Dorsal Scutum Research Articles

Filling a geographic gap: a new species of genus Lacronia Strand, 1942 (Opiliones, Gonyleptidae) from southern Brazil

Despite the significant amount of systematic research on Gonyleptidae since its original description almost 200 years ago by Sundevall in 1833, there are still unresolved phylogenetic relationships that require further investigation. Current knowledge of the unranked clade DRMN (Gonyleptidae), consisting of Discocyrtus Holmberg, 1878 sensu stricto, Roeweriinae Carvalho & Kury, 2018, Mitobatinae Simon, 1879 and Neopachylinae Carvalho & Kury, 2020, has been advancing at strides. Recently, the genus Lacronia Strand, 1942, with species occurring along the south and southeastern Brazilian coast, underwent revision, resulting in keys and diagnoses for its species. In this article we describe Lacronia utaru sp. nov., a new species from Paraná State, which fills the supposed gap between previously discontinuous known occurrences of the genus. This new species is morphologically closer to the ‘not areolated Lacronia’ internal clade, especially to the type species Lacronia serripes (Mello-Leitão, 1923). Differences between L. serripes and L. utaru sp. nov. about the pattern of light-colored tubercles on the dorsal scutum are pointed out. Additionally, we present new records for two other species of Lacronia.

The first harvestman described from Bocas del Toro Archipelago: a new Poecilaemula (Opiliones: Cosmetidae) and notes about the genus

ABSTRACT The discovery of a new Cosmetidae species from Bocas del Toro Archipelago, Panama, with unusual sexual dimorphism and colouration, presented an identification challenge due to the limited knowledge of the taxonomy of cosmetids in Central America. The new species is notable for the extensive bright orange blots on the dorsal scutum and by the unusual structure of tibia IV of males, which is not incrassate, and bears two compact rows of strong spines. After examination of both type and non-type specimens of the type species of the genus Poecilaemula Roewer, 1912 (Meterginus signatus Banks, 1909), we decided that the new species should be assigned to this genus, and that the current circumscription of the genus is debatable as a natural group. Here, we propose a new definition of Poecilaemula, which includes three species: the type species from Costa Rica; Poecilaemula iching sp. n. from western Panama; and the species Poecilaemula eutypa (Chamberlin, 1925) comb. n. from eastern Panama, which is newly transferred from Paecilaema C.L. Koch, 1839. Additionally, Paecilaemana reimoseri Roewer, 1933 is considered a new junior subjective synonym of Meterginus signatus Banks 1909 (currently under Poecilaemula). The five South American species currently included in Poecilaemula reveal a geographic discrepancy, and they should be transferred to other genera in future investigations because they do not share any special similarity with the type species of the genus. http://www.zoobank.org/urn:lsid:zoobank.org:pub:0101B1EE-CF5F-4781-96FF-E797C71CF05C

On the genus Tegestria Roewer, 1936, new senior synonym of Gintingius Roewer, 1938 with the description of a new species (Opiliones: Epedanidae: Sarasinicinae).

Tegestria altmannae sp. nov. is described and illustrated based on male and female specimens collected in Malaysia. It is characterized by the unarmed dorsal scutum, and basal segment of chelicerae dorsally with three seta-tipped tubercles. The type species of the monotypic genus Gintingius Roewer, 1938, G. robustus Roewer, 1938, is treated as a new synonym of Tegestria coniata Roewer, 1938 and the genus Gintingius as a new synonym of Tegestria Roewer, 1936, accordingly.

A subterranean new genus and species of Eutrombidiinae (Trombidiformes: Microtrombidiidae) from Turkey

A new genus and species of the Microtrombidiidae, Troglotrombidium dolichopodum n. gen. et n. sp. is described based on ectoparasitic larvae collected from two Dolichopoda lycia (Galvagni 2006) (Orthoptera: Rhaphidophoridae) specimens from a cave in Western Taurus Mountains, Turkey. The new genus can be distinguished from other genera by the absence of eyes, highly modified claws of tarsi III, sensillary setae structure of the anterior dorsal scutum, and the number of adoral setae. The new species is a typical troglobite, and this interspecific interaction is a well-documented case for the little-known host-parasite relationships from subterranean ecosystems.

