Arachnids of North Carolina
Scientific Name: Common Name: Family (Alpha):
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View Sclerosomatidae Members: NC Records

Hadrobunus fusiformis Shultz, 2010 - No Common Name

Order: OPILIONESSuborder: EupnoiSuperfamily: PhalangioideaFamily: Sclerosomatidae                                                                                 
Comments: Hadrobunus currently comprises four species that occur in North America north of Mexico (Cokendolpher and Lee, 1993; Shultz, 2010, 2012). However, Shultz (2010, 2018) and Burns et al. (2012) note that several undescribed species exist and that Leiobunum formosum will be tranferred to Hadrobunum based on genetic analysis. Only Hadrobunus maculosus and H. fusiformis have so far been documented in North Carolina (L. formosum has one old record from Wake County).
Species Comment: The type specimens were collected in 1939 by Rehn and Rehn at Smokemont, GRSMNP, Swain County (see Shultz, 2010)
Online Description/Photos: BugGuide Google, iNaturalist, Wikipedia, GBIFTechnical Description: Shultz (2010)
Comments: Males are dark brown dorsally (Shultz, 2010). The scutum of the abdomen has a dark saddle that narrows towards the posterior end. The scutum is also crossed by six rows of light spots separated by bands that are uniform in color. The females are colored similarly but the rows of light spots on the last tergite of the scutum may be fused to form short stripes. The palps and pedal trochanters in both sexes are yellow-brown, unlike the dark, mottled brown characteristic of maculosus.
Total Length: 7.4 mm, male holotype; 9.4 mm, female paratype (Shultz, 2010)Adult ID: identifiable by photo of specific features and/or supplementary info
Structural Features: As in H. maculosus, the femur of the first leg is shorter than the body. The abdomen of the male is distinctively fusiform; that of the female is also elongated (Shultz,2010). Shultz provides a number of other morphological differences that separate the currently described species of Hadrobunus, particularly genitalic characters (see Shultz, 2010, 2012 for illustrations and more detailed descriptions).
Structural photos

Venter, female collected by S. Hall and J.B. Sullivan in Ashe County, 2019-06-02

Close-up of genital operculum, female collected by S. Hall and J.B. Sullivan in Ashe County, 2019-06-02
Distribution in North Carolina
Comments: Records for this species come from the Southern Appalachians of North Carolina and adjoining Georgia, but also from the outer Coastal Plain of South Carolina and Georga (Shultz, 2010)
County Map: Clicking on a county returns the records for the species in that county.
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 in North Carolina at fairly low elevations in the Mountains but at 4,000-5,000' at one site. It has also been recorded in coastal South Carolina and Georgia (Shultz, 2010) and was recorded at a wide range of habitats at the Savannah River Plant in Georgia (Draney and Shultz, 2016).
Observation Methods: No information on the activity patterns appear to exist. Like H. maculosus, it may be active mainly at night.
Abundance/Frequency: Collected in fairly large numbers on one occasion at Mt. Pisgah; also collected multiple times at a site in Macon County
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 preserves
Comments: The distribution, habitat associations, abundance, and population trends are still too poorly known to estimate the conservation status of this species in North Carolina. Its presence in both the Southern Appalachians and the Coastal Plain of South Carolina and Georgia suggests that it could be actually fairly widespread and generalized in terms of its habitats.

 Photo Gallery for Hadrobunus fusiformis - No common name

Photos: 2

Recorded by: Steve Hall and Bo Sullivan on 2019-07-02
Ashe Co.
Comment: Adult female
Recorded by: Steve Hall and Bo Sullivan on 2019-07-02
Ashe Co.