Thalerommata margarita Osorio, Benavides, García-Atencia & Bertani, 2024, sp. nov.
Creators: name: Osorio, Luis M.
name: Benavides, Léiner
name: García-Atencia, Sandy
name: Bertani, Rogério
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Barychelidae
Thalerommata
Thalerommata margarita

description: Thalerommata margarita sp. nov.
(Figs 9–12, Fig. 13F).
Type material. Holotype ♂ from Colombia: Magdalena: Santa Marta, Minca, Vda. Bella Vista, ground hand collecting, subtropical humid forest (11°06’11.6”N, 74°04’18.1”W), 1880 m.a.s.l, 06 May 2023, L. Benavides & E. Bolaño leg. (ICN-Ar12996). Paratype 1 ♀, 2 immatures, same data as holotype (ICN-Ar12997).
Diagnosis. Males of T. margarita sp. nov. resemble those of T. kogui sp. nov. in having a curved metatarsus I with a protuberance in the distal prolateral region (Fig. 9D, E) and T. anae in the general aspect of the bulb (Fig. 10A, B). They can be distinguished from most of their congeners by having the tibia of the palpus elongate, not enlarged in the basal half, absence of spiniform setae and embolus more than twice the length of the tegulum (Fig. 10A–E) and of T. anae by having a curved metatarsus I with a protuberance in the distal prolateral region, tibial apophysis shape and embolus strongly curved at its middle half (Fig. 9D, Fig. 10 A, B). Females resemble T. maculata, T. caudicula, T. yukpa sp. nov. and T. kogui sp. nov. by having the distal article of PLS digitiform (Fig. 11D). They differ from all of the above species in having elongate spermathecae, thickened at their base and the absence of distal lobes (Fig. 12).
Etymology. The specific epithet comes from the Latin “margarita,” which translates to “Perla” in Spanish. This term, in turn, is an appellation given to the city of Santa Marta “La Perla de América”.
Description. Male holotype (ICN-Ar12996). Carapace 6.81 long, 5.97 wide. Abdomen 6.64 long, 3.53 wide. Total length 15.27. Carapace: fovea straight 0.76 wide (Fig. 9A). Clypeus absent. Eight eyes arranged on tubercle 1.28 wide, 0.78 long. MOQ 0.69 wide, 0.56 long. Anterior eye row slightly procurved, posterior row slightly recurved (Fig. 9A). AME 0.25, ALE 0.42, PME 0.18, PLE 0.33. Eye interspaces: AME–AME 0.14, AME–ALE 0.07, ALE–ALE 0.63, PME–PLE 0.04, PME–PME 0.53, ALE–PLE 0.12, PLE–PLE 0.95. Chelicerae: 1.82 long, with 12 large, spaced teeth and numerous tiny on basal inner edge. Intercheliceral intumescence absent. Rastellum composed of long thick setae. Labium ellipsoid, 0.65 long, 1.00 wide, with 44 cuspules rounded on anterior half (Fig. 9B). Labiosternal groove shallow, with a pair of sigilla (Fig. 9B). Maxillae (Fig. 9B): 1.90 long in front, 2.54 long behind, 1.20 wide, with ca. 56 cuspules on upper mound on inner angle. Heel distinct. Frontal lobe distinct, short. Prolateral edge whitish: (Fig. 9B). Sternum (Fig. 9B): 2.76 long, 2.81 wide. Three pairs of sigilla, rounded. First pair