Two new species of harvestmen (Opiliones,Eupnoi, Neopilionidae) from Waitomo,New Zealand

Two new species of harvestman (Opiliones: Neopilionidae: Enantiobuninae) are described from the Waitomo region of the North Island, New Zealand, Forsteropsalis bona sp. n. and F. photophaga sp. n. Both have been collected within caves in the region, where predation on glow-worms Arachnocampa luminosa has been previously recorded for one or both species (misidentified as ‘Megalopsalis tumida’). However, both are regarded as troglophiles rather than strict troglobites due to the presence of specimens outside the cave systems, and the absence of troglobitic adaptations. Megalopsalis tumida (Forster, 1944) is identified as a junior synonym of Forsteropsalis fabulosa (Phillipps & Grimmett, 1932).     

Steinernema diaprepesi n. sp. (Rhabditida: Steinernematidae), a Parasite of the Citrus Root Weevil Diaprepes abbreviatus (L) (Coleoptera: Curculionidae)

A nematode collected from Diaprepes abbreviatus is identified and described as a new species, Steinernema diaprepesi n. sp. The new species is closely related to S. feltiae, S. glaseri, and S. oregonense and can be distinguished from these species by the following characteristics: Males: Spicule averaging 79 (71-90) µm and spicule shape; D% (distance from anterior end to excretory pore/ esophagus length × 100) about 80; the ratio SW (spicule length/anal body width) about 1.8. Females: Vulva with short, double- flapped epiptygma; tail terminus usually with 5 papillae-like structures. Infective juveniles: Body averaging 1,002 (880-1,133) µm, EP (distance from anterior end to excretory pore) = 74 (66-83) µm; tail length = 83 (65-91) µm, and E% (EP/tail length × 100) = 89.6 (78-114). Lateral field pattern variable, the formula for the arrangement of ridges from head to tail is: 2, 6, 7, 8, 4, 2. The portion with eight ridges is the longest. This new species can be differentiated further from three closest species (S. feltiae, S. glaseri, and S. oregonense) by characteristic sequences of their ITS regions, including sequence lengths, ratios of similarity, composition, and differences in base characters in sequence alignment.     

Macrogenomic Evidence for the Origin of the Black Fly Simulium suzukii (Diptera: Simuliidae) on Okinawa Island,Japan

To determine the geographic origin of the black fly Simulium suzukii on Okinawa Island, Japan, macrogenomic profiles derived from its polytene chromosomes were compared with those of mainland and other insular populations of S. suzukii and of the isomorphic Simulium tani species complex. The Okinawan population is a chromosomally unique cytoform, designated ‘D,’ which is essentially monomorphic and differs by about 27 fixed rearrangements from the chromosomal standard sequence for the subgenus Simulium and by two fixed differences from its nearest known relative, representing the type of S. suzukii, on the main islands of Japan. Chromosomal band sequences revealed two additional, sympatric cytoforms of S. suzukii, designated ‘A’ and ‘B,’ each with species status, in Korea, and a third cytoform, designated ‘C,’ on Hokkaido, Japan. A new cytoform, ‘K,’ of S. tani from Malaysia, representing the type of S. tani, is more closely related to cytoforms in Thailand, as are populations from Taiwan previously treated as S. suzukii but more closely aligned with S. tani and newly recognized as cytoform ‘L’ of the latter nominal species. Rooting of chromosomal band sequences by outgroup comparisons allowed directionality of chromosomal rearrangements to be established, enabling phylogenetic inference of cytoforms. Of 41 macrogenomic rearrangements discovered in the five new cytoforms, four provide evidence for a stepwise origin of the Okinawan population from populations characteristic of the main islands of Japan. The macrogenomic approach applied to black flies on Okinawa Island illustrates its potential utility in defining source areas for other species of flies including those that might pose medical and veterinary risks.     

