Fig. 7A): Carapace 1.09× longer than broad, posteriorly constricted,
chaetotaxy 4:4:4:2:2 (16), one preocular microseta on each side; eyes absent on male
Figure 7. Pseudochthonius ramalho sp. nov., male A carapace dorsal view, and detail of the anterior mar-
gin (with the epistome) B right chelicera (dorsal view) C detail of the rallum D coxa I and II E details of
coxal spines F leg I (lateral view) G leg IV (lateral view).
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
118
and a tiny eyespot on female; anterior margin distinctly serrate with median denticles
larger than lateral ones; epistome prominent and dentate (Fig. 7A–C); 3 lyrissures
anteriorly, 1 medially and 2 posteriorly.
Abdomen: Chaetotaxy of tergites I–XI: ♂, 4: 4: 4: 4: 6: 6: 6: 6: 6: 5: 3; ♀, 4: 4: 4:
4: 5: 6: 6: 6: 6: 5: 3. Chaetotaxy of sternites III–XI: (♂/♀) 12: 13: 8: 8: 8: 8: 6: 5: 2,
anal cone 0/2 setae.
Genital area: Anterior genital operculum with 8 (♂), 9 (♀) marginal and discal
setae, arranged triangularly in male, with 7–8 unmodied marginal setae on each side;
posterior operculum with 6 setae in female.
Coxae (Fig. 7D, E): Manducatory process distally acute, with 2 setae; pedipalpal
coxa with 3 setae, coxa I and II with 4–5 setae on anterior margin and 3–5 highly
dented coxal spines in decreasing size distally, coxa III with 7 setae and coxa IV with 8
setae; intercoxal tubercle absent.
Figure 8. A holotype left pedipalp showing the trichobothria distribution B details of chelal teeth Cdis-
tal part of xed chelal nger (lateral view) D detail with emphasis on the micro–denticles in two interdental
spaces, on teeth 15 and 29, respectively E pedipalp femur F distal part of xed chelal nger (ventral view).
New troglobitic Pseudochthonius from Serra do Ramalho 119
Legs (Fig. 7F, G): Typical of the genus (Chamberlin 1929).
Measurements and ratios: see Table 1.
Taxonomic remarks
e new species Pseudochthonius ramalho sp. nov. is compared with other hypogean
and epigean Pseudochthonius species. It most resembles other Brazilian species of Pseu-
dochthonius that lack eyes, and occur in caves, like P. strinatii and P. biseriatus. Pseu-
dochthonius ramalho sp. nov. has 5 coxal spines, almost ever–increasingly arranged;
sternites V–VIII with 8 setae on sternal chaetotaxy; trichobothrium ist is 4× farther
from est than from esb; the middle and distal xed chelal nger teeth dier only in
their direction, but not in their size or shape, with teeth arranged two by two; male
is slightly larger; it has pedipalpal patella and pedipalpal femur proportionally larger
and smaller (4.1 ♂ and ♀). Dierently, Pseudochthonius strinatii has 2 longer and 2
shorter coxal spines; sternal chaetotaxy with 6 setae on each sternite; the position of
trichobothria ist is 3× farther from est than from esb; its xed chelal nger teeth show
heterodontism; pedipalpal patella and pedipalpal femur proportionally smaller (2.0 ♂)
and larger (5.3–6.1 ♂), respectively. Pseudochthonius biseriatus has 2 setae on tergites I
and II, a rallum with nine setae, and 37–41 teeth arranged in an oset manner; chelal
length 1.24–1.39. In contrast, P. ramalho sp. nov. has four setae on tergites I and II,
a rallum with seven blades, and chela xed nger with 30–33 teeth; chelal length
0.81–0.90. All three species share the unpigmented tegument with other troglobitc
Table 1. Measurements (in mm) and proportions (l/b, length/breadth; l/d, length/depth) of the holotype
male and paratype female of Pseudochthonius ramalho sp. nov.