Two new species of Neogonyleptes Roewer, 1913 (Opiliones: Gonyleptidae: Pachylinae) from the Nahuelbuta mountain range, Chile.

Two new species of the Chilean endemic genus Neogonyleptes Roewer, 1913 are described based on specimens obtained in the Nahuelbuta mountain range, Biobo and La Araucana Regions. The new taxa are morphologically allied to Neogonyleptes karschii (Srensen, 1902); however, both differ from all species of the genus by their dorsal scutum area III+IV, which is armed with a large, apically bifurcate apophysis. Neogonyleptes floresi sp. nov. differs from N. pedrazai sp. nov. principally in the slender body and legs, the proximal constriction of the scutal apophysis, and the distally straight prolateral apophysis on coxa IV. Detailed descriptions, illustrations, and comparisons of the new species are given. Additionally, some comments are provided about the taxonomy of Neogonyleptes and allied genera.

Review of Paradiscocyrtus Mello-Leitão, 1927 (Gonyleptidae, Opiliones), with the transfer of Paradiscocyrtus cerayanus Roewer, 1929 to Discocyrtus Holmberg, 1878 and a new interpretation of its type locality

After the type species of Paradiscocyrtus Mello-Leitão, 1927 (Paradiscocyrtus neglectus Mello-Leitão, 1927) was recognized and redescribed, the difference between it and the other two species of the genus proved to be remarkable. Herein, a maximum parsimony phylogenetic analysis with morphological characters (2519 scorings; 28 taxa; 105 characters) was performed under equal and implied weights to test the monophyly of Paradiscocyrtus for the first time. According to the relatively stable results obtained, herein: 1) the transfer of Paradiscocyrtus cerayanus Roewer, 1929 to Discocyrtus Holmberg, 1878 (forming Discocyrtus cerayanus n. comb.) is proposed, and Paradiscocyrtus becomes monotypic (represented only by its type species); 2) the assignment of Paradiscocyrtus trochanteralis Roewer, 1929 (already detected as junior synonym of Bunopachylus orientalis (Roewer, 1913)) to Roeweriinae Carvalho & Kury, 2018 is corroborated; 3) the presence of Paradiscocyrtus in DRMN-group is detected and its relationship with Discocyrtus sensu stricto is discussed. Paradiscocyrtus can be separated from Discocyrtus s. str. by some external characters (as dorsal scutum gamma-type, a pair of finger-phalanx-shaped spines on the scutal area III and coxa IV retrolateral apophysis with the same length as the prolateral) and genital characters (as the stylus of glans slightly dorsally convex). Discocyrtus cerayanus n. comb. is herein redescribed, and its geographic distribution is contested. The meaning of “Ceraya”, assigned to the specimen SMF RII 996/53 (male holotype of Paradiscocyrtus cerayanus), is newly attributed to “Serra do Caraça”, a mountain range in Minas Gerais, Brazil instead of Northeastern Brazilian “Ceará”.

An unusual cryptogeobiid from southeastern Brazil revisited (Opiliones, Laniatores, Gonyleptoidea)

The monotypic genus Bunostigma Mello-Leitão, 1935 is herein revisited. A detailed redescription of its type-species, Bunostigma singulare Mello-Leitão, 1935 from Rio de Janeiro state, eastern Brazil, is herein presented, providing in depth knowledge of this genus. Bunostigma is most closely related to Cryptogeobius Mello-Leitão, 1935, and as this genus, it has a stout complex apophysis on male coxa IV, lacking, however, a second complex on the stigmatic area. Bunostigma has an oblique elongate malleus, similar to that of Zalanodius Mello-Leitão, 1936 (as opposed to a globular malleus in Cryptogeobius). Bunostigma singulare has short legs, with some sexual dimorphism on its stoutness, a dorsal scutum entirely unarmed and an ocularium with an accessory central mound, although unarmed.