Review of the species level taxonomy of the neotropical butterfly genus Oenomaus (Lycaenidae,?Theclinae,?Eumaeini)

Seven new species of the Neotropical hairstreak genus Oenomaus are described: Oenomaus mancha Busby & Faynel, sp. n. (type locality Ecuador); Oenomaus gwenish Robbins & Faynel, sp. n. (type locality Panama); Oenomaus lea Faynel & Robbins, sp. n. (type locality Ecuador); Oenomaus myrteana Busby, Robbins & Faynel, sp. n. (type locality Ecuador); Oenomaus mentirosa Faynel & Robbins, sp. n. (type locality Peru); Oenomaus andi Busby & Faynel, sp. n. (type locality Ecuador) and Oenomaus moseri Robbins & Faynel, sp. n. (type locality Brazil, Santa Catarina). For each new Oenomaus species, we present diagnostic characters and notes on its habitat and biology. We illustrate adults, genitalia, and distribution. New distributional and biological data are presented for 21 previously described Oenomaus species. Oenomaus melleus guyanensis Faynel, 2008 is treated as a new synonym of Oenomaus melleus melleus (Druce, 1907). Females are described and associated with males for ten species using a variety of factors, including mitochondrial COI DNA “barcode” sequences. We summarize the reasons why the number of recognized Oenomaus species has grown in the past decade from one species to 28 species. Finally, we overview the habitats that Oenomaus species occupy and note that the agricultural pest on Annonaceae, Oenomaus ortygnus, is the only Oenomaus species that regularly occurs in greatly disturbed habitats.     

Review of the genus Fontidessus Miller & Spangler, 2008 (Coleoptera,Dytiscidae, Hydroporinae,Bidessini) with description of four new species

The genus Fontidessus Miller & Spangler, 2008 (Coleoptera: Dytiscidae: Hydroporinae: Bidessini) is reviewed. The genus now includes seven species with three previously described, and four new species described here: F. microphthalmus Miller & Montano, sp. n.; F. bettae Miller & Montano, sp. n.; F. christineae Miller & Montano, sp. n., and F. aquarupe Miller & Montano, sp. n. Each species is diagnosed and described, including the previously known species, based on new specimens and new information. Habitus, male genitalia and other diagnostic features are illustrated for each species. A key to the seven species is provided. Fontidessus species are unique to hygropetric habitats in the Guiana Shield craton of northern South American.     

Revision of the East Mediterranean Orthomus (Coleoptera,Carabidae, Pterostichini), with description of Parorthomus gen. n. socotranus sp. n. from Socotra Island and key to the Old World genera of subtribe Euchroina

The East Mediterranean species of Orthomus Chaudoir, 1838 are revised. The type series of Feronia longula Reiche & Saulcy, 1855, F. berytensis Reiche & Saulcy, 1855, F. proelonga Reiche & Saulcy, 1855, Orthomus longior Chaudoir, 1873, O. sidonicus Chaudoir, 1873, and O. berytensis akbensis Mateu, 1955 were studied and lectotypes for the first four are designated. Also, the following nomenclatural acts are proposed: Feronia proelonga Reiche & Saulcy, 1855, syn. n. of Orthomus berytensis (Reiche & Saulcy, 1855); Feronia elongata Chaudoir, 1859, syn. n. of Orthomus berytensis (Reiche & Saulcy, 1855); Orthomus sidonicus Chaudoir, 1873, syn. n. of Orthomus longior Chaudoir, 1873; Orthomus velocissimus andalusiacus Mateu, 1957, syn. n. of Orthomus velocissimus akbensis Mateu, 1955, new assignment for Orthomus berytensis akbensis Mateu, 1955. As a result, three species of the genus inhabit the East Mediterranean biogeographical region: O. berytensis, O. longior, and O. longulus. A key to these three species is given. O. longior is recorded for Turkey and Syria for the first time. In addition, a new synonymy of two West Mediterranean taxa is proposed: O. szekessyi (Jedlička, 1956), syn. n. of O. balearicus (Piochard de la Brûlerie, 1868), and a new genus and a species are described: Parorthomus gen. n. socotranus sp. n. (type locality: Republic of Yemen, Socotra Archipelago, Socotra Island, Fimihin env., 530 m.a.s.l.). Illustrations of the species dealt with here are provided including external characters, habitus, mentum and submentum, and genitalia are provided.Nine genera of the “African Series” of subtribe Euchroina Chaudoir, 1874 are keyed for the first time. Checklists of the species of Orthomus and of the Old World euchroine genera are given.     

