Rowlandius ufpi, Silva & Santos & Carvalho, 2024

Silva, Iara Siqueira Santos, Santos, Adalberto J. & Carvalho, Leonardo Sousa, 2024, A potentially endangered new species of the genus Rowlandius (Arachnida: Schizomida: Hubbardiidae) from Northeastern Brazil, Zootaxa 5458 (3), pp. 403-419 : 405-417

Rowlandius ufpi sp. nov.

Figures 1–58

Rowlandius sp. , Ontano et al. (2021): 2459, fig. 10f.

Type material. HOLOTYPE: BRAZIL. Piauí: Floriano, Fazenda do Colégio Técnico de Floriano, riverine forest along the Parnaíba River margins, 109 m. a.s.l. (6°45’33.2”S, 43°3’17.9”W), L.S. Carvalho leg., 20/II/2020, 1 heteromorphic ♂ (CHNUFPI 4056) . PARATYPES: same locality and collector as holotype, 13/II/2020, 1 ♀, 17 imm. (CHNUFPI4055), 20/II/2020, 1 homeomorphic ♂ 1 ♀ f 2 imm. (CHNUFPI4057), 12/II/2020, 1 ♀ f (CHNUFPI 4211), L.S. Carvalho & R. F. Ferreira leg., 20/II/2020, 1 heteromorphic ♂ 1 ♀ f (CHNUFPI 4064), 1 heteromorphic ♂ 5 ♀ f (CHNUFPI 4065); same municipality and collector as holotype, Fazenda do Colégio Técnico de Floriano , gallery forest along small water stream (6°45’42”S, 43°3’17”W), 13/II/2012, 4 ♀ f (CHNUFPI 0676), 1 ♀ f (CHNUFPI 0677), 30/I/2013, 1 homeomorphic ♂, 1 ♀ f (CHNUFPI 0678), 13/II/2012, 1 homeomorphic ♂ (CHNUFPI 0679), 1 ♀ f (CHNUFPI 0680), 1 ♀ f (CHNUFPI 0681), 30/I/2013, 1 ♀ f (CHNUFPI 2699), 30/I/2013, 1 homeomorphic ♂, 1 imm. ( UFMG 29800 ), 30/I/2013, 1 homeomorphic ♂ ( UFMG 29793 ) .

Other examined specimens. BRAZIL. Piauí: Floriano, Fazenda do Colégio Técnico de Floriano, riverine forest along the Parnaíba River margins, 109 m. a.s.l. (6°45’33.2”S, 43°3’17.9”W), I.S.S. Silva & T. C. Santos leg., 20/II/2020, 1 homeomorphic ♂ 2 ♀ f (CHNUFPI 4058), L.S. Carvalho et al. leg., 10/II/2021, 1 heteromorphic ♂ (CHNUFPI 4059), 1 ♀ f (CHNUFPI 4060), L.S. Carvalho & R. F. Ferreira leg., 20/II/2020, 1 heteromorphic ♂ 1 ♀ f (CHNUFPI 4063), 1 heteromorphic ♂ 1 homeomorphic ♂ 1 ♀ f (CHNUFPI 4066), 3 ♀ f 1 imm. (CHNUFPI 4067), L.S. Carvalho leg., 20/XII/2022, 1 ♀ f (CHNUFPI 4210), same collector, 20/XII/2022, 2 ♀ f (CHNUFPI 4212), 1 heteromorphic ♂ (CHNUFPI 4239), 1 ♂ heteromorphic (CHNUFPI 4245) .

Etymology. The specific name is a noun in apposition taken from the acronym of the Universidade Federal do Piauí. The university owns the type-locality area and supported the present study.