A remarkable new species of Agoristenidae (Arachnida, Opiliones) from Córdoba, Colombia

A new species of Leiosteninae (Opiliones, Agoristenidae) from the Colombian Caribbean, Avima tuttifrutti sp. nov. García & Pastrana-M., is described and illustrated, based on two males from the montante forests of Tierralta (Córdoba department). The new species differs externally from other species of Avima by having one yellow hump on mesotergal area IV and green coloration on dorsal scutum. SEM images of the penis and a map showing its distribution are offered. This species represents the first record of a harvestman from the department of Córdoba and the eighth species of the subfamily recorded from the country.

Description and phylogenetic positioning of a new species of Heteropachylus Roewer, 1913 (Opiliones, Gonyleptidae, Heteropachylinae)

ABSTRACT Heteropachylus Roewer is the type genus of Heteropachylinae Kury, endemic to the Atlantic forest, Brazil. Heteropachyline males bear free tergites at least partially fused to dorsal scutum, besides other sexually dimorphic features common in gonyleptids as a higher ratio of maximum widths of abdominal scute and carapace and stronger armature of legs IV than females. We newly describe Heteropachylus thelydrias sp. nov. from Bahia, Brazil, in which males look like females regarding the shape of dorsal scute and armature of legs IV. Although the presence of polymorphic males is reported to this subfamily with morphs which may have variable sexually dimorphic features, our species appears to lack strongly developed males. Expanding on previous cladistic proposals, we investigated its phylogenetic positioning and found H. thelydrias sp. nov. as sister to a clade containing the remaining species of Heteropachylus (3 MPTs, 316 steps, CI 0.42, RI 0.60). The synapomorphies for Heteropachylus were armature of ocularium, the ectal armature of pedipalp tibia, calcaneus I lighter than astragalus, glans without digitiform dorsal process, and ventral plate with distal border distinctly concave. Although the branch support was low, we refrained from describing a new genus as it would not reflect the phylogenetic information we found. http://www.zoobank.org/urn:lsid:zoobank.org:pub:B707C01F-B905-4637-A6DF-7597B6C8FC13

Paragoniosomatinae, a new subfamily of Gonyleptidae (Arachnida: Opiliones), based on a new species from the Chapada Diamantina relict cloud forests, Brazil.

In this paper, we describe a new subfamily of Gonyleptidae, Paragoniosomatinae subfam. nov., based on a new genus and species, Paragoniosoma cachaceiro gen. nov., sp. nov., found in an upper montane cloud forest of Chapada Diamantina mountains, one of the small interior patches of Atlantic Forest. This discovery suggests that the narrow-restricted cloud forests are old relicts of an Atlantic Forest hotspot. Paragoniosoma cachaceiro gen. nov., sp. nov. is characterized by the presence of four areas on the dorsal scutum, serose dry mark in areas III-IV, seven basal setae in penis (macrosetae A and B) in two rows, and very large tarsal process. We performed a phylogenetic analysis based on morphological characters that revealed a close relationship of the new species with Goniosomatinae, a subfamily that includes six genera and 38 valid species distributed throughout the coastal Atlantic Forest. The new species also has the same habitat and other behavioural and ecological traits as Goniosomatinae, furnishing great insights on the evolution of their characteristic biology, e.g., subsocial behavior. Field surveys of harvestmen from the type locality and nearby lowland seasonal forests indicate a unique fauna, including additional new, undescribed species. In addition to phylogenetics, this dissimilarity with other regions and the presence of endemic species of other animal and plant taxa provide support for the consideration of the cloud montane patches of Chapada Diamantina as relicts. We discuss this rule in the historical biogeographic context of Atlantic Forest and suggest that the new species represents evidence of an Atlantic Forest that was more widespread in the past.

Two new Colombian harvestmen of the genus Quindina Roewer, 1914 (Opiliones: Nomoclastidae)

Two new Colombian species of Quindina Roewer, 1915 are here described based on genital morphology and external characters. Quindina hermesi sp. nov. (type locality: Bolívar, San Jacinto) can be diagnosed externally by having a combination of colored tubercles on the ocularium, the anterior margin, areas I, II and IV of the dorsal scutum, and the free tergites; Q. discolor sp. nov. (type locality: Magdalena, Ciénaga) shows a different combination of colored tubercles on the ocularium and lateral margins. Phylogenetic analyses were performed by adding both new species to an existing matrix for Nomoclastidae. The analyses resulted in various topologies for the relationships among Nomoclastes Sørensen, 1932, Napostygnus Roewer, 1929, Kichua Pinto-da-Rocha Bragagnolo, 2017, Callcosma Roewer, 1932 and Quindina Roewer, 1914, but all analyses recovered the monophyly of Callcosma and Quindina. This constitutes the first record of the family in northern Colombia.