A new Liopropoma sea bass (Serranidae,Epinephelinae, Liopropomini) from deep reefs off Cura?ao,southern Caribbean,with comments on depth distributions of western Atlantic liopropomins

Collecting reef-fish specimens using a manned submersible diving to 300 m off Curaçao, southern Caribbean, is resulting in the discovery of numerous new fish species. The new Liopropoma sea bass described here differs from other western Atlantic members of the genus in having VIII, 13 dorsal-fin rays; a moderately indented dorsal-fin margin; a yellow-orange stripe along the entire upper lip; a series of approximately 13 white, chevron-shaped markings on the ventral portion of the trunk; and a reddish-black blotch on the tip of the lower caudal-fin lobe. The new species, with predominantly yellow body and fins, closely resembles the other two “golden basses” found together with it at Curaçao: L. aberrans and L. olneyi. It also shares morphological features with the other western Atlantic liopropomin genus, Bathyanthias. Preliminary phylogenetic data suggest that western Atlantic liopropomins, including Bathyanthias, are monophyletic with respect to Indo-Pacific Liopropoma, and that Bathyanthias is nested within Liopropoma, indicating a need for further study of the generic limits of Liopropoma. The phylogenetic data also suggest that western Atlantic liopropomins comprise three monophyletic clades that have overlapping depth distributions but different depth maxima (3–135 m, 30–150 m, 133–411 m). The new species has the deepest depth range (182–241 m) of any known western Atlantic Liopropoma species. Both allopatric and depth-mediated ecological speciation may have contributed to the evolution of western Atlantic Liopropomini.     

A new species of the Boophis rappiodes group (Anura,Mantellidae) from the Sahamalaza Peninsula,northwest Madagascar,with acoustic monitoring of its nocturnal calling activity

A new species of treefrog of the Boophis rappiodes group (Anura, Mantellidae) is described from the Sahamalaza – Iles Radama National Park in northwest Madagascar. This new species is green in colour with bright red speckling across its head and dorsum; similar in morphology to other species of this group including: B. bottae, B. rappiodes, B. erythrodactylus and B. tasymena. The new species can be distinguished by its advertisement call and by a genetic divergence of more than 4.9% in the analysed mitochondrial 16S rRNA gene fragment. Its call consists of two note types: a trill and a click; although similar sounding to B. bottae, the trill note of the new species has a faster pulse rate while the click note is predominantly two-pulsed rather than three. All individuals were detected from the banks of two streams in Ankarafa Forest. The new species represents the only member of the B. rappiodes group endemic to Madagascar’s western coast, with the majority of other members known from the eastern rainforest belt. Despite its conspicuous call, it has not been detected from other surveys of northwest Madagascar and it is likely to be a local endemic to the peninsula. The ranges of two other amphibian species also appear restricted to Sahamalaza, and so the area seems to support a high level of endemicity. Although occurring inside a National Park, this species is highly threatened by the continuing decline in the quality and extent of its habitat. Due to these threats it is proposed that this species should be classified as Critically Endangered according to the IUCN Red List criteria.     

A synopsis of the tribe Lachnophorini,with a new genus of Neotropical distribution and a revision of the Neotropical genus Asklepia Liebke, 1938 (Insecta,Coleoptera, Carabidae)