Diagnosis. The flagellum of males of Rowlandius ufpi sp. nov. is subquadrate, as in R. linsduarteae and R. potiguar , but differs in the dm1 setae located on the basal third of the bulb ( Figs 22–24 ), whereas in R. linsduarteae and R. potiguar it is located on the pedicel. It also resembles R. ubajara by the rounded sides, but differs in the long postero-median dorsal protuberance with the dm4 setae at the posterior end ( Figs 17–19 ), whereas it is short in R. ubajara . The flagellum of R. ufpi sp. nov. is similar to that of R. pedrosoi by the protuberance in the postero-median region, differing from the latter by the postero-median protuberance connected to the dorso-lateral depressions, whereas in R. pedrosoi the protuberance is distal to the depressions. Additionally, the male flagellum of R. ufpi sp. nov. is longer than the length of the pedicel, with the vl2 setae proximal to the dl3 level and vl1 posterior to vm4, and vm5 distant from vl1. The female spermathecae is similar to that of R. ubajara by the long and thin median lobes, and similar to R. potiguar , R. pedrosoi and R. linsduarte by the developed bulbs of the lateral lobes. The females of R. ufpi sp. nov. ( Figs 46–50 ) can be differentiated by the combination of: (1) highly developed lateral lobes, which are attached to the chitinized arch by very thin stalks; (2) elongated and very thin median lobes; and (3) anterior portion of the chitinized arch with an obtuse (>150º) v-shaped angle.

Description. Heteromorphic male (holotype, CHNUFPI 4056). Coloration ( Fig. 1 ): general pattern greenish-brown. Prosoma is light brown; pedipalp and chelicerae reddish brown. Venter pale green. Legs: coxae I–IV brownish; trochanter I light red and II–IV greenish; femur I–IV greenish brown; patella I slightly reddish and II–IV greenish brown; tibia I reddish and II–IV light brown; tarsus I reddish and II–IV light brown. The opisthosoma and the flagellum are dark green.

Prosoma ( Figs 1 , 7, 9, 11 ). 1.5 long, 0.6 wide. Dorsal region: anterior process of propeltidium with 1+1 setae followed by 2 pairs of dorso-submedian setae; the tip of the process is bent downwards. Propeltidium 2 times longer than wide; eyespot present; metapeltidium entire, much wider than long and totally bristle-less. Ventral region: sternum anteriorly with 13 setae and posteriorly with 6 setae.

Chelicerae ( Figs 15–16 ). Movable finger sharp and curved distally, guard tooth present, serrula composed of 12 hyaline teeth, and a row of 15 long setae. Fixed finger with one basal tooth, followed by five small teeth of similar size and one larger distal tooth, curved tooth with acute apex. Setation: G1 with three spatulate setae; G2 composed of five feathered setae, and long setae, almost the length of the moving finger; G3 with four regular, cylindrical setae; G4 consisting of two smooth and short setae with thin apex; G5 (A) with seven similar setae; G5 (B) with six setae along the ventral border; G6 with one smooth setae, longer than half of movable finger length; G7 with six setae. Setal group formula: 3–5–4–2–(7+6)–1–6.

Pedipalp ( Figs 13–14 , 20, 21 ). Setation described in detail for homeomorphic male. Trochanter: Subcylindrical in retrolateral view, longer than wide, with apical portion curved upwards; with 12 ventral setae, a ventral row of large setae with an intermediate row of small setae. Femur: subcylindrical, curved in the basal portion, club-shaped, 9.2 times longer than wide and with distal portion three times longer than basal part; the femur is longer than the total length of the prosoma (pro-, meso- and metapeltidium together) and longer than the patella; with a dorsal row of setae. Patella: subcylindrical, club-shaped, with distal portion twice as wide as the basal part; with more setae than the femur, with two dorsal and two ventral rows; 3.3 times longer than high. Tibia: cylindrical, straight, with slightly wider distal portion; shorter than half the length of the femur; base as high as patella, with at least two ventral, one lateral, two dorsal setae; tibia has the largest number of setae on the pedipalps. Tarsus: conical, approximately half the length of tibia, with numerous setae (dorsal and lateral smooth, and ventral plumose). Pedipalp tarsal spurs asymmetrical, as long as half for the length of tarsal claw; tarsal claw sharp and curved.

