Libitioides, Roewer, 1912

Kury, Adriano B. & Medrano, Miguel, 2023, Once upon a time in America: recognition of the species of Libitioides from USA, with comments on other American Cosmetidae (Opiliones, Laniatores), European Journal of Taxonomy 875 (1), pp. 101-141 : 110-113

Recognition of morphs in Libitioides

We can recognize five morphs for the American species treated herein ( Fig. 6 ), two pairs of them (B, C and D, E) merge into each other. Their marked features are listed below:

Morph A: Libitioides ornata ( Fig. 6a ). The strongly spined and profusely marked Floridan species. It seems endemic to the WWF ecoregion NA0529 (Southeastern conifer forests).

Morph B: “clean” Libitioides sayi ( Fig. 6b ). The Texan unmarked caramel Libitioides sayi ( Simon, 1879) to the eastern part of Texas, Oklahoma and Kansas. This morph occurs exclusively in the type 8 biome of WWF (Temperate Grasslands, Savannas, & Shrublands), massively in WWF ecoregion NA0804 (Central forest-grasslands transition), extending marginally also into NA0805 (Central tall grasslands) and NA0806 (Edwards Plateau savanna).

Morph C: Libitioides sayi , morph “ depressa ” ( Fig. 6c ). The striped Texan morph recognized (but not named) by Weed is not viewed here as a separate species, which would have been properly called Libitioides depressa (Sørensen, 1932) . This morph may be recognized by the caramel color (with dark patches on area III) just as in the typical L. sayi , but possessing a reduced arched chevron and well-formed omega-stripe almost as solid as in L. albolineata . Accordingly, Roewer’s Platycynorta transversalis fits with this morph but without any chevron. It occurs intertwined with the more typical L. sayi D morph, mainly in the Gulf Coastal Plain of Texas. WWF ecoregions: NA0523 (Piney Woods forests), NA0701 (Western Gulf coastal grasslands), NA0814 (Texas blackland prairies).

Morph D: Libitioides albolineata ( Fig. 6d ). The broad definition of Vonones sayi (sensu Cokendolpher & Jones 1991) is not supported here, so we recognize the widespread northeastern-most species (from Appalachian Highlands, including Piedmont, and Interior Plains, outspreading into Atlantic Plain) as Libitioides albolineata ( Sørensen 1884) comb. nov. This species has a tuning-fork chevron (with a clear backbone at least over area I), omega-stripe open, arched frontwards, dissociated ribs, and dissociated marking on lateral areas. It occurs massively in the WWF biome 4 (Temperate Broadleaf & Mixed Forests), extending a little into biomes type 5 (Temperate Coniferous Forests) and 8 (Temperate Grasslands, Savannas, & Shrublands). WWF ecoregions with major occurrence of this species are: NA0402 (Appalachian mixed mesophytic forests), NA0403 (Appalachian-Blue Ridge forests), NA0404 (Central U.S. hardwood forests), NA0409 (Mississippi lowland forests), NA0412 (Ozark Mountain forests) and NA0413 (Southeastern mixed forests).

Morph E: “yellow Libitioides albolineata ” ( Fig. 6e ). It occurs in the contact zone of L. sayi and L. albolineata , restricted to a small area mainly in the Gulf Coastal Plain of Texas. WWF ecoregions: NA0523 (Piney Woods forests) and NA0701 (Western Gulf coastal grasslands).

We are also marginally dealing with other species associated with Libitioides and its synonyms as well as the monotypic Calicynorta , mistakenly reported as being from the USA.

Platycynorta clavifemur does not share any special similarity with any Libitioides . Its distribution in NW Peru already hints at the alienness of it compared to Libitioides . We made an effort to relate this species to the described Andean genera, and found special similarity with Ambatoiella Mello-Leitão, 1943 , so this species is below formally combined under that genus. Other genera from the Peruvian Andes such as Moselabius Roewer, 1956 and Socotabius Roewer, 1957 are surely closely related to Ambatoiella , and at least members of the Libitiinae , but in the absence of detailed information of those genera and of a phylogenetic analysis to test those hypotheses, we refrain from proposing a formal transfer.

Calicynorta bimaculata is very similar to Holovonones compressus , a common south Mexican species. As it is known by a female only, we do not know if there are significant contrasts between Costa Rican and Mexican/Guatemaltecan populations. There seems to be small differences in the scutal armature and the two longitudinal stripes. Therefore, we include C. bimaculata in Holovonones as a distinct species and assume that the Costa Rican H. compressus must be H. bimaculatus instead.

Figures

Fig. 6. Schemes of scutal yellow markings and other features diagnosing the morphs discussed herein. a. Morph A: Libitioides ornata (Say, 1821). b. Morph B: “clean” Libitioides sayi (Simon, 1879). c. Morph C: Libitioides sayi, striped Texan morph “depressa”. d. Morph D: Libitioides albolineata (Sørensen, 1884). e. Morph E: “yellow Libitioides albolineata”.