Austrotyla stephensoni, Shear, William A. & Steinmann, David B., 2013

Shear, William A. & Steinmann, David B., 2013, Cave millipedes of the United States. XIII. A new, troglobiotic species of Austrotyla from Colorado (Diplopoda, Chordeumatida, Conotylidae), Zootaxa 3745 (4), pp. 486-490 : 488-490

Austrotyla stephensoni , n. sp.

Figs. 2 , 7–10

Type. Male holotype from Bonnie’s Hall Cave, 9200’ (2804 m) asl, N39°29.3’ W106°39.5’, Eagle Co., Colorado, White River National Forest, collected 8 October 2012 by David Steinmann, deposited in Denver Museum of Nature & Science, Denver, Colorado.

Diagnosis. Austrotyla stephensoni differs from every other species of Austrotyla in the notched, or bifid, coxites of the posterior gonopods ( Fig. 10 ). From A. coloradensis it further differs in the markedly reduced posterior lobe of the anterior gonopods (cf. Figs. 5, 6 ) and the form of the fimbriate branches, which are larger and more strongly curved, and in having fewer ocelli, proportionally longer legs and antennae, and being depigmented (troglobiotic syndrome). In addition, the femoral knobs of the male third and fourth legs of coloradensis are distal, while in stephensoni they are mesal (cf. Figs. 3, 4, 7, 8 ).

Etymology. The species epithet honors Jeff Stephenson, who has helped with hundreds of cave life specimens including many new species, and who is very supportive of cave life research as Collections Manager for the Zoology Department at the Denver Museum of Nature & Science.

Description. Male holotype: Length, 14.0 mm, greatest width 0.9 mm; head and anterior end lightly mottled purplish tan, otherwise unpigmented ( Fig. 2 ). About 17 ocelli in triangular eyepatch, ocelli unpigmented, irregularly shaped, dorsal row lacking clearly formed lenses. Antennae elongate, extending back to fourth diplosegment if fully extended. Legpairs 3, 4 ( Fig. 7, 8 ) crassate, femora and prefemora swollen and mesally curved; both with prominent ventral apophysis slightly distal of midlength on femora. Anterior gonopods ( Fig. 9 ) with distinct sternum bearing curved, mesally directed fimbriate branches. Basal angiocoxite branches narrow, distally toothed; coxal plates large, deeply cupped, basolaterally with translucent oval “window” bordered laterally by sternal process. Posterior gonopods ( Fig. 10 ) with coxites strongly curved, cupped anteriorly, with deep mesal notch in each coxite producing bifid appearance in ventral view; basal fimbriate area reduced; prefemora with deep lateral notches, distal articles short, slightly longer than prefemora.

Notes. The type locality, Bonnie’s Hall, is a cave located at the bottom of a moss-covered sinkhole formed in Leadville Limestone. The total surveyed length of Bonnie’s Hall is 273’ (83.2 m) (Reames, 2011). The temperature inside the cave is 1° C, just above freezing, with humidity at 94%. Numerous other macroinvertebrate species live in the cave including springtails, harvestmen, diplurans, spiders, flies, beetles and mites. Bats were observed on the cave ceiling. There are other limestone caves near Bonnie’s Hall which may also harbor populations of A. stephensoni .

Acknowledgments

We would like to thank Kay Hopkins, Rich Doak, Richard Haskins, Bill Kight, Phil Nyland and Scott Fitzsimmons with the White River National Forest, United States Forest Service, for helping with the Special Use Permit under which the specimens were collected. WS is grateful to Jeff Stephenson and Frank Krell of the Denver Museum of Nature & Science for loaning the specimens. The cavers involved in the discovery and mapping of Bonnie’s Hall are thanked for their contributions, including Ed Crawford, Bob Ayre, Richard Klatt, Gene Dover, Paul Burger and Mark McVay. Debbie and Nathan Steinmann assisted with invertebrate collecting in the cave. The publication of this research was made possible under a grant (NSF DEB-1256139) to WS, Jason Bond, Petra Sierwald and Paul Marek, and with assistance from the Professional Development Committee of Hampden-Sydney College.

Literature cited

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Figures

FIGURES 1, 2. Field appearance of Austrotyla millipedes. Fig. 1. Austrotyla coloradensis, penult male. Fig. 2. Austrotyla stephensoni, mature male. Photograph by David Steinmann.

FIGURES 3 – 10. Structures of male Austrotyla millipedes. Figs. 3 – 6. Austrotyla coloradensis. Fig. 3. Right third leg, posterior view. Fig. 4. Right fourth leg, posterior view. Fig. 5. Anterior gonopods, posterior view. Fig. 6. Posterior gonopods, anterior view. Figs. 7 – 10. Austrotyla stephensoni. Fig. 7. Right third leg, posterior view. Fig 8. Right fourth leg, posterior view. Fig. 9. Anterior gonopods, posterior view. Fig. 10. Posterior gonopods, anterior view.