Libitioides Roewer 1912
Creators: name: Kury, Adriano B.
name: Medrano, Miguel
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Cosmetidae
Libitioides

description: Genus Libitioides Roewer, 1912
Libitioides Roewer, 1912: 14 [junior subjective synonym of Vonones Simon, 1879 by Goodnight & Goodnight (1953a: 60); synonymy disclaimed by Medrano et al. (2021: 26)]. Type species by original designation: Libitioides ornata Roewer, 1912.
Platycynorta Mello-Leitão, 1933: 112. Type species by original designation: Cynorta depressa Sørensen, 1932. Syn. nov.
Denticynorta Roewer, 1947: 9 [junior subjective synonym of Vonones Simon, 1879 by Goodnight & Goodnight (1953a); synonymy disclaimed by Kury (2003). Type species by original designation: Metacynorta denticus Walker, 1928. Syn. nov.
Diagnosis
Scutum outline lambda-type, scutum flattened in lateral view, lateral border in posterior view clearly marked by a deep groove and raised to break the outline of scutum. Protoglyph guards are blunt triangular. Mesotergal grooves are obsolete. Scutal areas I, III and IV each with a pair of blunt tubercles (L. ornata: area III with robust spines tilted backwards and IV unarmed). Cheliceral hand and basichelicerite are sexually monomorphic. Legs moderately elongate (femora II and IV barely longer than scutum). Coxa and trochanter IV of male almost entirely parallel to the main body axis, so that femur IV lies straight, while in females the coxa/trochanter are inserted more obliquely and the femur is slanted. Coxa IV surpasses coda in situ only by its apical region, with well developed proapical apophysis and without groin warts. Femur IV sexually dimorphic, in male more thickly granulous and straight, in female thinner and curved proximally. Basitarsus I thickened in male. Tarsal counts: 5(3)/8–9(3)/6/6. Male genitalia: VP subrectangular. Wattle extends from the middle to the tip of the stylus. MS D1 is almost as large as C. Two long lateral patches of microsetae T4 without midfield.
Etymology
Libitioides from pre-existing genus Libitia + suffix ‘- oides ’. Gender feminine, originally established by Roewer by inflecting the adjectival specific nomina in the feminine (ICZN Art. 30.1.4.4). Platycynorta from Greek ‘πλατύς’ (‘flat’) + pre-existing genus Cynorta. Gender feminine. Denticynorta from Latin ‘ dens ’ (‘tooth’) + pre-existing genus Cynorta. Gender feminine.
Placement
Libitioides, Platycynorta and Denticynorta originally in Cosmetidae Cosmetinae; left as Cosmetidae incertae sedis by Medrano et al. (2021).
Included species
Libitioides albolineata (Sørensen, 1884), Libitioides modesta (Banks, 1909) nom. rest., Libitioides ornata (Say, 1821), Libitioides sayi (Simon, 1879) and Libitioides scabrissima Roewer, 1912.
Spurious included species
Because the relevant genera were heterogeneous to begin with, there was a legacy of species of uncertain taxonomic position and which are all treated here: Platycynorta secunda Roewer, 1947 (Cuba), Platycynorta clavifemur Roewer, 1957 (Peru), Libitioides riveti Roewer, 1914 (Ecuador).
Combined distribution
Cuba, NE tip of Mexico, eastern/southeastern USA (map in Fig. 13).
Comment on relationships
Libitioides resolved as the sister-group of the Taitoinae in the phylogenetic analysis of Medrano et al. (2021). The authors, however, then refrained from including it in this subfamily because of the low resampling support, choosing instead to present a tighter Taitoinae (better supported by synapomorphies) as opposed to the “quasi-taitoine” with Libitioides. We here note that Libitioides seems to be also very closely related to the genera Paravonones Pickard-Cambridge, 1904 and Boneta Goodnight & Goodnight, 1944, which currently include six nominal species from Mexico, El Salvador and Guatemala and were not included in that analysis. Both genera share the scutal outline and armature, the vaulted laterals of dorsal scutum, monomorphic chelicerae, the sexually dimorphic insertion of coxa and trochanter IV. The species of Paravonones contrast with Libitioides by possessing more sinuous leg IV on males, with stronger armature. The type species of Boneta is very similar to Libitioides, contrasting with it by having remarkably granulated coxae.
Key to the species of Libitioides
1. Body densely covered with coarse granules; spines of area III small and curved backwards like a rose thorn; scutal area IV unarmed .................... L. scabrissima Roewer, 1912 comb. rest. (Mexico)
– Body finely granular; scutal area III with pair of strong spines tilted backwards .............................. ................................................................................... L. ornata (Say, 1821) (USA, Florida, Georgia) – Body finely granular; scutal areas III and IV armed with very small erect acuminate tubercles ..... 2
2. Retrolateral (“inner”) surface of femur IV with densely concentrated rows of granules ................. 3
– Granulation of femur IV not especially concentrated on retrolateral surface ..................................... ................................................................... L. modesta (Banks, 1909) comb. nov., nom. rest. (Cuba)
3. Backbone and ribs present; chevron complete or nearly complete; body and appendages background almost always uniform brown; paired darker spots on scutal area III indistinct .................................................................. L. albolineata (Sørensen, 1884) (eastern USA)
– Backbone and ribs always lacking; chevron always dissociated; body mustard yellow with a pair of much darker spots on scutal area III .................................................................................................... ................................. L. sayi (Simon, 1879) (USA, only in Arkansas, Kansas, Oklahoma and Texas)
description: Published as part of 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), pp. 101-141 in European Journal of Taxonomy 875 (1) on pages 123-125, DOI: 10.5852/ejt.2023.875.2143, http://zenodo.org/record/8064424