Description of two new species of Progonyleptoidellus (Opiliones: Gonyleptidae),with a cladistic analysis of the genus, an overview of relationships in the K92 group, and taxonomic notes on Deltaspidium.

As part of an ongoing revision and cladistic analysis of the "K92 clade" (Gonyleptidae), the Brazilian genus Progonyleptoidellus Piza, 1940 is revised and two new species from São Paulo State are described: P. bocaina sp. nov. and P. picinguaba sp. nov. A cladistic analysis of the genus was performed using these two new species plus the three previously described species of the genus [P. fuscopictus (B. Soares, 1942); P. orguensis (Soares Soares, 1954); and P. striatus (Roewer, 1913)], and 25 more additional gonyleptoid outgroup species, most being representatives of the K92 clade. The data matrix is composed of 109 characters: three from the ocularium, 24 from the dorsal scutum, six from the free tergites, nine from the pedipalp, 41 from the legs and 26 from male genitalia. The genus Progonyleptoidellus was recovered as monophyletic only with the exclusion of P. orguensis and was supported on the basis of only one exclusive synapomorphy: presence of dry-marks on sulci of dorsal scutum. Based on the cladistic analysis, P. orguensis was reallocated in Deltaspidium Roewer, 1927, herein considered a senior synonym of Adhynastes Roewer, 1930, and two new combinations are proposed: Deltaspidium orguense (Soares Soares, 1954) and Deltaspidium tenue (Roewer, 1930). Diagnoses are given for Progonyleptoidellus, the previously described species, (P. fuscopictus and P. striatus) and the two new species.

Rediscovery of Eulibitia ectroxantha (Mello-Leitão, 1941) and synonymy of Sphalerocynorta Mello-Leitão, 1933 (Opiliones: Cosmetidae)

The species Brachylibitia ectroxantha was described by Mello-Leitão in 1941 and since then it was never again reported or studied. Its type is certainly lost and his identity was until now a mystery; it is currently considered as species inquirenda and transferred to Eulibitia in a recent revision of the genus. Herein, we designate a neotype and provide a redescription of the species based on fresh material from Belén (Boyacá, Colombia) 50km SW from the type locality, across the Chicamocha River. The species is recognizable by the blot pattern of the ladder mask of the dorsal scutum, the absence of groin warts in coxa IV and of armature in some areas of the mesotergum. Additional data about the genus is offered, and the species Cynortaambigua is herein recognized as a junior synonym of Eulibitia scalaris, involving the synonymy of the genus Sphalerocynorta Mello-Leitão, 1933.

A new species of Discocyrtoides from southern Brazilian pine forest (Opiliones, Gonyleptidae, Mitobatinae)

Discocyrtoidespinorum sp. nov. is described from the conifers forest in Paraná State, Southern Brazil. This is the second species of Discocyrtoides Mello-Leitão, 1923, the other being known from São Paulo State. It is remarkable for having greenish/yellowish spots in the dorsal scutum highly contrasting with the brown background, a feature rare in Mitobatinae, hitherto known only for Ruschia Mello-Leitão, 1940. It is the first record of this genus for Paraná State (WWF Ecoregion NT0101, Araucaria moist forests). Terminology for the male genitalia of the Mitobatinae is defined and illustrated.

A new species of Phonotimpus Gertsch Davis, 1940 (Araneae: Phrurolithidae) from Mexico.