This synopsis provides an identification key to the genera of Tribe Lachnophorini of the Western and Eastern Hemispheres including five genera previously misplaced in carabid classifications. The genus Asklepia Liebke, 1938 is revised with 23 new species added and four species reassigned from Eucaerus LeConte, 1853 to Asklepia Liebke, 1938. In addition, a new genus is added herein to the Tribe: Peruphorticus gen. n. with its type species P. gulliveri sp. n. from Perú. Five taxa previously assigned to other tribes have adult attributes that make them candidates for classification in the Lachnophorini: Homethes Newman, Aeolodermus Andrewes, Stenocheila Laporte de Castelnau, Diplacanthogaster Liebke, and Selina Motschulsky are now considered to belong to the Lachnophorini as genera incertae sedis. Three higher level groups are proposed to contain the 18 recognized genera: the Lachnophorina, Eucaerina, and incertae sedis.Twenty-three new species of the genus Asklepia are described and four new combinations are presented. They are listed with their type localities as follows: (geminata species group) Asklepia geminata (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil; (hilaris species group) Asklepia campbellorum Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia demiti Erwin & Zamorano, sp. n., circa Rio Demiti, Brazil, Asklepia duofos Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia hilaris (Bates, 1871), comb. n, São Paulo de Olivença, Brazil, Asklepia grammechrysea Zamorano & Erwin, sp. n., circa Pithecia, Cocha Shinguito, Perú, Asklepia lebioides (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia laetitia Zamorano & Erwin, sp. n., Leticia, Colombia, Asklepia matomena Zamorano & Erwin, sp.n., 20 km SW Manaus, Brazil; (pulchripennis species group) Asklepia adisi Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia asuncionensis Erwin & Zamorano, sp. n., Asunción, Río Paraguay, Paraguay, Asklepia biolat Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia bracheia Zamorano & Erwin, sp. n., circa Explornapo Camp, Río Napo, Cocha Shimagai, Perú, Asklepia cuiabaensis Erwin & Zamorano, sp. n., Cuiabá, Brazil, Asklepia ecuadoriana Erwin & Zamorano, sp. n., Limoncocha, Ecuador, Asklepia kathleenae Erwin & Zamorano, sp. n., Belém, Brazil, Asklepia macrops Erwin & Zamorano, sp. n., Concordia, Río Uruguay, Argentina, Asklepia marchantaria Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia marituba Zamorano & Erwin, sp. n., Marituba, Ananindeua, Brazil, Asklepia paraguayensis Zamorano & Erwin, sp. n., San Lorenzo, Rio Paraguay, Paraguay, Asklepia pakitza Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia pulchripennis (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia samiriaensis Zamorano & Erwin, sp. n., Boca del Río Samiria, Perú, Asklepia stalametlitos Zamorano & Erwin, sp. n., Guayamer, Río Mamoré, Bolivia, Asklepia strandi Liebke, 1938, Guyana, Asklepia surinamensis Zamorano & Erwin, sp. n., l’Hermitage, Surinam River, Surinam, Asklepia vigilante Erwin & Zamorano, sp. n., Boca del Río Samiria, Perú. Images of adults of all 18 genera are provided.     

Phenotypic and Genotypic Analysis of Newly Obtained Interspecific Hybrids in the Campanula Genus

Interspecific hybridisation creates new phenotypes within several ornamental plant species including the Campanula genus. We have employed phenotypic and genotypic methods to analyse and evaluate interspecific hybridisation among cultivars of four Campanula species, i.e. C. cochleariifolia, C. isophylla, C. medium and C. formanekiana. Hybrids were analysed using amplified fragment length polymorphism (AFLP), flow cytometry and biometrical measurements. Results of correlation matrices demonstrated heterogeneous phenotypes for the parental species, which confirmed our basic premise for new phenotypes of interspecific hybrids. AFLP assays confirmed the hybridity and identified self-pollinated plants. Limitation of flow cytometry analysis detection was observed while detecting the hybridity status of two closely related parents, e.g. C. cochleariiafolia × C. isophylla. Phenotypic characteristics such as shoot habitus and flower colour were strongly influenced by one of the parental species in most crosses. Rooting analysis revealed that inferior rooting quality occurred more often in interspecific hybrids than in the parental species. Only interspecific hybrid lines of C. formanekiana ‘White’ × C. medium ‘Pink’ showed a high rooting level. Phenotype analyses demonstrated a separation from the interspecific hybrid lines of C. formanekiana ‘White’ × C. medium ‘Pink’ to the other clustered hybrids of C. formanekiana and C. medium. In our study we demonstrated that the use of correlation matrices is a suitable tool for identifying suitable cross material. This study presents a comprehensive overview for analysing newly obtained interspecific hybrids. The chosen methods can be used as guidance for analyses for further interspecific hybrids in Campanula, as well as in other ornamental species.     

