Brachoria electa, CAUSEY, 1955

Marek, Paul E., 2010, A revision of the Appalachian millipede genus Brachoria Chamberlin, 1939 (Polydesmida: Xystodesmidae: Apheloriini), Zoological Journal of the Linnean Society 159 (4), pp. 817-889 : 843-844

BRACHORIA ELECTA CAUSEY, 1955

‘THE KENTUCKY RIVER MIMIC MILLIPEDE’

( FIG. 13A–D, FIG . 40A) Brachoria electa Causey, 1955: 25 . Keeton, 1959: 20. The close similarities mentioned by Keeton (1959) between B. electa and B. ochra do not appear to be synapomorphic. Instead, B. electa is more closely related to B. divicuma than it is to B. ochra , and does not warrant subspecific status of the latter.

Diagnosis: Adult males of B. electa are distinct from other Brachoria species based on the combination of: Colour. Striped ( Fig. 40A), yellow (2.5Y 8.5/8) metatergal stripes, anterior collum spot, legs (2.5Y 8/12). Exoskeleton. Caudolateral corners, paranota 1–4 rounded, lateral margins angled cephalically. Gonopods. Gonopodal acropodite narrow, half width of tibia on leg pair 9, of uniform width throughout. Prefemur with thin, sharp prefemoral process. Acropodite not bent medially, projecting straight from prefemur. Cingulum well defined, deep ( Fig. 13C , arrow). Acropodite bent at cingulum cephalically 45°. Arc immediately distal beyond cingulum slightly elbowed. Acropodal apex projecting laterally. Arc projecting straight, not curved, anterolaterally. Acropodal apex bent 90°, with recurved zig-zag apex ( Fig. 13B ). Note: B. electa is similar in appearance to B. cedra in gonopodal form. However, the acropodite of B. electa projects straight from the prefemur ( Fig. 13A ), whereas in B. cedra it is curved out in a C-shaped form ( Fig. 8A ). The apex of B. electa has a distinct recurved zig-zag apex ( Fig. 13B ), where in B. cedra the apex is simpler and not zig-zagged ( Fig. 8B ).

Variation: Brachoria electa is known only from the type locality in Tyrone, Kentucky and one locality in Mercer County. There is some variation in coloration amongst these specimens with one less frequent variant of the common striped morph: small yellow metatergal spots, in addition to the metatergal stripes. Measurements : ♂ (N = 4) BL = 38.27–38.58 (38.43/0.22). CW = 7.00–7.48 (7.25/0.20). IW = 4.41– 5.00 (4.71/0.25). ISW = 1.28–1.52 (1.38/0.10). B10W = 8.69–9.91 (9.35/0.50). B10H = 5.20–6.10 (5.61/0.38). ♀ (N = 3) BL = 38.18–40.25 (38.97/1.12). CW = 7.55–7.75 (7.65/0.10). IW = 5.49–5.60 (5.56/ 0.06). ISW = 1.60–1.70 (1.63/0.06). B10W = 10.33– 10.80 (10.51/0.26). B10H = 6.70–7.50 (7.03/0.42) .

Description: Male described by Causey (1955); redescribed by Keeton (1959).

Ecology: Brachoria electa specimens were collected during the day (13:00) from a maple, birch, oak, and tulip poplar forest. Individuals were found in the small valley of Wildcat Creek, which runs into the Kentucky River. One other xystodesmid encountered sympatrically at this locality is A. v. corrugata , which appears similar in coloration with B. electa . Note: individuals of B. electa may easily be confused in the field with A. v. corrugata because of similarity in colour patterns, but can be distinguished by the presence of the following characters (viewed with a 20¥ loupe): Acropodite with midlength transverse groove, cingulum. Acropodite not circular as in A. v. corrugata . Acropodite projecting straight from the prefemur, whereas in A. v. corrugata it is strongly curved out in a circular coil. (Although B. calceata and B. electa were both recorded from Tyrone, I have never found them together. It is likely that they co-occur; however, they may have different ecological requirements that preclude them from sharing the same habitat.)

Distribution: Known only from the type locality and one place, 23.76 km south-east in Mercer County, Kentucky, both of which are very close to the Kentucky River. The closest known Brachoria species , B. calceata , co-occurs with B. electa at their type localities.

Material examined: Type specimens. ♂ holotype ( AMNH) from Anderson County, Kentucky, Tyrone, 28.iv.1892 (coll: H. Garman) (vidi). Nontype specimens. Kentucky: 2♂ (SPC000613*: EU127860 , SPC000617), 3♀ (SPC000618, 19, 23), Anderson County , Tyrone , KY-1510, about 4 rd km south-southeast of junction with US-62, Wildcat Creek (38.02163°N, - 84.83765°W, 184 m), 26.vi.2005, 13:00 (coll: P. Marek). 1♂ ( PMLN0019 ), Mercer County , Kentucky River bluff, 1.6 km north-east of Shakertown (37.8269°N, - 84.7254°W, 259 m), 1.v.1954 (coll: L. Hubricht) .

BRACHORIA ENODICUMA KEETON, 1965

Figures

Figure 8. Brachoria cedra Keeton, 1959. A–D, holotype specimen gonopods: A, left male gonopod, anterior view; B, left male acropodal apex, ventrolateral view; C, left male gonopod, medial; D. same, posterior (acropodite length = 1.59 mm).

Figure 13. Brachoria electa Causey, 1955. A–D, holotype specimen gonopods: A, left male gonopod, anterior view; B, left male acropodal apex, magnified; C, left male gonopod, medial; D, same, posterior (acropodite length = 1.67 mm).