Arachnids of North Carolina
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View Sclerosomatidae Members: NC Records

Hadrobunus maculosus (Wood, 1868) - No Common Name

Taxonomy
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 Hadrobunus 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: In Shultz's 2012 review of Hadrobunus grandis, true grandis was described as restricted to Peninsular Florida and north in the Coastal Plain to southern South Carolina. Specimens from North Carolina northward previously identified as grandis are now believed to represent H. maculosus instead. One exception, however, is Banks' record for grandis from the Swannanoa River valley near Black Mountain, which Shultz indicated might represent H. fusiforms in his 2010 description of that species. We have accordingly moved the Buncombe County record to Hadrobunus unidentified species account; the rest are now treated as maculosus.
Identification
Online Description/Photos: BugGuide Google, iNaturalist, Wikipedia, GBIFTechnical Description: Shultz (2018)
Comments: A large, short-legged harvestman. Color varies from reddish brown to darker grayish brown. Shultz (2012) describes the coloration in Maryland populations as changing seasonally: early summer individuals have a light brown ground color with highly contrasting markings, rows of prominent spots, and distinct banding on the legs; late season individuals are much darker and have a much less constrasting pattern. The undersurface, including the coxae, are ivory. The pedal trochanters and the femur and patella of the palps are mottled dark and pale. The front margin of the carapace also has contrasting dark markings and a dark central figure is present in at least the early season forms.
Total Length: ~10 mm (Shultz, 2018)Adult ID: identifiable by photo
Structural Features: The body is relatively large but the legs are short, with the femur of the first leg shorter than the body (Shultz, 2018). The scutum of the abdomen is composed of six segments and is covered with minute, black, backward-pointing denticles. The genital operculum is distinctive in both sexes (see illustrations and descriptions in Shultz, 2012, 2018). In males, the anterior edge is indented, which can be seen in externally. The abdomen is bluntly rounded rather than fusiform, as it is in H. fusiformis.
Distribution in North Carolina
Comments: Currently, our records come from the Piedmont and Inner Coastal Plain; Shultz (2018) states that it ranges into western North Carolina. It seems likely that it will be documented statewide.
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: Shultz (2018) describes the habitat for this species as including "open or broken woodlands and adjacent non-wooded areas, including agricultural fields; less abundant in mature forests."
Observation Methods: "Adults largely nocturnal, found under loose objects on the ground during the day" (Shultz, 2018)
Abundance/Frequency: We currently have too few records to estimate either its frequency of occurrence or abundance in North Carolina
Prey: We have observed Hadrobunus to prey on insects as large as crane flies
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: [GNR] [S5]
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: This species probably occurs across most of the state and appears to be fairly generalized in terms of its habitat use. Although we still have few records for this species, we believe it is secure within the state.

 Photo Gallery for Hadrobunus maculosus - No common name

Photos: 20

Recorded by: Steve Hall and Bo Sullivan on 2021-10-03
Moore Co.
Comment: 		Recorded by: Steve Hall and Bo Sullivan on 2021-10-03
Moore Co.
Comment:
Recorded by: Steve Hall on 2021-09-30
Durham Co.
Comment: 		Recorded by: Steve Hall on 2020-06-13
Orange Co.
Comment:
Recorded by: Steve Hall on 2020-05-05
Orange Co.
Comment: 		Recorded by: Steve Hall on 2020-05-05
Orange Co.
Comment:
Recorded by: Steve Hall on 2019-09-24
Orange Co.
Comment: Adult female		Recorded by: Steve Hall on 2019-09-24
Orange Co.
Comment: Adult female
Recorded by: Steve Hall on 2019-06-01
Stokes Co.
Comment: Preying on a crane fly that it appeared to have captured on a moth sheet		Recorded by: Brian Bockhahn on 2019-06-01
Stokes Co.
Comment:
Recorded by: Steve Hall on 2019-05-30
Orange Co.
Comment: 		Recorded by: Steve Hall on 2019-05-30
Orange Co.
Comment: Truncated appearance apparently due to dehydration
Recorded by: Steve Hall on 2019-05-30
Orange Co.
Comment: 1st femur is shorter than the body; denticles visible on the dorsal surface of the abdomen		Recorded by: Steve Hall on 2019-05-30
Orange Co.
Comment: Female, lacking indented anterior margin of genital operculum
Recorded by: Steve Hall on 2019-05-25
Orange Co.
Comment: Found at night on a moth sheet		Recorded by: Steve Hall on 2019-05-25
Orange Co.
Comment:
Recorded by: Steve Hall on 2019-05-25
Orange Co.
Comment: Femur of leg I much shorter than body		Recorded by: Steve Hall on 2019-05-25
Orange Co.
Comment:
Recorded by: Steve Hall on 2019-05-25
Orange Co.
Comment: Male, based on emarginate anterior edge of genital operculum		Recorded by: Steve Hall on 2013-05-13
Moore Co.
Comment: