Arachnids of North Carolina
Order:
Scientific Name: Common Name: Family (Alpha):
« »
View SCLEROSOMATIDAE Members: NC Records

Leiobunum bracchiolum McGhee 1977 - No Common Name

No image for this species.
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. politum.
Identification
Online Description/Photos: BugGuide Google, iNaturalist, Wikipedia, GBIFTechnical Description: McGhee (1977); Shultz (2018)
Comments: Males are pale yellowish with no distinct markings (McGhee, 1977). Females are similarly pale yellowish but can have a central figure on the abdomen that varies from well-developed to obscure and from very light brown to dark brown. Shultz (2018) adds that the central figure in bracchiolum is restricted to the abdomen but may extend onto the carapace in politum. Otherwise, bracchiolum and politum are very similar in appearance and distinguishable primarily based on size and structural differences.
Total Length: 2.0-3.5 mm, males; 3.5-5.5 mm, females (McGhee, 1977)Adult ID: identifiable from specimen only
Structural Features: According to McGhee (1977), bracchiolum is best distinguished from politum based on size and reproductve structures.
Distribution in North Carolina
Comments: Our sole record comes from the central Piedmont. However, McGhee (1977) states that it is most common in the Appalachians, with at least one record shown in the range map for this species coming from close to the North Carolina-Tennessee line.
County Map: Clicking on a county returns the records for the species in that county.
Leiobunum bracchiolum
Adult phenology:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Habitats and Life History
Habitats: Found along forest edges in Maryland (Shultz, 2018)
Observation Methods: Shultz (2018) describes bracchiolum as more commonly found up on vegetation than L. politum, which is usually found on the forest floor
Abundance/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] [SU]
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 preserves
Comments: We have only a single recent (2007) and confirmed record for this species. While this species does not appear to be habitat limited, 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.