Measuring the heart rate of the spider, Aphonopelma hentzi: a non-invasive technique

In this work we describe a non‐invasive and precise technique to record the heartbeats of a spider. A linear output Hall effect transducer in conjunction with a small magnet was used to monitor the micromovements on the dorsal surface of the abdomen of the tarantula Aphonopelma hentzi (Girard) (Theraphosidae). The exoskeleton in this region is in direct contact with suspensory ligaments connected to the heart, and the dorsal cuticle of the opisthosoma moves with each heartbeat. The technique allowed the discrimination of the different stages of the spider's cardiac cycle. The method can be also adapted for a smaller spider or other arthropods. We believe that the method proposed in this paper allows investigators to gain insights into a spider's natural heart rate by gathering unbiased data with a non‐invasive and very precise technique. We have found the resting heart rate of A. hentzi to be 5.6 ± 1.47 beats/min, which is lower than previously reported values.     

Species delimitation and phylogeography of Aphonopelma hentzi (Araneae, Mygalomorphae, Theraphosidae): cryptic diversity in North American tarantulas

Background

The primary objective of this study is to reconstruct the phylogeny of the hentzi species group and sister species in the North American tarantula genus, Aphonopelma, using a set of mitochondrial DNA markers that include the animal “barcoding gene”. An mtDNA genealogy is used to consider questions regarding species boundary delimitation and to evaluate timing of divergence to infer historical biogeographic events that played a role in shaping the present-day diversity and distribution. We aimed to identify potential refugial locations, directionality of range expansion, and test whether A. hentzi post-glacial expansion fit a predicted time frame.

Methods and Findings

A Bayesian phylogenetic approach was used to analyze a 2051 base pair (bp) mtDNA data matrix comprising aligned fragments of the gene regions CO1 (1165 bp) and ND1-16S (886 bp). Multiple species delimitation techniques (DNA tree-based methods, a “barcode gap” using percent of pairwise sequence divergence (uncorrected p-distances), and the GMYC method) consistently recognized a number of divergent and genealogically exclusive groups.

Conclusions

The use of numerous species delimitation methods, in concert, provide an effective approach to dissecting species boundaries in this spider group; as well they seem to provide strong evidence for a number of nominal, previously undiscovered, and cryptic species. Our data also indicate that Pleistocene habitat fragmentation and subsequent range expansion events may have shaped contemporary phylogeographic patterns of Aphonopelma diversity in the southwestern United States, particularly for the A. hentzi species group. These findings indicate that future species delimitation approaches need to be analyzed in context of a number of factors, such as the sampling distribution, loci used, biogeographic history, breadth of morphological variation, ecological factors, and behavioral data, to make truly integrative decisions about what constitutes an evolutionary lineage recognized as a “species”.     

我国南方近捕鸟蛛属一新种(蜘蛛目:捕鸟蛛科)

记述了我国南方近捕鸟蛛属一新种,定各为广西近捕鸟蛛,新种Ｐｌｅｓｉｏｐｈｒｉｃｔｕｓ ｇｕａｎｇｘｉｅｎｓｉｓ ｓｐ．ｎｏｖ．。     

A new species of the genus Chaetopelma Ausserer, 1871 (Araneae: Theraphosidae) from Turkey

A new species of Chaetopelma Ausserer, 1871 is described from Hatay province, Turkey. Differences between the new species and related species are discussed. The characteristic features of this species are described and illustrated.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:99C21605-5308-4363-8420-02F6151B4457     

渡濑雅美蛛的再描述及分类研究(蜘蛛目:狒蛛科)

本文重新描述和图示了产于台湾兰屿的渡濑雅美蛛Yamia watasei Kishida 1920.由于颚叶无发声器,认为本种不属于棒刺蛛亚科Selenocosmoinae,应暂放在雅美蛛亚科Yamiinae.标本保存在河北大学生命科学学院.     