Morpho-Molecular and Ultrastructural Characterization of Discocriconemella Parasinensis n. Sp. from Zhejiang Province,China

During a recent inventory survey of the nematofauna of tea plantation at Zhejiang Province, China, Discocriconemella parasinensis n. sp. was detected in the rhizosphere of Camellia sinensis. The new species can be characterized by having the uninterrupted rounded labial disc, en face view showing rectangular-rounded labial plate without submedian lobes, R = 82.6 (80–86), Rex = 22 (21–23), stylet length of 68.3 (59–76) μm, excretory pore located 1–2 annuli posterior to the esophageal bulb, vulva open, postvulval body elongated conoid, and tail conoid with bilobed terminus. Morphologically, the species shares the same lip-type with D. discolabia, D. mauritiensis, D. mineira, D. perseae, and D. sinensis. Phylogenetic relationships of the new species based on D2–D3 expansion segments of 28S, ITS, and 18S rRNA genes revealed that D. parasinensis n. sp. formed a separated clade from other criconematid species, thereby supporting its status as a new species of the genus. The new species showed close phylogenetic relationships with Criconemoides geraerti.     

Two New and Two Recharacterized Species from a Radiation of Pristionchus (Nematoda: Diplogastridae) in Europe

Two new species of Pristionchus, P. lucani n. sp. and P. bulgaricus n. sp., are described from France and Bulgaria, respectively. Additionally, new morphological and morphometric data are provided for two previously described species from Europe, P. brevicauda (Kotlán, 1928) Paramonov, 1952 and P. clavus (von Linstow, 1901) Sudhaus and Fürst von Lieven, 2003. A phylogeny including these four species was inferred from a dataset including 26 ribosomal protein-coding genes, sequences of which are original for P. bulgaricus n. sp. and P. clavus. Relationships support a radiation of all sequenced European Pristionchus species from a single, gonochoristic common ancestor, and current knowledge of species ranges supports “western” and “eastern” clades. Similar diagnostic morphologies reflect the close relationships among the new and recharacterized species, especially P. bulgaricus n. sp., P. brevicauda, and P. clavus, although mating tests as well as genetic and phylogenetic separation support their identities as unique species. Our results show that Pristionchus species in Europe are more diverse than typological characters suggest, and thus biological and molecular profiling will be essential for future delimitation of Pristionchus species from the region.     

Three new species of Liparis s.l. (Orchidaceae: Malaxideae) from Southwest China based on morphological characters and phylogenetic evidence

Liparis aureolabella and L. mengziensis, two new species from the karst region of southwestern China, and L. bingzhongluoensis, a new species from montane region in Yunnan, are described and illustrated. L. aureolabella is easily distinguished from its relatives by having abaxially purple leave with purple reticulate veins prominent adaxially, a lip auriculate at base, and falcate-lanceolate pollinia. Liparis mengziensis is closely related to L. petiolata and L. auriculata, but differs from them by having an ovate to broadly ovate leaf, purple lip and apex connate along the margins. Liparis bingzhongluoensis is similar to Liparis nanlingensis, but the new species is characterized by having a lip with two transparent ridges on its disc, longitudinally concave basal callus and triangular column wings. Phylogenetic analyses based on nuclear ribosomal ITS and plastid matK sequences showed that L. aureolabella and L. mengziensis are nested with L. petiolata or L. auriculata in a monophyletic clade. L. bingzhongluoensis is sister to a clade formed by L. nanlingensis, L. tsii, L. sasakii and L. krameri. Moreover, morphological comparisons strongly support that the three species as separated species newly to science.     

Four new species and a new record of Orchidinae (Orchidaceae: Orchideae) from China

