Taxonomy
Order: OPILIONESSuborder: EupnoiSuperfamily: PhalangioideaFamily: Sclerosomatidae Comments: Approximately 30 species in this genus have been identified as occurring in North America north of Mexico (Cokendolpher and Lee, 1993; Ingianni et al., 2011), with 16 recorded in North Carolina. However, the validity of several of these species is suspect, with several that will probably be determined to be synonyms of other species, e.g., davisi, speciosum, and zimmermani in North Carolina Burns et al., 2012; Shultz, 2018). According to Shultz (2018), moreover, recent phylogenetic studies indicate both that more species are waiting to be described and that the name Leiobunum may eventually be restricted to European species, requiring new generic names for most, if not all, of our species.Species Comment: Placed in the Leiobunum Politum Species Group by Burns et al. (2012) based on reproductive structures as well as genetic analysis. In North Carolina, this group also includes L. bracchiolum.
Identification
Online Description/Photos: BugGuide Google , iNaturalist , Wikipedia , GBIF Technical Description: Davis (1934); Shultz (2018)Comments: Males are golden-yellow to red-brown above, with no central figure on the abdomen; the ventral surface is similar in color but lighter. The palps are also similar in color as are the trochanters and basal portions of the femurs of the legs; the legs are dark brown distally (Davis, 1934). Females are yelowish- to reddish- to purplish brown, with a central figure that extends across the carapace and abdomen but is often somewhat incomplete; transverse bands of yellowish spots are present on the abdomen (Shultz, 2018). Leiobunum flavum is similar in color, including yellowish coxae, trochanters, and femur bases, but has more uniformly pale legs, is larger, and appears earlier in the season than politum. Leiobunum bracchiolum is also similar in appearance to politum but is slightly larger. Females have a central figure that is restricted to the abdomen (Shultz, 2018). Males may require dissection in order to distinguish politum from bracchiolum.Total Length: 4.8 mm, males; 6 mm, females (Davis, 1934)Adult ID: identifiable by photo of specific features and/or supplementary infoStructural Features: Male and female reproductive structures are diagnostic (see Davis, 1934; Shultz, 2018)
Distribution in North Carolina
Comments: We have records from both the Piedmont and Mountains but some of these were made prior to the separation of bracchiolum from politum and need to be verified through collection of modern specimensCounty Map: Clicking on a county returns the records for the species in that county.
Adult phenology: Click on graph to enlarge
Habitats and Life History
Habitats: Found along forest edges in Maryland (Shultz, 2018) Observation Methods: Shultz (2018) describes politum as more commonly found on the forest floor than bracchiolum, which is usually found up on vegetationAbundance/Frequency: We currently have too few records from North Carolina to judge its frequency of occurrence or abundance
Status in North Carolina
Natural Heritage Program Status: Natural Heritage Program Ranks: [GNR] [S3S5]State Protection: Arachnids are not protected under state law, although permits are needed to collect them in State Parks and other public and private nature preservesComments: While this species does not appear to be habitat limited, but we need much more information on its distribution in the state, its habitat preferences, and population trends before we can begin to estimate its conservation status.
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