close to coxa I, second pair close to coxa II, and third pair close to coxa III. All sigilla distant, about one diameter from margin. Lyra and stridulatory apparatus absent. Abdomen: booklungs small with elliptical aperture ca. 0.70 in length, booklung combs absent. Spinnerets: PMS small, 0.55 long, 0.25 wide, 0.11 apart. PLS, basal segment, 0.73 long, 0.45 wide; middle 0.56 long, 0.41 wide; apical 0.76 long, 0.34 wide. Apical segment digitiform. Legs: IV–I–III–II. Legs (femur, patella, tibia, metatarsus, tarsus, total): I: 5.57, 3.50, 5.48, 3.97, 3.12, 21.64; II: 5.43, 3.19, 4.52, 4.28, 2.84, 20.26; III: 5.07, 2.52, 3.58, 4.76, 2.74, 18.67; IV: 6.57, 2.78, 5.27, 6.89, 2.90, 24.41; Palp: 2.46, 2.15, 2.96, -, 1.10, 8.67. Widths: I: 1.30, 1.38, 1.34, 0.73, 0.69; II: 1.26, 1.29, 0.77, 0.74, 0.52; III: 1.43, 1.25, 1.07, 0.70, 0.56; IV: 1.24, 1.12, 1.04, 0.61, 0.52; Palp: 1.14, 1.11, 1.33, -, 0.41. Spines: tarsi of legs lacking spines. Leg I: fe p0-0-2 r0-0-2, pa 0, ti p 0-1-2 v2-2-2, me p1-r1; leg II: fe p0-1-3, pa 0, ti p1-1-0 v2-1-3ap, me p0-1-0, v1-1- 2ap; leg III: fe d3-4-2, pa0, ti p1-1-1 r1-1-1 v2-2-3ap, me v4-3-3ap p1-1-1 r2-2-1ap; leg IV: fe d1-4-2, pa0, ti p1-2-1 r1-2-2 v3-3-3ap, me v3-4-3ap r1-1-1 p2-2-1; palp: fe 0, pa 0, ti p0-2-1 r0-0-1ap; cymbium 12 closely positioned at the apex. PC absent. Clavate trichobothria in two rows, on distal half: 10 on tarsus I; 7 on tarsus II, 14 on tarsus III; 19 on tarsus IV; 15 on palpal tarsus. Claws: STC with double row of 7–7 teeth on leg I; 8–7 on leg II; 7–7 on leg III; 8–8 on leg IV. Scopula: sparse on tarsi of legs I–IV; divided by broad row of setae on tarsi III–IV. Metatarsi I–III scopulate on apical third. Tarsi III–IV cracked. Tibial apophysis (Fig. 9D, E): Upper and lower process roughly at same level. Small lower process with small contiguous sinuous spine, two times process length. Upper process large, curved, with curved spine roughly same length of process. Very short sinuous upper spine, and more basal, long and sinuous spine, twice as long as short spine, positioned on broad and strong base. Both structures on prolateral face of tibia. Tibia I excavated prolaterally from area of apophysis to its tip. Metatarsus I curved, with small prolateral bulge (Fig. 9D, E), when folded it passes retrolaterally by apophysis. Palp (Fig. 10A–E): Bulb pyriform, with embolus that tapers abruptly in middle portion to its tip, with slight curvature to prolateral side. Tegulum 0.49 long, 0.20 wide, embolus 2.64 long, 0.31 wide at its base, 0.09 at middle, 0.03 at tip. Cymbium triangular in retrolateral view, not elongated, with deep incision. Palpal tibia with narrow excavation, spiniform setae absent. Color pattern (preserved in alcohol) (Fig. 9A, C): Carapace, chelicerae and legs brown, abdomen darker with ten whitish oval spots dorsally. Setae Type II (Ríos-Tamayo, 2024) only on abdomen, occurring both dorsally and ventrally.