Opisthosoma ( Figs 8, 10, 12 ). Setae: Tergites I–IX each with a dorsal pair of large Dm setae. Tergites XI–XII telescopic. Segment VIII with a pair of dorso-submedian setae and a pair of Dl1 and a pair of Dl2 setae; IX with pairs Dl1 and Dl2, Vm1, Vm2 and pair Vl1 and Vl2 present. Segments X–XII same as IX. Segment XII with the medial Vm1 and Vm2 shorter than Vll; with postero-dorsal opisthosomal process short, subtriangular.;Sternites I and II with numerous small setae; sternites III–VII with medium setae; sternites VIII–XII with large setae.

Flagellum ( Figs 17–19 , 22–24 ). Setation Dm1, Dm4; Dl1, Dl3; Vm1, Vm2, Vm4, Vm5; Vl1, Vl2. Shape subquadrate with rounded and dorsoventrally flattened sides, with the posterior region slightly tapered. With three projections: a pair located in the dorso-submedian region (between the setae Dl1 and Vm5), without setae, separated by a depression and a projection positioned in the posteromedian region, connected to the lateral ones, with the setae Dm4 at its apex. Setation: Dm4 proximal of the posterior margin on a protuberance; Vm1 at the same level as Dm1; Vm4 proximal to Vl1 level; Dl1 at same level to Vl1; Vm5 proximal to Dm4; Vl2 proximal to Dl3 level. One pair of dorsolateral microsetae between Dm1 and Dl1; six lateral microsetae between Dl1 and Dl3.

Homeomorphic male (paratype, CHNUFPI 0678). Chelicerae reddish and flagellum light brownish. Pedipalps: trochanter, femur, patella and tibia light reddish-brown; tarsus dark reddish-brown. Legs: coxae I–IV, sternum light brown; trochanters I reddish and II–IV greenish-brown; femur I reddish and II–IV greenish-brown; patellae I reddish and II–IV light greenish-brown; tibiae II–IV light brownish-brown, except for tibia I that is reddish; tarsus I light reddish and II–IV greenish-brown. Prosoma light brownish with propeltidium reddish-brown, meso and metapeltidium yellowish-brown, opisthosomal tergites greenish-brown and sternite light brownish.

Prosoma ( Figs 2 , 27, 29 ). 1.37 long, 0.62 wide. Anterior process of propeltidium with 2 setae (one behind the other) followed by 2 pairs of dorso-submedian setae transversally oriented. Propeltidium 1.8 times longer than high. metapeltidium entire. Chelicerae ( Figs 15–16 ), opisthosoma ( Figs 2 , 28, 30 ) and flagellum ( Figs 33–35 ) as in the male holotype.

Pedipalp ( Figs 25–26 , 31–32 ). Dorsal and lateral setae of tarsus smooth, ventral setae plumose. Trochanter: with ten ventral setae; prolaterally with an acute mesal spur (MS). Femur: subcylindrical, 2.3 times longer than high; dorsal edge with a row of eight setae; retrolaterally with Fe1, Fv1, Fv2, Fe2; prolaterally with Fvr with setae 1, 2 and 3, and with Fd1, Fd2. Patella: cylindrical, straight, 3.3 times longer than high, with 1 row of dorsal setae, 1 row on lateral and 2 rows on ventral; prolaterally with Pm1, Pm3, Pm4 and Pm5, surrounded by small pores; retrolaterally with Pe2, Pe3 and Pe5. Tibia: cylindrical, straight, 3 times longer than high, base as high as patella, with at least 2 ventral, 1 lateral, 2 dorsal setae; Ter with setae 4, 5 and 6; Tir with setae 1, 2, 3 and 4; Tmr with setae 2, 3 and 4; one other Tm1 setae; Tarsus: conical, with asymmetrical spurs (prolateral and retrolateral tarsal spurs: pTS/rTS); approximately half the length of tibia, with numerous setae. Tarsal claw sharp and curved, smaller than half the tarsus length.

