Dactylobiotus, Schuster, 1980

Dactylobiotus View in CoL morphogroups

The species of the genus Dactylobiotus can be divided into two morphogroups, distinguished by the presence or absence of papillae on the dorso-caudal portion of the body. Although this division currently lacks clear molecular confirmation, it remains useful for species classification during morphological analyses, as reported for other genera ( e.g., Massa et al. 2024; Vecchi et al. 2023; Kaczmarek and Michalczyk 2017; Stec 2022).

The D. dispar View in CoL morphogroup is characterized by the presence of flat or cone-shaped papillae in the dorso-caudal region of the body and includes the following species: D. dispar View in CoL , D. grandipes View in CoL , D. parthenogeneticus View in CoL , D. selenicus View in CoL , and D. taiwanensis sp. nov. The second group, the D. ambiguus View in CoL morphogroup, is characterized by the absence of papillae in the dorso-caudal region and comprises the following species: D. ambiguus View in CoL , D. ampullaceus , D. dervizi Biserov, 1998 View in CoL , D. haplonyx Maucci, 1980 View in CoL , D. luci Kaczmarek, Michalczyk and Eggermont, 2008 , D. octavi View in CoL , D. ovimutans , and D. vulcanus Kaczmarek, Schabetsberger, Litwin and Michalczyk, 2012 . Regarding egg morphology, the species within these morphogroups exhibit variable ornamentation, including eggs with small to large cones, sometimes bearing bi-, tri-, or poly-furcated apices. The surface between egg processes may be smooth, porous, or wrinkled. Despite this variability, the most common eggs in both groups feature small conical processes that are uniform in size and shape. These processes are sometimes furcated but never bear filaments and are always well-spaced from one another. Future phylogenetic analyses with expanded taxonomic and phylogenetic sampling will provide a better understanding of the value of morphological characters, allowing greater phylogenetic significance to be assigned to features such as dorso-caudal papillae or egg ornamentation. However, given the evolutionary convergence observed in another genus ( Murrayon View in CoL ) regarding egg morphology and the previously documented high rate of morphological evolution in egg ornamentation ( Guidetti et al. 2013; Stec et al. 2016 2021), it is anticipated that dorso-caudal papillae (never observed in close relatives of Dactylobiotus View in CoL ) will hold greater phylogenetic relevance. Although our phylogenetic analyses were based on a dataset that remains phylogenetically and taxonomically limited, we believe that a congruence with the morphogroup division is already evident in the provided phylogeny. Specifically, all Dactylobiotus View in CoL taxa in our dataset that

Animals - absolute values

Animals - rela�ve values ( pt)

Eggs

D. parthenogeneticus

D. taiwanensis sp. nov.

exhibit dorsal papillae ( D. grandipes , D. selenicus , D. parthenogeneticus , and D. taiwanensis sp. nov.) cluster together to form a well-supported clade. However, the relationship of this clade with other Dactylobiotus taxa remains poorly supported in our analyses ( Fig. 1 View Fig ).