Description. Female paratype (ICN-Ar 12997). Carapace 7.20 long, 6.45 wide.Abdomen 12.85 long, 8.16 wide. Total length 23.33. Carapace: Fovea straight 1.18 wide (Fig. 11A). Clypeus absent. Eight eyes arranged on tubercle 1.39 wide, 0.93 long. MOQ 0.93 wide, 0.67 long. Anterior eye row straight, posterior row slightly recurved (Fig. 11A). AME 0.22, ALE 0.39, PME 0.28, PLE 0.36. Eye interspaces: AME–AME 0.18, AME–ALE 0.10, ALE–ALE 0.77, PME–PLE 0.07, PME–PME 0.60, ALE–PLE 0.13, PLE–PLE 1.05. Chelicerae: 3.28 long, with 12 spaced teeth and numerous very small denticles on its base. Rastellum composed of long thick setae. Labium ellipsoid, 0.94 long, 1.37 wide, having 67 cuspules rounded, on the distal half (Fig. 11B). Labiosternal groove shallow, with pair of sigilla (Fig. 11B). Maxillae (Fig. 11B): 2.28 long in front, 3.52 long behind, 1.56 wide, with ca. 60 cuspules on upper mound in inner angle. Heel distinct. Frontal lobe distinct, short. Prolateral edge whitish. Sternum (Fig. 11B): 3.27 long, 3.63 wide. Three pairs of sigilla, rounded. First pair close to coxa I, second pair close to coxa II, and third pair close to coxa III. All sigilla distant, about one diameter from margin. Lyra and stridulatory apparatus absent. Abdomen: booklungs small with elliptical aperture ca. 0.81 in length, with booklung combs hardly visible. Spinnerets (Fig. 11D): PMS small, 0.84 long, 0.43 wide, 0.51 apart. Basal, middle, and apical segments of PLS, 1.37 long, 0.70 wide; 0.90 long, 0.68 wide; 1.27 long, 0.43 wide, respectively; apical segment digitiform. Legs: formula IV–I–II–III. Legs (femur, patella, tibia, metatarsus, tarsus, total): I: 4.98, 3.54, 3.66, 2.71, 1.91, 16.8; II: 4.56, 2.98, 3.29, 2.77, 2.24, 15.94; III: 4.17, 2.62, 2.60, 3.13, 2.16, 14.68; IV: 5.48, 3.01, 4.08, 4.86, 2.54, 19.97. Palp: 3.73, 2.71, 2.26, -, 2.42, 11.12. Widths: I: 1.12, 1.44, 1.46, 1.02, 0.92; II: 1.38, 1.28, 1.33, 0.96, 0.94; III: 1.72, 1.38, 1.40, 0.97, 0.77; IV: 1.32, 1.40, 1.35, 0.99, 0.83. Palp: 0.97, 1.24, 1.29, -, 0.94. Spines: leg I: fe:0, pa:0, ti0, me v1-0-1ap; leg II: fe0, pa0, ti0, me v1-0-1ap; leg III: fe0, pa0, ti p1-1-0 r0-0-1 v0-0-2ap, me p1-0-0 r0-2-2 v2-2-3ap; leg IV: fe0, pa0, ti p0 r0-1-1 v2-2-3ap, me p0-1-1 v2-2-3ap r0-1-1; palp: 0. PC absent. Clavate trichobothria in two rows on distal two thirds: 17 on tarsus I; 22 on tarsus II; 17 on tarsus III; 23 on tarsus IV; 16 on palpal tarsus. Claws: STC bare on all legs; palpal claw single, bare. Tarsi I–IV scopulate, divided by broad row of setae, metatarsus I–IV apically scopulate, on IV inconspicuous. Tarsi IV cracked. Spermathecae (Fig. 12): two, each with thick peduncle at base that tapers abruptly as it curves inward, with prolateral lobe. Color pattern (preserved in alcohol) (Fig. 11A–C): as in male. Setae Type II (Ríos-Tamayo, 2024) only on abdomen, occurring both dorsally and ventrally.
Distribution. Colombia: Magdalena Department, Minca, Vereda Bellavista, Sierra Nevada de Santa Marta (Fig. 13B, 14).
Natural history. Most specimens were collected in the San Lorenzo area (Fig 13B), with the exception of one male from Bella Vista area. The life zones of these localities belong to the very humid low montane forest and very humid subtropical forest, respectively (Tamarís-Turizo & López-Salgado, 2006). These sectors are located at altitudes between 1800 and 2900 m.a.s.l. and the climatic conditions in them give rise to average temperatures between 12–18⁰C, with average annual rainfall ranging between 2000–4000 mm and a geographical conformation that allows it to trap and condense cold air masses, so dense fogs usually form (Espinal, 1977; Guzmán, 1996). The vegetation is composed mainly of plants from the Melastomataceae, Orchidaceae, Araceae, Arecaceae, Chrysobalanaceae and Bromeliaceae families, as well as lichens and mosses (Cuadrado-Peña, 2005; Espinal, 1977). However, the abundance of Pinus patula, a species of pine introduced by the San Lorenzo Experimental Station, is notable (Granda & Del Portillo, 2007).