Female (paratype, CHNUFPI 4064). Coloration and setation as in the male holotype. Propeltidium longer than wide ( Table 1 ). Prosoma ( Figs 3 , 36, 38 ), chelicerae and opisthosoma ( Figs 3 , 37, 39 ) as in the male holotype. Pedipalp similar to homeomorphic male.

Flagellum ( Figs 40–42 , 43–45 ). With 4 flagellomeres and 3 annuli, 4.6 times longer than wide. Flagellomere II with Dm1, Vm1 and Vm2 present. Flagellomere III with Vm4. Flagellomere IV with Vl1 at the same level Vm5 and Dl1; Dl1 between level of Vl1 and Vm5; Dm4 between Dl1 and Dl3; Vl2 slightly proximal to Dl3 and distal to Dm4.

Spermathecae ( Figs 46–50 ). Chitinized arch evident; closed and formed by anterior and posterior portions; anterior portion with an obtuse (>150°) v-shaped angle; posterior portion with a gonopod medially; pointed laterally. One pair of lateral lobes (LL) with long, thin stalks whose bases are separated by a distance greater than their length; with the bulb globose and oriented towards the middle; the median lobes (ML) short, with a thin base. Gonopod present, hyaline, directed posteriorly.

Distribution. This species is known only from the type locality ( Figs 51–58 ). This record fills a gap in the geographic distribution of Rowlandius in South America (see Fig. 58 ).

Variation. Number of individuals measured ( Table 1 ): heteromorphic male (N=5), homeomorphic male (N=5) and female (N=5). Total length: heteromorphic male 2.54–3.6 mm, homeomorphic male 3.02–3.6 mm, female 3.44– 5 mm. Length of pedipalpal femur: heteromorphic male 0.87–1.7 mm, homeomorphic male 0.47–0.6 mm, female 0.5–0.75 mm. Length of pedipalpal patella: heteromorphic male 1.2–1.95 mm, homeomorphic male 0.6–0.75 mm, female 0.47–0.65 mm ( Table 1 ). No relevant variation was observed in the pedipalp and flagellum setation of male specimens. The female spermathecae revealed a slight variation in the orientation of the median lobes, and in the position and shape of the lateral lobe bulbs ( Figs 47–50 ). The orientation of the bulbs can be different due to piece preparation, owing to the very thin stalk to which the bulb is attached. The gonopod might be challenging to observe owing to its weak sclerotization and destructive effects of specimen preparation.

Natural history. In February 2020, a female carrying her offspring on her opisthosoma was collected. The hatchling cluster presented 17 postembryos attached to the ventral side of the female opisthosoma ( Figs 4–6 ). After collection, the clutch detached from the opisthosoma, but the female did not grab it back. All the embryos were parallel to each other and in the same direction ( Figs 4–6 ).

Conservation assessment. This species has been under observation for ten years in its type-locality, in gallery and riverine forests within the Cerrado (savanna) domain (or Cerrado province sensu Morrone 2017), northeastern Brazil. The type-locality comprises a mosaic of approx. 200 hectares of pastures, corn, and banana crops, goat and cattle livestock, and secondary and primary patches of several natural phytophysiognomies. The vegetation patches are all typical of the Cerrado domain, including savannas (‘Cerrado strictu sensu ’), evergreen broad-leaved woodland (‘Cerradão’), seasonally dry tropical forests, riverine and gallery forests following the watercourses.

The individuals collected in 2012 and 2013 were found in very dense leaf litter of a gallery forest, situated very close (<5 m) to a small temporary stream. However, sampling events conducted by the same collectors, during the dry season in 2012, 2013 and 2014 failed to find any individuals in the same site. We hypothesize that the individuals were buried in the ground at that time, as a strategy to protect themselves from desiccation. This hypothesis contrasts with a study carried out with Rowlandius potiguar in captivity ( Oliveira & Ferreira 2014). The authors reported that individuals have the ability to dig their own nests, a behavior suggested to be rare in natural conditions due to the high availability of shelters ( Oliveira & Ferreira 2014). Future behavioral studies should address the effects of shelter availability, humidity, and substrate granulometry as triggers for digging behavior.