The genus Phonotimpus Gertsch Davis, 1940 includes four species all known only from Mexico (World Spider Catalog 2018). P. separatus and P. eutypus were described by Gertsch Davis (1940) from San Luis Potosí and from Nuevo León, respectively. Phonotimpus pennimani and P. talquian, described by Chamé-Vázquez, Ibarra-Núñez Jiménez (2018), are the southernmost species in this genus (Chamé-Vázquez et al. 2018), and have restricted allopatric geographic distributions in Chiapas. This genus differs from other American phrurolithid genera by the following combination of characters: posterior eye row recurved, posterior median eyes closer to posterior lateral eyes than to each other, posterior median eyes smaller than posterior lateral eyes, females with dorsal scutum on the opisthosoma; palpi of males with retrolateral and dorsal tibial apophyses not joined at the base, and copulatory bulb with a conductor, embolus and embolar basal process (Gertsch Davis 1940; Penniman 1985; Chamé-Vázquez et al. 2018). In this paper, a new species of Phonotimpus is described and illustrated, based on specimens collected in soil of a pine-oak forest in the state of Mexico.

A whiter shade of pale: anchoring the name Paecilaema C. L. Koch, 1839 onto a neotype (Opiliones, Cosmetidae).

The generic name Paecilaema C.L. Koch, 1839 is anchored to the nomen dubium Cosmetus u-flavum Perty, 1833, and the fixation of the latter is proposed by designating a neotype. The choice was made on a potential topotype, being a common species in metropolitan Rio de Janeiro city, SE Brazil, which has been described as new five times and is currently best known as Metavononoides bellus (Mello-Leitão, 1932). Cosmetus u-flavum has been originally included in Paecilaema along with Paecilaema limbatum Kollar in C.L. Koch, 1839, the latter here synonymized with the former. Therefore, our choice of this species is adequate in conveying Koch's original concept of Paecilaema. The most striking diagnostic feature of the species of Paecilaema is the presence of a lyra, a unique shape of blots in layers of shades of white to pale yellow on the dorsal scutum. Other patterns of scutal white blots are hereby defined and named. Paecilaema is here considered most closely related to Metavononoides Roewer, 1928. Comments are made on the diagnostic characters and the terminology of parts of the lyra is expanded with the introduction of new terms. Comments are made on the formation of the generic name Paecilaema. Taxonomic adjustments are made in the closest relatives of Paecilaema u-flavum, and the following nomenclatural acts are proposed: (1) MNRJ 3433 is designated as male neotype of Cosmetus u-flavum, type species of Paecilaema. (2) Proposed new synonymies: Poecilaema soerenseni Henriksen, 1932 = Paecilaemula bella Mello-Leitão, 1932 = Eucynorta brasiliensis Mello-Leitão, 1923 = Paecilaema limbatum Kollar in C.L. Koch, 1839 = Cosmetus u-flavum Perty, 1833. (3) Nine species originally described elsewhere but currently placed in Metavononoides are transferred to Paecilaema, either as new or as restored combinations: Paecilaemula albisecta Mello-Leitão, 1942, Poecilaemula albosigillata Mello-Leitão, 1941, Paecilaema lyra Sørensen, 1932, Metavononoides melanacanthus Ferreira, Pedroso Kury, 2005, Paecilaema muticum Sørensen, 1932, Paecilaema ornatissimum Mello-Leitão 1942, Poecilaemula peculiare Roewer, 1917, Paecilaemula preciosa Roewer 1928 and Metavononoides renneri Ferreira, Pedroso Kury, 2007. (4) The following genera, currently in the synonymy of Paecilaema, are all revalidated and given emended diagnoses: Meterginoides Roewer, 1912, Meterginulus Roewer, 1912, Paecilaemella Roewer, 1925, Pararhauculus Roewer, 1933, Soaresella Goodnight Goodnight 1947. (5) Their respective type species, currently combined under Paecilaema, are transferred back to their revalidated genera: Paecilaema rastelliferum Pickard-Cambridge 1905 to Meterginulus; Meterginus inermis Banks, 1909 to Meterginoides; Pararhauculus lineatus Roewer, 1933 to Pararhauculus; Paecilaemella festae Roewer, 1925 to Paecilaemella and Soaresella gracilis Goodnight Goodnight, 1947 to Soaresella.

Description of a new species of Eucynorta (Opiliones, Cosmetidae) from Cortés, Honduras.