Holotype (Paratype) Holotype (Paratype) l/b; l/d
Body 1.55 (1.45)
Carapace 0.46/0.42 (0.45/0.42) 1.1 (1.0)
narrower part posteriorly 0.27
(0.275)
Pedipalpal trochanter 0.18/0.12 (0.16/0.11) 1.6 (1.5) l/b
Pedipalpal femur 0.65/0.16 (0.54/0.13) 4.1 (4.1) l/b
Pedipalpal patella 0.29/0.15(0.25/0.12) 4.1 (2.1) l/b
Pedipalpal chela 0.90/0.20 (0.81/0.14) 4.5 (5.8) l/d
Pedipalpal hand 0.35/0.20 (0.29/0.14) 1.9 (2.1) l/d
Pedipalpal xed nger 0.58/0.05 (0.50/0.02)
Pedipalpal movable nger 0.57/0.04 (0.55/0.02)
Chelicera 0.39/0.19 (0.38/0.18) 2.1 (2.1) l/b
Chelicera movable nger 0.18 (0.17)
Leg I femur 0.35/0.06 (0.36/0.05) 5.9 (7.2) l/d
Leg I patella 0.18/0.05 (0.16/0.05) 3.6 (3.2) l/d
Leg I tibia 0.21/0.04 (0.15/0.04) 5.2 (3.8) l/d
Leg I tarsus 0.33/0.03 (0.29/0.03) 11 (9.6) l/d
Leg IV trochanter 0.18/0.16 (0.16/0.13) 1.1 (1.2) l/b
Leg IV femur + patella 0.76/0.28 (0.70/0.12) 2.7 (5.8) l/d
Leg IV tibia 0.38/0.08 (0.16/ 0.05) 4.7 (3.2) l/d
Leg IV basitarsus 0.19/0.05 (0.18/0.05) 3.8 (3.6) l/d
Leg IV telotarsus 0.35/0.03 (0.34/0.02) 11.6 (17) l/d
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
120
Pseudochthonius species, like P. troglobius and P. pulchellus (Ellingsen, 1902). However,
P. ramalho sp. nov. diers from these and from P. biseriatus and P. strinatii due the
presence of ocular spots in the female. Other nontroglobitic Pseudochthonius present in
Brazilian caves, have eyespots (P. gracilimanus Mahnert, 2001 and P. ricardoi Mahnert,
2001). Pseudochthonius troglobius has a pedipalpal xed nger with 65 teeth, and pro-
portionally larger body features (e.g., movable nger 2.14× longer than hand). is is
dierent from P. ramalho sp. nov. with 30–33 teeth in the xed pedipalpal nger and
a proportionally smaller body (e.g., movable nger 1.6× longer than hand). Consid-
ering the number of marginal teeth on the pedipalpal movable nger, P. ramalho sp.
nov. resembles P. gracilimanus and P. strinatii with 30–33 teeth (Beier 1969; Mahnert
2001), but it diers from the P. biseriatus (34–37), P. ricardoi (43), and the epigean P.
orthodactylus Muchmore, 1970 (7) (Muchmore 1970; Mahnert 2001). Also, Pseudoch-
thonius ramalho sp. nov. tarsus of leg I (9.6–11× longer than deep) is similar to other
brazilian cave-dwelling species like P. biseriatus (10.3–11.0), P. strinatii (9.5–10.7), P.
ricardoi (10.1) and is longer than the epigean species P. tuxeni (7.3) (Beier 1969; Mah-
nert 1979; Mahnert 2001).
Discussion
Distribution of the genus Pseudochthonius in Brazil
Species of Pseudochthonius occur in ve Brazilian states (Fig. 9): in the state of São
Paulo (southeastern Brazil) with representatives of P. strinatii and P. ricardoi in cave
habitats (Alto Ribeira karst area) and P. brasiliensis (in the region of Barueri); in state
of Minas Gerais (southeastern Brazil), with the troglobitic species P. biseriatus endemic
to the cave Olhos d‘Água; in the state of Bahia (northeastern Brazil), with the new
species described herein P. ramalho sp. nov., troglobitic and endemic of to Gruna do
Vandercir cave, and also P. gracilimanus in cave habitat; in the state of Pará (northern
Brazil) with representatives P. orthodactylus and P. tuxeni; and in the state of Amazonas
(northern Brazil) the species P. homodentatus has been found in the Ducke Reserve
and P. heterodentatus Ho, 1946 was registered in the Urucu river basin (Aguiar and
Bührnheim 1994). However, recently, this genus was recorded in other karst areas and
biogeographical provinces, increasing its distribution to 37 more caves (Schimonsky
and Bichuette 2019b).
Troglomorphic traits
Troglomorphic traits are characteristics that propose a relationship between hypogean
species and the subterranean environment, associated with behavior, physiology, and
mainly, morphology. Although these characteristics are useful to dierentiate hypo-
gean from epigean species, they do not explain the direct connection between the
subterranean habitats and the species that inhabit it (Juberthie and Decu 1994).