Around November 2017, the sampling site was severely damaged due to slash-and-burn agricultural practices (compare Figs 56 and 57 ). The secondary gallery forest was subsequently replaced by a banana crop upstream in the gallery course, and the exact same site where the schizomids were collected was highly disturbed. Despite additional collecting attempts in April 2018 and on several occasions in 2019, both at the original site and other locations nearby (mostly in gallery forests; Fig. 55 ), no additional individuals were found. In 2020, schizomids were found again, in a very limited area of about 100 x 30 m, within the riverine forest of the Parnaíba River, approx. 250 m from the initial site ( Figs 55–57 ).

The available data suggests that this species should be considered as critically endangered, in accordance with the criteria B1B2ab (iii+iv) of the IUCN Red List ( IUCN 2001). The reasons include: (1) the estimated occurrence extension of this species is less than 1 km ²; (2) the species has only one known population; (3) decreasing habitat quality due to human activities; (4) absence of the species within conservation units; and (5) possibility of extinction of the species based on a single slash-and-burn, fire or flooding event. Additionally, further samplings should be carried out upstream and downstream the Parnaíba River, looking for relatively well-preserved riverine and gallery forests, in order to search for additional locations for this species and provide further data for a reassessment of its conservation status.

The conservation status proposed for Rowlandius ufpi sp. nov., is not unprecedented. Several other Schizomida species have been suggested to be under differing threat categories (see Teruel 2012; Armas et al. 2017; Ruiz & Valente 2017; Castillo-Figueroa et al. 2024). Recently, schizomids have been shown to be associated to environmental characteristics and highly sensitive to environmental changes ( Castillo-Figueroa et al. 2024). However, no previous study provided robust evidence of the effects of habitat quality decrease on schizomid populations.Herein, we showed that habitat degradation could lead to local extinction of schizomids. This allowed two conclusions: (1) epigean schizomids from savanna biomes might not be found outside ideal conditions provided by forested environments; and (2) these species require a good habitat quality to be preserved. Further studies should evaluate the effect of recovering degraded riverine and gallery forests to evaluate the reestablishment of schizomid populations, at previously reported localities.

Rowlandius ufpi sp. nov. stands out among most Brazilian schizomids because it has not been collected inside a conservation unit, neither inside caves, nor in forested biomes (e.g., Amazon and Atlantic forests). On the contraire, the new species was found in the leaf litter within a savanna biome. Its conservation status might be shared in some degree with other South American species, considering their usually narrow distribution range and the fact that several species are known only as a byproduct of other taxa sampling (e.g., Pinto-da-Rocha 1996; Bonaldo & Pinto-da-Rocha 2007; Santos et al. 2008; Ruiz & Valente 2017, 2019). The fact that all our recent field work has resulted in the discovery of an undescribed species, rather than new records of species previously known (or introduced species), suggest that its narrow distribution pattern is not necessarily a result of sampling deficiency. This implies that more (potentially endangered) species await discovery, and highlights the relevance of long-term sampling for properly describing schizomid species. In fact, the first heteromorphic male was collected only eight years after the first homeomorphic male and female of the newly described species.

Note. Rowlandius ufpi sp. nov. belongs to the Rowlandius dumitrescoae species group. The diagnosis of this species group was revised by Giupponi et al. (2016), who considered the absence of a gonopod a distinctive character. However, these authors missed the presence of a gonopod described and illustrated for R. potiguar (see Santos et al. 2013: figs 4G, 6F). The presence of a gonopod in Rowlandius ufpi sp. nov. suggests that this structure might be present in other species of the group, for which it has not been reported. This absence might be explained by difficulties in visualizing this hyaline structure (compare Figs 47–50 ).