Energy metabolism and the postprandial response of the Chilean tarantulas, Euathlus truculentus (Araneae: Theraphosidae)

One of the most ubiquitous consequences of feeding in animals is specific dynamic action (SDA), a drastic increment in metabolic rate after a meal, which lasts from a few hours to several days. According to a recent exhaustive review by Secor (2009), studies in SDA are abundant, encompassing all kinds of vertebrates and invertebrates. However, important exceptions are arachnids, as few studies have characterized SDA in this group. Here, we measured the standard metabolic rate (SMR) of the Chilean tarantulas Euathlus truculentus (body mass=7.32±0.7 g; N=32; T(A)=25°C), its inter-individual variation (i.e., repeatability) and its SDA. We measured SMR three or four times in each individual, and we also conducted predation experiments where a prey was consumed by each spider, during a respirometry trial. The SMR of E. truculentus was 0.00049±0.000079 mlCO(2) g(-1) min(-1) which corresponds to 1524 μW (assuming a protein-based diet), 108.4% of the predicted value for arachnids. According to the standard nomenclature for SDA studies, the scope of the SDA for a meal size of 1.26±0.04 g (18% of the spider size) was 6.55±1.1 times the baseline, the time to peak was 45 min, and the magnitude of the SDA was 0.28±0.03 kj, which is 85% of the expected value for invertebrates. Our SMR data are in concordance with previous findings suggesting remarkably low energy metabolism in arachnids, compared with other arthropods. On the other hand, the exceedingly high scope of the postprandial response contrasts with the comparatively low SDA. This fact suggests that spiders spend most of the energy for digestion in a short period after prey capture, which could be a consequence of their external digestion.     

Morphology and ultrastructure of the Malpighian tubules of the Chilean common tarantula (Araneae: Theraphosidae).

Relatively little is known about the morphology and ultrastructure of the Malpighian tubules of spiders (Arachnida: Araneae). Our study represents the first investigation of the Malpighian tubules of a theraphosid spider and is the only study to examine the living Malpighian tubules using confocal laser scanning microscopy. In theraphosid spiders, the Malpighian tubules originate from the stercoral pocket in the posterior portion of the opisthosoma and extend forward toward the prosoma in a dendritic pattern. There are three distinct segments (initial, main, and terminal), all dark brown in appearance. Each segment has distinctive ultrastructural features. Both the terminal and the main segment appear to be composed of at least two cell types with finger-like cytoplasmic protrusions associated with one of these types. The terminal segment, which is most proximal to the stercoral pocket, is the largest in diameter. It is composed of large, cuboidal cells containing many mitochondria and lipid inclusions. The main segment is intermediate in diameter with many mitochondria and secretory vesicles present. The initial segment is relatively thin in comparison to the other segments and is intimately associated with the digestive gland. The cells of the initial segment contain very little cytoplasm, fewer mitochondria, secretory vesicles, and prominent inclusions.     

Spatial distribution and habitat preference of the endangered tarantula, Brachypelma klaasi (Araneae: Theraphosidae) in Mexico

Brachypelma, a genus of nine endangered tarantula species in Mexico, is the only group of spiders included in Appendix II of CITES, owing to habitat degradation and illegal trafficking. However, while the majority of the nine species of Brachypelma are thought to be threatened, little is known of their ecology and distribution. Brachypelma klaasi is the rarest species, occurring in a few isolated populations on the Pacific coast of Mexico. We present an analysis of population distribution and micro-habitat requirements of B. klaasi over different spatial scales within the biological reserve at Chamela, Jalisco as part of a wider ecological study of the endangered Brachypelma group. Burrows and dispersing spiders were confined to a southern area of the reserve covering approximately 0.5 km². Within this area, burrows were not aggregated at lower spatial scales (2⁴–2¹⁶ m²), unlike other related species. Also, there was no evidence that intra-specific interactions (either positive or negative interactions) influenced the distribution of burrows. Distribution of burrows at low spatial scales was related to low afternoon temperatures and high humidity in mid-summer. These abiotic factors may influence the survival and development of eggs and spiderlings, and appear to be more important in governing the distribution of B. klaasi than are food resources or intra-specific interactions. We discuss how these findings may facilitate the re-introduction of captive-bred individuals of B. klaasi and other Brachypelma species.     

Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae,Mygalomorphae, Theraphosidae) within the United States