New troglobitic Pseudochthonius from Serra do Ramalho 121
Most families of pseudoscorpions have at least one troglomorphic feature. Chtho-
niidae can be considered one of the most important families regarding occurrence in
subterranean habitats (Harvey et al. 2000; Reddell 2012). e most common troglo-
morphic characteristics are eye reduction and cutaneous melanin depigmentation,
classied as regressive evolution (Christiansen 2012), in addition to progressive mor-
phological changes, such as appendages elongation, which is fundamental for spatial
orientation, defense, and predation in a habitat with the absence of light (Chamber-
lin and Malcolm 1960; Christiansen 2012). Examples of progressive morphological
changes could be the comparison in the proportional length of the dierent body parts
of dierent species, which highlights the appendages elongation, e.g., the tibia and the
tarsus and of leg I. e hypogean species Pseudochthonius ramalho sp. nov. (5.2× longer
than deep; 9.6–11× longer than deep), P. biseriatus (6.0× longer than deep; 10.3–11×
longer than deep), P. strinatii (4.8× longer than deep; 9.5–10.7× longer than deep), P.
ricardoi (5.3× longer than deep; 10.1× longer than deep). In the epigean species, P. het-
erodentatus (3.6× longer than deep; 10.0× longer than deep) and P. tuxeni (3.6× longer
than deep; 7.3× longer than deep). Nevertheless, the epigean fauna of pseudoscorpi-
ons in South America is still little known (Mahnert and Addis 2002), which makes it
Figure 9. Distribution of epigean and hypogean Pseudochthonius species in Brazil, with troglobitic rep-
resentatives detached.
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
122
dicult to compare hypogean and epigean individuals for the establishment of new
troglomorphic characteristics. e female of the new species P. ramalho sp. nov. has
ocular spots (Fig. 5) and the male has no ocular features. ese characteristics should
indicate a troglomorphic traits, that is, characters adapted to life in the subterranean
environment (Fong 2012). us, these features can be compared with other Brazilian
cave species (non–troglobitic), which have two small eyes (P. gracilimanus) or indistinct
eye spots (P. ricardoi). When compared with some epigean species (P. thibaudi Castri,
1983 and P. arabicus Mahnert, 2014) it is noted that the absence or reduction of ocular
traces is a troglomorphic trait (Fig. 10).
Pseudochthonius ramalho sp. nov. (Fig. 11A), P. strinatii (Fig. 11B) and P. biseriatus
(Fig. 11C) show a narrowing in the carapace from the anterior to the posterior margin
of the carapace of approximately 0.28 mm (anterior region 1.57× broad than longer),
0.26 mm (anterior region 1.61× broad than longer) and 0.29 mm (anterior region
1.37× broad than longer), respectively, when compared to the epigean Pseudochthonius
sp. (unidentied species) (Fig. 11D), which is about 0.41 mm wide (anterior region
0.92× broad than longer), this could be another troglomorphic trait, like the so–called
“false physogastry” in some cave beatles, like Leptodirini (Faille 2019).
In the pedipalpal chela of the three hypogean species, there is a slight decrease in
the length and width of the hand and a signicant increase in the length of the xed
nger. ese pseudoscorpions have, respectively, the following length and width: hand
(in mm) – 0.29/0.14 in P. ramalho sp. nov. (Fig. 11A1), 0.27/0.14 in P. strinatii (Fig.
11B1) and 0.26/0.13 in P. biseriatus (Fig. 11C1), and xed nger (in mm) –0.59/0.04,
0.63/0.03 and 0.54/0.03, respectively. ese values contrast with the ones observed
in the epigean species Pseudochthonius sp.: hand (in mm) –0.31/0.19 and xed nger
Figure 10. Morphological dierences on the carapace of hypogean and epigean species of Pseudochthoni-
us: eyes (denoted with red circle), and the narrowing of the posterior region of the carapace (marked with
dashed line on the sides of the carapace) A hypogean P. ramalho sp. nov. (male) B epigean P. thibaudi
Cepigean P. arabicus.
New troglobitic Pseudochthonius from Serra do Ramalho 123
(in mm) –0.49/0.04. Our observations corroborate that, for Chthoniidae, we cannot
infer troglomorphism concerning to a single character (such as body pigmentation),
but rather to a combination of traits (eyes/ocular structures, thinning of the cuticle,
proportionally longer body, pigmentation, and ratio pedipalpal femur/carapace).
