Table 4 in The xerophilic genera Xerobiotus and Pseudohexapodibius (Macrobiotidae; Tardigrada): biodiversity, biogeography and phylogeny

Table 4. Comparisons of the morphological characters present in the Xerobiotus species considered in this study. Unless specified otherwise, all the structures considered are visible with light microscopy (Xerobiotus pseudohufelandi was not included owing to unclear morphology).
SpeciesLegs I–IIILegs IVFurbelow-like structureKaryotypeReproductionEgg surface andClawThickeningsClawLunulesCuticularMicrodigitationsprocessesthickeningX. arenosumThin base, acutePresent (as plate;ProximalAbsentPresent, ringConicalTetraploid,ParthenogeneticProcesses with smallangle betweenvisible withconstric-shaped with24 chromo-and convex ter-branchesSEM)tionirregular mar-somes (4 n)minal disc withgins (with airregular taperedlarge plate;indentationvisible withSurface with denselySEM)distributed poresX. euxinusSmall, acutePresent, withSmallPresent withPresent, ringConicalDiploid,BisexualProcesses with smallangle betweensemilunarindentedshaped with6 chromosomesterminal disc withbranchesshape (asmargins;irregular mar-(2 n)regular indentationplates; visiblenot clearlyginsSurface with denselywith SEM), notvisible indistributed poresalways visibletype ma-terialX. gretaeThick base,AbsentCommonPresent?PresentConicalProcesses with smalltriangulartract longerand concave ter-commonthan mainminal disc withtract, rightbranch.regular taperedangle betweenBasal partindentationbranches.with en-Surface wrinkled andBasal part withlargementscaưered with dot-enlargementlike poresX. inermisSmallAbsentSmallPresentSmall and concaveterminal discSurface with denselydistributed poresX. litusThick base,AbsentEnlargedAbsentPresent, ringConicalBisexualProcesses with largetriangularproximalshaped withand convex ter-commonportionirregularminal disc withtract, rightmarginsregular indentationangle betweenSurface with denselybranchesdistributed pores

表4 本研究涉及的干燥熊虫属（Xerobiotus）各物种的形态特征比较。除另有说明外，所有观测结构均可通过光学显微镜观察（因形态特征不明，未纳入胡夫兰干燥熊虫（Xerobiotus pseudohufelandi））。

| 物种 | 第I-III对足 | 第IV对足 | 类腹毛结构 | 爪增厚 | 爪月状结构 | 爪突 | 表皮微指状突 | 核型 | 生殖方式 | 卵表面 |
|------|------------|----------|------------|--------|------------|------|--------------|------|----------|--------|
| X. arenosum | 基部纤细，爪分支间夹角尖锐（可通过扫描电子显微镜（SEM）观测） | 呈板状，收缩形且边缘不规则（气室凹陷可通过SEM观测） | 近端增厚 | 缺失 | 具大型板状结构的环状结构 | 圆锥形 | 具小分支，端盘边缘不规则渐窄 | 四倍体，含24条染色体（4n） | 孤雌生殖 | 表面密布细小孔隙 |
| X. euxinus | 小型，尖锐 | 呈板状的半月形（可通过SEM观测，模式标本中该结构不清晰） | 小型，边缘具凹陷 | 存在 | 环状结构 | 圆锥形 | 具小分支，端盘具不规则凹陷 | 二倍体，含6条染色体（2n） | 雌雄异体 | 表面密布细小孔隙 |
| X. gretae | 基部粗壮，爪柄长于主分支，分支间夹角为直角，基部具膨大结构 | 缺失 | 常见 | 情况不明 | 环状结构 | 圆锥形，常见，端盘具不规则渐窄的凹陷，基部具膨大结构 | 具小分支 | 信息不全 | 信息不全 | 表面具褶皱并散布点状孔隙，基部具膨大结构 |
| X. inermis | 小型 | 缺失 | 小型 | 存在 | 小型凹陷端盘 | 信息不全 | 信息不全 | 信息不全 | 信息不全 | 表面密布细小孔隙 |
| X. litus | 基部粗壮，爪近端部分膨大，分支间夹角为直角，端盘边缘不规则且具规整凹陷 | 缺失 | 膨大 | 缺失 | 环状结构 | 圆锥形，常见 | 具大分支，端盘边缘不规则 | 信息不全 | 雌雄异体 | 表面密布细小孔隙 |