This systematic study documents the taxonomy, diversity, and distribution of the tarantula spider genus Aphonopelma Pocock, 1901 within the United States. By employing phylogenomic, morphological, and geospatial data, we evaluated all 55 nominal species in the United States to examine the evolutionary history of Aphonopelma and the group’s taxonomy by implementing an integrative approach to species delimitation. Based on our analyses, we now recognize only 29 distinct species in the United States. We propose 33 new synonymies (Aphonopelma apacheum, Aphonopelma minchi, Aphonopelma rothi, Aphonopelma schmidti, Aphonopelma stahnkei = Aphonopelma chalcodes; Aphonopelma arnoldi = Aphonopelma armada; Aphonopelma behlei, Aphonopelma vogelae = Aphonopelma marxi; Aphonopelma breenei = Aphonopelma anax; Aphonopelma chambersi, Aphonopelma clarum, Aphonopelma cryptethum, Aphonopelma sandersoni, Aphonopelma sullivani = Aphonopelma eutylenum; Aphonopelma clarki, Aphonopelma coloradanum, Aphonopelma echinum, Aphonopelma gurleyi, Aphonopelma harlingenum, Aphonopelma odelli, Aphonopelma waconum, Aphonopelma wichitanum = Aphonopelma hentzi; Aphonopelma heterops = Aphonopelma moderatum; Aphonopelma jungi, Aphonopelma punzoi = Aphonopelma vorhiesi; Aphonopelma brunnius, Aphonopelma chamberlini, Aphonopelma iviei, Aphonopelma lithodomum, Aphonopelma smithi, Aphonopelma zionis = Aphonopelma iodius; Aphonopelma phanum, Aphonopelma reversum = Aphonopelma steindachneri), 14 new species (Aphonopelma atomicum sp. n., Aphonopelma catalina sp. n., Aphonopelma chiricahua sp. n., Aphonopelma icenoglei sp. n., Aphonopelma johnnycashi sp. n., Aphonopelma madera sp. n., Aphonopelma mareki sp. n., Aphonopelma moellendorfi sp. n., Aphonopelma parvum sp. n., Aphonopelma peloncillo sp. n., Aphonopelma prenticei sp. n., Aphonopelma saguaro sp. n., Aphonopelma superstitionense sp. n., and Aphonopelma xwalxwal sp. n.), and seven nomina dubia (Aphonopelma baergi, Aphonopelma cratium, Aphonopelma hollyi, Aphonopelma mordax, Aphonopelma radinum, Aphonopelma rusticum, Aphonopelma texense). Our proposed species tree based on Anchored Enrichment data delimits five major lineages: a monotypic group confined to California, a western group, an eastern group, a group primarily distributed in high-elevation areas, and a group that comprises several miniaturized species. Multiple species are distributed throughout two biodiversity hotspots in the United States (i.e., California Floristic Province and Madrean Pine-Oak Woodlands). Keys are provided for identification of both males and females. By conducting the most comprehensive sampling of a single theraphosid genus to date, this research significantly broadens the scope of prior molecular and morphological investigations, finally bringing a modern understanding of species delimitation in this dynamic and charismatic group of spiders.     

Impact of disturbed areas on Theraphosidae spiders diversity (Araneae) and first population data of Grammostola rosea (Walckenaer) in Panul Park

Soil fauna constitutes one of the most abundant and richest environments on earth (Coleman et al. 2004, Fundamentals of solil ecology, 2nd ed. Elsevier Academic Press, London, UK). Different degrees of soil disturbance can affect arthropod diversity, which allows a correlation of biodiversity to quality of habitat. The present study aimed to evaluate the impact of habitat on Theraphosidae spiders, with special focus on Grammostola rosea. Slight differences in the diversity of Theraphosidae between the disturbed area of Cerro Huechuraba and the undisturbed Panul Park were found. However, a high dominance of G. rosea was observed in both study areas. G. rosea density 1,350 ind/ha in Panul Park, and 750 ind/ha in Cerro Huechuraba. UPGMA cluster analysis did not show significant differences between established environments. A standard methodology to develop inventories of Theraphosidae was proposed. The distribution of G. rosea and its natural history were reported.     

Theraphosidae phylogeny: relationships of the ‘Ischnocolinae’ genera (Araneae,Mygalomorphae)

The mygalomorph spider subfamily ‘Ischnocolinae’ was originally established as a group based on the presence of divided tarsal scopula. Later, the divided condition of the scopula was considered the plesiomorphic state, which could not support the monophyly of ‘Ischnocolinae’. In Raven 1985, the subfamily was considered paraphyletic, pending a phylogenetic analysis to reinvestigate monophyletic groups. This study comprises such a phylogenetic analysis, based on morphological data, that includes representatives of all genera currently included in ‘Ischnocolinae’ as well as representatives of all other nine Theraphosidae subfamilies (Thrigmopoeinae, Ornithoctoninae, Eumenophorinae, Stromatopelminae, Harpactirinae, Selenogyrinae, Theraphosinae, Aviculariinae and Selenocosmiinae). The family Theraphosidae is considered monophyletic and expanded to include three additional genera previously considered as possible Barychelidae, namely Brachionopus (as Harpactirinae), Trichopelma and Reichlingia (as Ischnocolinae sensu stricto) while ‘Ischnocolinae’ as previously defined does not appear as monophyletic. However, two monophyletic groups were defined as subfamilies to include some former ‘Ischnocolinae’ representatives. The first group includes Acanthopelma rufescens, Trichopelma nitidum, Reichlingia annae, Ischnocolus spp., Holothele rondoni, Holothele culebrae and Holothele aff culebrae and is hereby named as Ischnocolinae (sensu stricto). The other subgroup comprises Sickius longibulbi, Holothele incei, Holothele aff incei, Guyruita spp., Schismatothele lineata, Hemiercus modestus, Holothele colonica and Holothele sp., together established as Schismatothelinae subfam. nov. Several genera included in former ‘Ischnocolinae’ appear as monophyletic (Catumiri, Oligoxystre, Heterothele, Nesiergus, Chaetopelma, Ischnocolus, Guyruita and Plesiophrictus). However, the genera Holothele, Schismatothele and Hemiercus deserve more attention in order to evaluate their intrarelationships and inclusion of species.     