Conservation remarks
e Serra do Ramalho region is formed by several masses of carbonate rocks, thus
enabling the occurrence of many karst features, including caves. Cave extensions range
from hundreds of meters to more than 5 km, some exceeding 15 km (Rubbioli et al
2019). Another record of great importance is the great potential regarding subterra-
nean fauna for both invertebrates and vertebrates (e.g., Baptista and Giupponi 2002;
Pérez and Kury 2002; Bichuette and Trajano 2004; Bichuette and Trajano 2005; Tra-
jano et al. 2009; Bichuette and Rizzato 2012). e issues related to the preservation
of the subterranean environments in this karst region are directly inuenced by the
corresponding epigean environment. As the subterranean organisms use allochthonous
organic matter, they rapidly suer from the eects of any changes that occur to the
epigean environment, e.g., deforestation and surface water pollution. us, studies
demonstrate that the vast diversity of subterranean fauna is extremely important as an
indicator of the health of the overall area (Bichuette et al. 2013; Gallão and Bichuette
2018). However, the Serra do Ramalho region is not yet inserted in any conservation
units (e.g., State Park) and it is exposed to risks such as deforestation (e.g., wood for
charcoal production), agriculture and mining projects due to the presence of rare met-
als (e.g., niobium) (Silva Junior and Campos 2016; Gallão and Bichuette 2018). e
exploration and extraction of these metals can destroy entire caves and systems, leading
to the extinction of isolated populations in these habitats (Culver 1986). is, coupled
Figure 11. Comparison of morphology among some species of Pseudochthonius from Brazil A Holotype
Pseudochthonius ramalho sp. nov. (troglobitic) (LES9601) and left chela (A1) B Pseudochthonius strinatii
(troglobitic) (LES9391) and pedipalp detail (B1) C Pseudochthonius biseriatus (troglobitic) (LES9434)
and pedipalp detail (C1) D Pseudochthonius sp. (epigean) (LES9629) and pedipalp detail (D1) (Images:
A D. M. von Schimonsky; A1–C1 L.B.R Fernandes; D–D1 M. E. Bichuette).
Leonardo de Assis et al. / Subterranean Biology 40: 109–128 (2021)
124
with the lack of laws that eectively protect caves in Brazil, leaves all this diversity of
habitats under a high level of threat.
Pseudochthonius ramalho sp. nov. occurs exclusively in Gruna do Vandercir cave,
being considered an endemic species to its type locality. By IUCN (International Un-
ion of Conservation of Nature) criteria, we classify this species as Critically Endan-
gered (CR) according to criteria B1ab (iii) + B2ab (iii). is means that the species
has a restricted geographical distribution, with an estimated occurrence of less than
100km² (B1) and 10 km² (B2), and the severely fragmented population (a) lives in a
few locations with the continued decline (b) in area, extension, and quality of habitat
(iii). erefore, eective protection measures must be taken so that there is no degrada-
tion of this environment, which is important in several aspects, and in this case, as the
limited habitat of unique species that are very sensitive to disturbances.
Acknowledgements
is study was nanced in part by the Coordenação de Aperfeiçoamento de Pessoal
de Nível Superior – Brasil (CAPES) (Finance Code 001) as a scholarship to LA; PRO-
TAX II project (Fundação de Amparo à Pesquisa do Estado de São Paulo / Fapesp
2016/50381–9 and CAPES 88887.159166/2017–00, project number 440646/2015–
4), FAPESP (process 2008/05678-7 and 2010/08459–4) and Conselho Nacional de
Desenvolvimento Cientíco e Tecnológico (CNPq) for research fellow (303715/2011–
1, 308557/2014–0 and 310378/2017–6) and regular project (457413/2014–0) to
MEB. We also thank: A.M.P.M. Dias, coordinator of Instituto Nacional de Ciência e
Tecnologia dos Hymenoptera Parasitoides da Região Sudeste Brasileira (INCT Hym-
par Sudeste – FAPESP 2008/57949–4 and CNPq 573802/2008–4) for making avail-
able the equipment and L.B.R. Fernandes for taking the SEM and stereomicroscope
images and for image editing; to the members of Laboratório de Estudos Subterrâneos
– LES, especially J. E. Gallão and N. Hattori for the collections of specimens and help
in the eld trips to Serra do Ramalho. To J. E. Gallão for critical reading and sugges-
tions to the work. To A. Gambarini for his eld assistance and the images of the new
species and the cave habitat. To Grupo Bambuí de Pesquisas Espeleológicas (GBPE)
for sharing information about Serra do Ramalho and to all support to MEB. To In-
stitituo Chico Mendes de Conservação da Biodiversidade (ICMBIO) for collecting
permit in caves (SISBIO 20165). We thank to Mark S. Harvey and János Novák for
their valuable suggestions and comments. We are also grateful to the reviewers Giulio
Gardini, André Lira, one anonymous reviewer and the subject editor Martina Pavlek.
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