Diactis hedini, Shelley & Richart, 2014

Shelley, Rowland M. & Richart, Casey H., 2014, Tynommatidae, n. stat., a family of western North American millipeds: Hypotheses on origins and affinities; tribal elevations; rediagnoses of Diactis Loomis, 1937, and Florea and Caliactis, both Shelley, 1996; and description of D. hedini, n. sp. (Callipodida: Schizopetalidea), Insecta Mundi 2014 (340), pp. 1-19 : 5-7

Diactis hedini , new species Figures 1–4

Type specimens. M holotype and F paratype ( NCSM) collected by M. Hedin, 17 December 2005, 4 km (2.5 mi) N of Interstate Highway 8 along SR 79, 1.9 km (1.2 mi) NE Descanso Jct., NW side of Guatay

Mountain (32°51’16”N, 116°35’68”W), elevation 1,080 m (3,600 ft.), San Diego Co., California.

Diagnosis 50 rings including epiproct. Gonosternum with dactyliform, medial projection. Telopodal stem of subequal width throughout most of length, tapering apically to acuminate tip; prefemoral process short and broad, directed distolaterad. Distal processes arising subapically; tibiotarsus a broad continuation of telopodal stem curving opposite to solenomere branch; latter bending caudolaterad, process ‘B’ absent, apparently represented by prefemoral process ( Fig. 1–4 ).

Ecology. The types were retrieved from a berlesate of Coast Live Oak ( Quercus agrifolia Nee ) litter adjacent to Samagatuma Creek in a Western Sycamore ( Platanus racemosa Nutt. ) riparian corridor forest that runs through coastal sage and chaparral habitat. This is the southernmost US locality for the salamander, Ensatina eschscholtzii klauberi Dunn, 1929 , and investigating other localities where it is known (e.g., Sierra San Pedro Martir, Baja California Norte, Mexico) may provide more diactidine callipodidans and perhaps even D. hedini .

Etymology. We are pleased to name this species for Dr. Hedin, who graciously allowed RMS to search through his collection, take samples of interest, and add them to the invertebrate research holdings at the NCSM. The types of this species are deposited in the primary type collection.

Distribution. Known only from the type locality, in the Cleveland Nat. For., southcentral San Diego Co., near the center of the generic range. The site is also the community of Guatay, approximately 40 km (25 mi) east of downtown San Diego.

Remarks. Diactis hedini belongs to the “ D. triangula species group” with D. triangula and D. frondifera . While differences exist in the distal telopodal configurations and branches, the major distinction between the components is the position of the third projection, subbasal and a true “prefemoral process” in D. hedini and shorter and progressively more distal in D. frondifera and D. triangula , hence labeled process ‘B’ ( Fig. 5–6 ). Though longer in D. hedini , the projections seem to represent the same structure in all species; its telopodal position is what changes. Consequently, D. hedini clarifies process ‘B’, whose apparent identity was not evident when D. triangula and D. frondifera were the only group components.

Figures

Figures 1-6. Diactis spp. 1) D. hedini holotype, right gonopod, caudal view. 2) D. hedini holotype, right gonopod, telopodite of the same, medial view. 3) D. hedini holotype, right gonopod, the same, lateral view. 4) D. hedini holotype, right gonopod, distal extremity of the same, anterior view. 5) Telopodite of right gonopod of D. frondifera male from Los Angeles Co., California, lateral view. 6) Telopodite of right gonopod of D. triangula male from San Bernardino Co., California, anterior view. A, process ‘A’; B, process ‘B’; pfp, prefemoral process; s, solenomere; sb, solenomere branch; tt, tibiotarsus.