Agonistic interactions, cuticular and hemolymphatic lipid variations during the foraging period in spider females Brachypelma albopilosa (Theraphosidae)

Agonistic behaviour and lipid state were examined in tarantula Brachypelma albopilosa females during the foraging period. Modulation of the agonistic behaviour of females was not connected to their body size. Results show that the agonistic pattern of females differed significantly from the predation pattern at the behavioural and lipid levels. Aggressive-foraging females had low predation behaviour. Quantitative lipid changes were observed in relation to agonistic behaviour and predation. The total lipid index was studied by colorimetric methods, and lipid compounds were analyzed by gas chromatography-mass spectrometry in cuticle and hemolymph of females. The lipid components were free fatty acids, methyl esters, cholesterol, and long-chain aliphatic hydrocarbons. Methyl esters were much more abundant in cuticular lipids; unsaturated free fatty acids (linoleic and oleic acids) and methyl esters (methyl linoleate and methyl stearate) predominated in the hemolymph. Spider aggression was positively correlated with lipid concentration (cholesterol, fatty acids, methyl esters and hydrocarbons) in the hemolymph and the levels of cuticular fatty acids. Lipid levels are hypothesized to have evolved as a regulatory factor of predation and agonistic behaviours in tarantula females.     

Resolving the unresolved tribe: a molecular phylogenetic framework for the Merremieae (Convolvulaceae)

Tribe Merremieae, as currently circumscribed, comprise c. 120 species classified in seven genera, the largest of which (Merremia) is morphologically heterogeneous. Previous studies, with limited sampling, have suggested that neither Merremieae nor Merremia are monophyletic. In the present study, the monophyly of Merremia and its allied genera was re‐assessed, sampling 57 species of Merremieae for the plastid matK, trnL–trnF and rps16 regions and the nuclear internal transcribed spacer (ITS) region. All genera of Merremieae and all major morphotypes in Merremia were represented. Phylogenetic analyses resolve Merremieae in a clade with Ipomoeae, Convolvuleae and Daustinia montana. Merremia is confirmed as polyphyletic and a number of well‐supported and morphologically distinct clades in Merremieae are recognized which accommodate most of the species in the tribe. These provide a framework for a generic revision of the assemblage. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015.     

Review of Erigonine spider genera in the Neotropics (Araneae: Linyphiidae,Erigoninae)

