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Summary: A new species of Aporcelinus , collected in a natural habitat of central Mexico, is described and illustrated, including molecular (D2-D3 28 S -rRNA) data. Aporcelinus zapotitlanensis sp. n. is characterised by its 1.19-1.43 mm long body, lip region offset by a deep constriction and 16.5-18.5 μ m broad, odontostyle 19.5-22 long, neck 325-368 μ m long, pharyngeal expansion 150-201 μ m long or 46-55% of the total neck length, uterus 130-167 μ m long and tripartite, V = 54-56, tail conical with finely rounded tip (30-37 μ m, c = 34-43, c′ = 1.2-1.4) lacking a distinct dorsal concavity, spicules 48-51 μ m long, and 11-12 spaced ventromedian supplements with one or two of them located within the range of the spicules. Molecular analyses confirm the monophyly of Aporcelinus and places the new species within a clade shared with A. infundibulicaudatus and A. amazonicus. [ABSTRACT FROM AUTHOR]

Soil nematode abundance and MOTU diversity were estimated from a geographically broad area of Mexico that included four out of seven recognised vegetation types. Vegetation types were assessed for abundance and diversity of nematode communities and inferred ecological relationships between them. Soils were sampled from tropical rainforest, tropical dry deciduous forest, temperate coniferous forest and xerophytic shrub during 2013, 2014 and 2015. Fourteen sampling sites with ca 10-20 samples per site from 11 localities spread across Central Mexico were assessed. Altitudes sampled ranged from 113 m a.s.l. (tropical coastal plain) to 2400 m a.s.l. (Trans-Mexican Volcanic Belt). Samples were drawn from conserved and cultivated plots from each sampling site covering an area of ⩾100 m². A total of 13 263 individuals from 25 identified families of nematodes were collected. Family abundance and complementarity indices between sites revealed to some extent the affinities between vegetation types. Nevertheless, statistical analyses revealed no differences between nematode family abundances between sites, only between families across all sites. Molecular operational taxonomic units (MOTU) methods were employed as a framework to assess biodiversity. From these, 77 high-quality sequences for taxonomic barcoding were recovered and later identified with morphological traits. Only six sequences matched at a 98-99% level with those reported in GenBank. Sequences amounted to a total of 41MOTU, where 100% of theMOTU from both conserved and disturbed tropical rainforest, tropical dry deciduous forest and xerophytic shrub exhibited a ⩾3% cut-off genetic identity, whilst temperate coniferous forest and disturbed temperate coniferous forest showed 73% and 70% respectively. In addition, 12.2% MOTU were shared among localities and 87.8% exhibited an apparently locality-limited distribution. The potential for a considerable diversity of nematodes, as revealed from a small sample of MOTU diversity, is discussed. [ABSTRACT FROM AUTHOR]

The aim of the present study was to detect the heterogeneity of diversity in seasonal, site, tree species, and soil properties' effects on structural and functional attributes of the nematode communities under smooth mesquite, Prosopis laevigata and palo brea, Cericidium praecox within the Biosphere Reserve Valle de Tehuacán-Cuicatlán. Soils under biological crusts and neighbouring exposed sites were surveyed during the dry and wet seasons of 2018. Assessment of effective diversity (D) and diversity weighted by metabolic footprint (DMFP) were calculated as they reflect taxonomic and functional diversity. Trophic group abundances and both indices showed marked seasonal variation. Soil water content and bulk density were the only physicochemical variables that showed seasonal variation whereas bulk density, total C and total N content showed significant variation between soil under biological crusts and exposed sites. DMFP seemed to have a better chance of explaining a relationship with physicochemical heterogeneity than D as shown by PCA analyses. This places DMFP as an index for measuring diversity related to ecosystem services and therefore should be used as a tool for biological integrity assessments at the soil level and a support aid in stewardship soil management policies. • Heterogeneity of desert nematode communities is related to seasonal change. • Seasonal water content determines changes in soil nematode functional diversity. • Seasonal changes were better represented by metabolic footprint indices. • Metabolic weighted diversity should be a tool for biological integrity surveys. [ABSTRACT FROM AUTHOR]