Figures

FIGURE 58. Known geographic distribution of described schizomid species from continental South America, including the Rowlandius ufpi sp. nov. (red circle), the remaining Rowlandius taxa (yellow squares) and other taxa (blue triangles).

FIGURES 1–6. Rowlandius ufpi sp. nov., habitus of heteromorphic (1) and homeomorphic male (2), female (3) and embryo clutch (4–6). Photos: L.S. Carvalho (1, 4–6) and P.H. Martins (2–3).

FIGURES 7–14. Rowlandius ufpi sp. nov. heteromorphic male, holotype (CHNUFPI 4056), dorsal (7–8), ventral (9–10) and lateral (11–12) habitus; prolateral (13) and retrolateral (14) views of the right pedipalp. Scale bars: 0.5 mm.

FIGURES 15–19. Rowlandius ufpi sp. nov., heteromorphic male, holotype (CHNUFPI 4056), chelicerae (15, 16) and flagellum (17–19), prolateral (15, 16), dorsal (17), ventral (18) and lateral (19) views. Scale bars: 0.1 mm (15–16), 0.5 mm (17–19).

FIGURES 20–26. Rowlandius ufpi sp. nov., heteromorphic male (20–24) holotype (CHNUFPI 4056) and homeomorphic male (25–26) paratype (CHNUFPI 0678), right pedipalp (20–21; 25–26) and flagellum (22–24), schematic drawings in retrolateral (20, 25), prolateral (21, 26), ventral (22), dorsal (23) and lateral (24) views. Scale bars: 0.5 mm.

FIGURES 27–35. Rowlandius ufpi sp. nov. homeomorphic male, paratype (CHNUFPI 0678), habitus (27–30), right pedipalp (31–32) and flagellum (33–35), in dorsal (27–28, 33) and ventral (29–30, 34), retrolateral (31, 35) and prolateral (32) views. Scale bars: 0.5 mm.

FIGURES 36–42. Rowlandius ufpi sp. nov. female, paratype (CHNUFPI 4064), habitus (36–39) and flagellum (40–42), in dorsal (36–37, 40) and ventral (38–39, 41) and retrolateral (42) views. Scale bars: 0.5 mm.

FIGURES 43–46. Rowlandius ufpi sp. nov. female, paratype (CHNUFPI 4057, flagellum (43–45): dorsal (43), ventral (44) and lateral (45) views; and internal genitalia (46). Scale bars: 0.5 mm (43–45), 0.1 mm (46). Abbreviations: APA, anterior portion of the chitinized arch; B, bulb; G, gonopod; LL, lateral lobes; ML, median lobes; PPA, posterior portion of the chitinized arch; S, stalk.

FIGURES 47–50. Rowlandius ufpi sp. nov. female, paratypes, variation in the internal genitalia. 47: CHNUFPI 4064; 48: CHNUFPI 4057; 49: CHNUFPI 4211; 50: CHNUFPI 4065. Scale bars: 0.1 mm.

FIGURES 51–54. Environments at the type-locality of Rowlandius ufpi sp. nov.. 51–52: Riparian zone, where the examined specimens were found. 53–54: Phytophysiognomies where no schizomid was observed, savanna (Cerrado stricto sensu; 53) and seasonally dry tropical forest (54).

FIGURES 55–57. Sites sampled in the search for Rowlandius ufpi sp. nov. specimens. 55: Overview of the area including the type-locality (yellow square), the 2012–2013 sampling site (yellow triangle) and searched sites where no specimen was found (white circles). 56: Google Earth image of the type-locality in December 2013, depicting the preserved riparian forest in both sampling sites where R. ufpi sp. nov. specimens were observed. 57: Google Earth image from August 2020, after the riparian forest being cleared and burnt in the 2012–2013 sampling site, where R. ufpi sp. nov., no longer occurs. Image sources: Esri, Maxar, Earthstar Geographics, the GIS User Community and Google Earth.