The Neotropical genera of the linyphiid spider subfamily Erigoninae are revised at the genus level. Emphasis was placed on genera endemic to the Neotropics and species with dubious relationships to their nominal genera, especially species from the older literature. This work recognizes 50 genera in the Neotropics, of which 39 genera are strictly endemic to the Neotropics, three are represented outside the Neotropics by one species, and eight genera have significant representation both in and beyond the Neotropics. Three additional genera, Ceraticelus Simon, 1884, Idionella Banks, 1893, and Eulaira Chamberlin & Ivie, 1933, are represented in northern Mexico and/or the West Indies, but are best classified as having a Nearctic or Holarctic distribution. Species previously placed in the typically northern hemisphere genera Gongylidiellum Simon, 1884, Leptorhoptrum Kulczynski, 1894, Macrargus Dahl, 1886, Minyriolus Simon, 1884, Oedothorax Bertkau, 1883, Phanetta Keyserling, 1886, and Tmeticus Menge, 1868 are found to be misplaced or nomina dubia; two genera endemic to the Neotropics, Clitistes Simon, 1902 and Zilephus Simon, 1902 are nomina dubia. The genus Beauchenia Usher, 1983 is an erigonine, not a mynoglenine; there are no known representatives of the Mynogleninae in the Neotropics. One hundred and forty new combinations are established; 19 genera are synonymized including Micromaso Tambs‐Lyche, 1954, revalidation rejected; 34 species are synonymized. The following new genera are established: Gigapassus gen. nov. , Intecymbium gen. nov. , Moyosi gen. nov. , Orfeo gen. nov. and Toltecaria gen. nov. Malkinella Millidge, 1991 and Valdiviella Millidge, 1985 are preoccupied; Malkinola nom. nov. and Valdiviola nom. nov. are established as replacement names. The following new species are described: Asemostera daedalus sp. nov. , Asemostera enkidu sp. nov. , Asemostera janetae sp. nov. , Fissiscapus attercop sp. nov. , Gonatoraphis lysistrata sp. nov. , Gravipalpus standifer sp. nov. , Microplanus odin sp. nov. , Moyosi chumota sp. nov. , Myrmecomelix leucippus sp. nov. , Neomaso damocles sp. nov. , Notiomaso exonychus sp. nov. , Paraletes pogo sp. nov. , Psilocymbium acanthodes sp. nov. , Smermisia holdridgi sp. nov. and Smermisia parvoris sp. nov. The following species remain misplaced in inappropriate genera: Erigone fellita Keyserling, 1886, Erigone zabluta Keyserling, 1886, and Oedothorax fuegianus (Simon, 1902). For 23 species, type specimens could not be located and the species could not be unambiguously identified; the type of Macrargus pacificus Berland, 1924 could not be located, but it is transferred to Laminacauda Millidge, 1985. The female of Onychembolus subalpinus Millidge, 1985 described by Millidge in 1991 is mismatched; this female is Notiomaso exonychus sp. nov. ; the true female of Onychembolus subalpinus was described as both Neomaso bidentatus Millidge, 1991 syn. nov. and Neomaso tridentatus Millidge, 1991 syn. nov. The male and female of Asemonetes[now Asemostera]arcana (Millidge, 1991) are not conspecific; a male thought to be conspecific with the female of A. arcana is newly described; the true female of A. arcana is unknown. The transfer of Emenista dentichelis Berland, 1913 to Laminacauda comb. nov. renders Laminacauda dentichelis Millidge, 1991 a junior homonym; the replacement name Laminacauda baerti nom. nov. is provided for Laminacauda dentichelis Millidge. The following species were erroneously placed in erigonine genera: Oedothorax bisignatus Mello‐Leitão, 1945 is synonymized with Theridion calcynatum Holmberg, 1876 syn. nov. (Theridiidae); Liger incomta O. Pickard‐Cambridge, 1896 is transferred to Theridion Walckenaer, 1805 (Theridiidae) [Theridion incomtum comb. nov. ]; Erigone ectrapela Keyserling, 1886 is transferred to Dictyna Sundevall, 1833 (Dictynidae) [Dictyna ectrapela comb. nov. ]; Erigone peruana Keyserling, 1886 is transferred to Thymoites Keyserling, 1884 (Theridiidae) [Thymoites peruanus comb. nov. ]; Adelonetria dubiosa Millidge, 1991 is not a linyphiid and will be dealt with elsewhere. Lomaita darlingtoni Bryant, 1948 is confirmed as a linyphiid, not a mysmenid. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149 (Suppl. 1), 1–263.     

Systematics of the spider genera Mallos and Mexitlia (Araneae, Dictynidae)

This systematic study recognizes and describes 14 species of the genus Mallos O. Pickard-Cambridge, 1902 and three species of the genus Mexitlia Lehtinen, 1967. Three species of Mallos – Mallos gertschi, Mallos chamberlini and Mallos macrolirus –and one species of Mexitlia – Mexitlia altima –are newly described. Mallos ghiggi (Caporiacco, 1938) is considered a synonym of Mexitlia grandis (O. Pickard-Cambridge, 1896). Mexitlia grandis is considered the senior synonym of Mexitlia avara (Banks, 1898). Two species, Mallos jlavovittatus (Keyserling, 1880) and Mallos nigrescens (Caporiacco, 1955) are removed from Mallos. The males of Mallos kraussi Gertsch, 1946 and Mallos blandus Chamberlin and Gertsch 1958, are described for the first time. A cladistic analysis based on 26 morphological characters produced a cladogram that supports the monophyly of Mallos and the validity of Mexitlia. This cladogram presents a phylogenetic framework for considering the evolution of social behaviour in Mallos.