The individuals were found under logs and stones, in some cases in aggregate form, registering up to 5 individuals in an area of 0.06 m 2. In these conditions, mainly adult females and juveniles were found, with few males recorded. They were observed inside cavities in the form of ditches in the ground covered with silk and on the ground in slopes with abundant bromeliads. When disturbed, they tend to escape with rapid movements. Small beetles, crickets, and cockroaches were observed in the same microhabitat as these, as well as other mygalomorphs such as Kankuamo marquezi Perafán, Galvis & Gutiérrez, Striamea sp. and families of spiders of the infraorder Araneomorphae (LB pers. obs.).
Discussion. The species described here exhibit a digitiform apical segment of the PLS and a high number of labial cuspules (Figs. 3C–D; 7B–D; 11B–D), showing morphological affinities with T. maculata and T. caudicula. This suggests a close relationship between these species and supports the hypothesis of Nicoletta & Ferretti (2024), who consider that the type locality of T. caudicula may be an error and that its true geographic distribution could be associated with northern South America or the Caribbean. Records of the genus Thalerommata indicate a broad geographic distribution related to Caribbean countries, ranging from its northernmost points in the Bahamas to its southernmost points in Colombia (Bertani & Raven 2023). This suggests the potential distribution of these tarantulas between Central America and northern South America.
Shared characters between the genera Trichopelma and Thalerommata are evident, e.g., the distal article of PLS being short (Bertani & Raven 2023). However, the new species described herein confirms the variability of this character in Thalerommata. Additionally, Mori & Bertani (2020) recorded the presence of a thickening in the metatarsus of leg I of Trichopelma nitidum, referred to as the metatarsal bulge; this character is also present in T. kogui sp. nov. and T. margarita sp. nov. Similarly, Raven (1985) grouped Thalerommata and Trichopelma within the basal barychelids, suggesting that this should be considered in future phylogenetic studies involving these two genera. Fruitful studies will no doubt emerge on a possible sexual function of this characteristic, due to its exclusive position on leg I of males and its proximity to the tibial apophyses, important features in the sexual behavior of several mygalomorph spiders (Ferretti et al., 2013).
The species T. anae and T. margarita sp. nov. exhibit bulbs with a similar appearance but differ by the embolus being strongly curved towards the ventral face in T. margarita sp. nov. This characteristic, along with the vast geographical distance separating these species by a barrier like the Caribbean Sea, the altitudinal differences with respect to sea level in the ecosystems they inhabit, and the difference in the number of labial cuspules, support the hypothesis that they are two distinct species. The long and slender appearance of the embolus in males of T. margarita sp. nov. and T. yukpa sp. nov. could be an adaptation to the long spermathecal receptacles of their conspecific females, a common phenomenon in various spiders (Eberhard & Huber, 2010). It is hypothesized that the unknown female of T. anae will also have elongated spermathecal receptacles. Other morphological characters such as tibial apophysis shape, bulb morphology, modified abdominal setae, presence or absence of spines on the cymbium, leg scopula, presence or absence of teeth on STC, presence of palpal claw tufts on females, number of cuspules on labium and maxillae are in agreement with the other species in the genus (Bertani & Raven 2023).
Two of the three newly described species (T. kogui and T. margarita) come from the Sierra Nevada de Santa Marta (Fig. 13A), a small region of Colombia recognized as a biodiversity hotspot. This highlights how the genus Thalerommata remains poorly known. With the inclusion of these three species, Colombia now hosts 7 of the 11 known Thalerommata species. Undoubtedly, more new species will be discovered with further fieldwork in South America and the Caribbean, as well as investigations of unidentified specimens within collections. Thalerommata appears to be a very diverse genus with the potential to harbor additional species awaiting description.
description: Published as part of Osorio, Luis M., Benavides, Léiner, García-Atencia, Sandy & Bertani, Rogério, 2024, Three new species of tiny tarantulas of the genus Thalerommata Ausserer, 1875 (Araneae, Theraphosidae) from northern Colombia, pp. 95-114 in Zootaxa 5537 (1) on pages 106-111, DOI: 10.11646/zootaxa.5537.1.5, http://zenodo.org/record/14239357