A new species, Eucynorta rooneyi sp. nov. (Opiliones, Cosmetidae), is described from Parque Nacional Cusuco, Cortés, Honduras, a tropical montane cloud forest habitat. This is the thirty-fifth species of Eucynorta Roewer, 1912, and is characterized by the combination of three sexually dimorphic characters in males: enlarged chelicerae, some armature on femur III and IV, and swollen basitarsi on leg I. This new species is distinct from other Eucynorta species due to its unique pattern of yellow markings on area I of the dorsal scutum, and unarmed free tergites with line markings.

Do the species with facies reclinobunoides make up a clade?-A new Lomanius (Opiliones, Podoctidae) from Vietnam and a discussion on its relationships.

Lomanius annae sp. nov. is described from southern Vietnam. The species is characterized by the greatly developed dorso-basal process on cheliceral hand of males and by the partial effacement of all mesotergal grooves. The genus Lomanius contains four generic synonyms and currently comprises eight valid species distributed in China, Java, peninsular Malaysia, the Philippines, and Taiwan. The new species displays a general morphology similar to the former genus Paralomanius, with a combination of sexually dimorphic interocular mound (which is very large and strongly leaned back in males) and pedipalpus (which is extremely elongate in males). This morphological suite of features is herein called facies reclinobunoides. The replacement name Metibalonius triceratops nom. nov. is proposed for Trispinibunus abnormis Roewer, 1915, which is a junior secondary homonym of Ibalonius abnormis Strand, 1911. Finally, numerous morphological structures found in Podoctidae are recognized and named: (1) the cheliceral comb, present on cheliceral fingers, (2) the chained tubercular ridges, present on dorsal scutum and (3) several others related to the ocular region. The distribution of these two structures among podoctid species is not fully known, but both are absent in the former Ibaloniinae. We suggest that both structures may be useful to define supra-generic groups in the clade composed of the former Podoctinae and Erecananinae.

Redescription of Paradiscocyrtus neglectus Mello-Leitão, 1927 (Opiliones: Gonyleptidae), with the designation of a neotype and two synonymies

Paradiscocyrtus neglectus Mello-Leitão, 1927 is here redescribed and for the first time illustrated. A neotype is proposed to clarify the taxonomic status of this species and to differentiate it from the other two species of Paradiscocyrtus and related genera (e.g., Discocyrtus). Two junior synonyms of this species, currently allocated in Discocyrtus Holmberg, 1876 are here detected. This harvestman is endemic from areas above 2000 meters of altitude, occurring in the Campos Rupestres montane savannas terrestrial eco-region in the states of Minas Gerais and Rio de Janeiro, Brazil. This species is characterized by the powerful retrodorsal apophysis of the coxa IV, the unique armature of dorsal scutum, trochanter IV, and femur IV.

Further dismemberment of Discocyrtus with description of a new Amazonian genus and a new subfamily of Gonyleptidae (Opiliones, Laniatores)

A group of Amazonian harvestmen is recognized and described as Amazochroma gen. nov. This taxon includes Discocyrtus carvalhoi Mello-Leitão, 1941 (type species), the only species of Discocyrtus previously thought to occur in Amazonia, and Amazochroma pedroi gen. et sp. nov., described here from the Brazilian states of Acre and Rondônia. New records are added for Amazochroma carvalhoi gen. et comb. nov, expanding its distribution from the Brazilian state of Mato Grosso northwards also to Pará and Amazonas in Brazil and additionally French Guiana and Suriname. Diagnostic features of Amazochroma gen. nov. include: trichromatic pattern of legs, dry marks on the dorsal scutum and base of legs and diastema in the row of macrosetae C of the penis ventral plate. A morphological maximum parsimony analysis (1022 scorings; 16 taxa; 64 characters) is performed to test whether Amazochroma gen. nov. is a member of Discocyrtus and if the traditional allocation of Discocyrtus in Pachylinae is defendable. A clade is retrieved containing three groups: (1) Mitobatinae, (2) Discocyrtus and (3) a clade containing Amazochroma gen. nov., Discocyrtanus and Roeweria, here described as a new subfamily of Gonyleptidae – Roeweriinae subfam. nov. Discocyrtanus Roewer, 1929 and Roeweria Mello-Leitão, 1923 are accordingly here transferred from Pachylinae to Roeweriinae subfam. nov.