Four new species of Orchidaceae from China, Heminium lijiangense, Peristylus fasciculatus, Platanthera milinensis, and Ponerorchis gongshanensis, together with a new country record, Peristylus tenuicallus, are described and illustrated based on morphological and/or phylogenetic analyses. Heminium lijiangense is closely related to H. elisabethae but differs from it by having the dorsal sepal ovate-orbicular and lip mid-lobe distinctly shorter than lateral lobes. P. fasciculatus is close to Peristylus tradescantifolius but is distinguished from it by having several fascicled and straight, root-like tubers (vs. one or two oblongoid tubers), old stems usually persistent, middle lobe of lip narrowly ligulate-lanceolate and half as long as the lateral lobes (vs. middle lobe deltoid, about a third as long as the lateral lobes or less), a raised callus at the base of each lateral lobe (vs. callus absent), spur gradually attenuate toward the apex (vs. spur clavate). Platanthera milinensis is similar to P. stenochila by sharing small green flowers and lip without a spur, but differs in having a creeping rhizome, a corymbose inflorescence, and a broadly ovate and slightly 3-lobed lip. Ponerochis gongshanensis is similar to P. faberi in its small flowers, but differs in having a linear leaf c. 3 mm wide (vs. leaf 5–13 mm wide), in the lip having collar-like raised margins on the sides of the spur entrance, and a mid-lobe which is notched at the apex but not divided into two divergent lobules that are nearly as large as the lateral lobes, as in P. faberi. All the proposed species obtained high support in phylogenetic analysis as new species. The recently described genus Apetalanthe is reduced to synonymy of Ponerorchis and a new combination is made.     

Molecular Phylogenetic Analysis Reveals the New Genus Hemisphaericaspora of the Family Debaryomycetaceae

Four strains of a novel ascomycetous yeast species were recovered from the frass of wood-boring beetles collected from the Baotianman Nature Reserve and the Laojieling Nature Reserve in Henan Province, China. This species produced unconjugated and deliquescent asci with hemispheroid or helmet-shaped ascospores. Analysis of gene sequences for the D1/D2 domain of the large subunit (LSU) rRNA, as well as analysis of concatenated gene sequences for the nearly complete small subunit (SSU) rRNA and D1/D2 domain of the large subunit (LSU) rRNA placed the novel species in a small clade including only one recognised species, Candida insectamans, in the family Debaryomycetaceae (Saccharomycotina, Ascomycota). DNA sequence analyses demonstrated that the novel species was distinct from all currently recognised teleomorphic yeast genus. The name Hemisphaericaspora nanyangensis gen nov., sp. nov. is proposed to accommodate the novel genus and species. The new genus can be distinguished from closely related teleomorphic genera Lodderomyces and Spathaspora through sequence comparison and ascospore morphology. The ex-type strain of H. nanyangensis is CBS 13020^T ( = CICC 33021 = NYNU 13717). Furthermore, based on phenotypic and genotypic characteristics, C. insectamans is transferred to the newly described genus as Hemisphaericaspora insectamans comb. nov., in accordance with the changes in the International Code of Nomenclature for algae, fungi and plants.     

Molecular perspective on the American transisthmian species of Macrobrachium (Caridea,Palaemonidae)

The closure of the Isthmus of Panama (about 3.1 million years ago) separated previously continuous populations and created two groups of extant species, which live now in the Pacific and Atlantic drainage systems. This relatively recent event was a trigger to diversification of various species in the Neotropics, nonetheless there are exemplars that do not show sufficient morphologic variability to separate them by traditional morphological tools. About 60 years ago, some freshwater decapod species with high morphological similarity were separate by previous researchers, based on geographical distribution, in Pacific and Atlantic and considered as “sister species”. However, the complete isolation of these prawns by this geographical barrier is questionable, and it has generated doubts about the status of the following transisthmian pairs of sibling species: Macrobrachium occidentale × Macrobrachium heterochirus, Macrobrachium americanum × Macrobrachium carcinus, Macrobrachium digueti × Macrobrachium olfersii, Macrobrachium hancocki × Macrobrachium crenulatum, Macrobrachium tenellum × Macrobrachium acanthurus and Macrobrachium panamense × Macrobrachium amazonicum. Here we evaluated the relation among these pairs of sibling species in a molecular phylogenetic context. We generated 95 new sequences: 26 sequences of 16S rDNA, 25 of COI mtDNA and 44 of 18S nDNA. In total, 181 sequences were analyzed by maximum likelihood phylogenetic method, including 12 Macrobrachium transisthmian species, as well as seven other American Macrobrachium species, and two other palaemonids. Our analysis corroborated the morphological proximity of the sibling species. Despite the high degree of morphological similarities and considerable genetic diversification encountered among the transisthmian sister species, our data support the conclusion that all species included in sibling groups studied herein are valid taxonomic entities, but not all pairs of siblings form natural groups.