Schoettella glasgowi ( Folsom, 1916 )

Bernard, Ernest C., 2015, Redescriptions of Hypogastruridae and Onychiuridae (Collembola) described by David L. Wray, Zootaxa 3918 (3), pp. 301-338 : 321-323

Schoettella glasgowi ( Folsom, 1916)

Figs. 13–15

Achorutes (Schöttella) glasgowi Folsom 1916: 494 .

Achorutes magnoliana Wray 1952: 98 junior synonym

Hypogastrura (Schoettella) glasgowi Christiansen & Bellinger 1980: 190 ; 1998: 198.

Specimens examined. One specimen of S. glasgowi (labeled “cotype”), sex undetermined, head lost during mounting process, New York, Blauvelt, 17 March 1914; female of A. magnoliana (labeled “ type ”), Illinois, Magnolia, Starved Rock State Park, 24 May 1944, ground cover, H. H. Ross, coll.; 3 specimens, sex not determined, Illinois, Williamson County, Devil’s Kitchen Lake Wood, 3 November 1973, J. A. Cancellare, coll.; 1 juvenile specimen, North Carolina, Swain County, Great Smoky Mountains National Park, Ravensford, south of Big Cove Road, moss on stream bank, 27 October 2000, E. C. & D. A. Bernard, colls.

Characters of S. glasgowi type material. Body length 1.0 mm, deep violet-blue with scattered pale spots ( Fig. 13 A). Head lost during mounting process. Chaetotaxy obscure, most setae transparent or missing. Inner edge of unguis with single tooth at about 60% of the distance from ungual base, outer edge without teeth; unguiculus minute, pointed; each tibiotarsus with two clavate tenent hairs ( Fig. 13 B). All parts of furcula distinct ( Fig. 13 C); dens with four setae, outer proximal seta longer than others; mucro nearly as long as dens, tapering to rounded tip, granulated basal lamella slightly more than half mucro length. Anal spines minute.

Redescription based on A. magnoliana type material and other specimens. Length 0.6‒0.7 mm [Background color yellow, splotched and heavily specked with dark purplish pigment.] Eye patches black, 8+8 ocelli. Granulation moderately fine, diameter of granules 2.3–3.2 Μm; Yosii’s ‘a’ number not determined. Head and body setae short, uniform; setae of Abd. V and VI slightly longer than on rest of body ( Figs. 14 A, B), sparsely serrate ( Fig. 14 D). Sensillum-like setae about twice the length of neighboring p-setae. Pronotum with 2+2 setae of equal length. Head with 4 sd-setae, sd4 or sd5 missing; d1 occasionally absent. Mesonotum and metanotum lacking setae a4, m2, m5, and p5; a2 and m1 often missing; seta m4 anterior to m3, m4’ present ( Figs. 14 A, B). Abdominal segments I–III lacking setae a2, presence of a3 and a4 variable; m-rows consisting of seta m3. Abdominal segment IV with a1–3, m4, and all p-setae; Abd. V lacking seta p2. Subcoxae I, II, III with 1, 2, 3 setae, respectively. Plurichaetosis present as thoracic m4’ setae.

Antennal segments III and IV not clearly demarcated. Segment IV with granulated, unlobed apical vesicle, tapering, pointed organite, and exposed microsensillum ( Fig. 15 G); dorsally and laterally with 13 sensillum-like setae not clearly differentiated into sensilla and sensilliform setae ( Figs. 15 F, G); dorsally with socketless apical pin seta, ventrally with two apically hooked sensilliform setae; other setae typically setiform; ventral sensory field poorly differentiated, represented by a few shorter typical setae ( Fig. 15 G). Sense organ of Ant. III with two slightly clavate sensilla in shallow groove, flanked by long guard sensilla; microsensillum peg-like, in distinct depression ( Fig. 15 H). First antennal segment with 7 setae, Ant. II with 12 setae.

Ocelli 8+8, on dark patches. Postantennal organ rounded without distinct lobes ( Fig. 15 B), with four weak lobes ( Fig. 15 A), or with four small but distinct lobes ( Fig. 15 C), smaller than or equal to width of nearest ocelli. Labrum ( Fig. 14 E) with rounded margin, six large but weak distal protuberances, basal two-thirds granulate, apical third smooth; setal formula 5-5-4. Maxilla head ( Fig. 14 C) with long, broad lamella 1 extending well past capitulum teeth, fringe long on one edge, short on other edge; lamella 2 nearly as long as lamella 1, distal half on one side with dense row of lobed teeth, medially with triangular ciliate field; lamella 3 minute, pyriform; lamella 4 reaching to base of capitulum teeth, apex round, ciliated; lamella 5 shorter than 4, surface covered with minute denticles; lamella 6 stalked, with oval distal surface sparsely ornamented with denticles. Labial palpus ( Fig. 15 D) with sensilla A–E present and longer than all guard setae except e1. Guard setae d1, e2, e3, e6 and e7 absent; a1, b1 and b2 granulate, papilliform; lateral papilla minute, rounded-conical; remaining guard setae slender, rounded at tips. Labial palpus with 6 proximal setae; basolateral and basomedian fields each with 4 setae.

Tibiotarsi I, II, III with 19, 19, 18 setae, respectively; two long, strong, clavate tenent hairs reaching tip of unguis; each unguis with distinct distal inner tooth about two-thirds the distance from ungual base; lateral teeth not observed ( Figs. 13 B, 15I, J). Unguiculus present, minute, tapering to pointed apex.

Ventral tube with 4+4 setae. Furcula ( Figs. 13 C, 14K) well-developed, all parts distinctly separated. Manubrium with 9+9 dorsal setae, one proximal seta more than twice the length of the others; dens smooth with 4 setae, outer proximal seta longer than others; each dens with weak ventro-apical swelling; mucro slender, tapering, nearly as long as dens, with narrow granulated basal lamella slightly less to slightly more than half the mucro length. Anal spines minute, pointed, about one-fifth length of inner unguis.

Remarks. Four slides labeled A. magnoliana “ type series” each contained one specimen of Xenylla welchi Folsom 1916 ; these X. welchi specimens apparently did not contribute to Wray’s A. magnoliana description. A fifth slide labeled “ type ” contained one Schoettella specimen. Christiansen & Bellinger (1980, 1998) were not able to study type material of A. magnoliana , but based on structure and chaetotaxy of the furcula, minute anal spines, and presence of two tenent hairs, placed A. magnoliana in synonymy with S. glasgowi ( Folsom, 1916) . Schoettella glasgowi was described as having ungues with a pair of lateral teeth but lacking an inner tooth, whereas the type specimen of S. magnoliana as redescribed here lacks lateral teeth but possesses an inner tooth on the unguis. Although most features of the S. glasgowi type specimen were obscure, the unguis lacked lateral teeth but possessed an inner tooth more than half the distance to the ungual tip, similar to the unguis of S. magnoliana . The dens and mucro of the two taxa appear identical. Therefore, S. magnoliana is affirmed as a junior synonym of S. glasgowi .

Figures

FIGURE 13. Schoettella glasgowi. A) Dorsal habitus, scale 500 Μm. B) Front foot complex, scale 10 Μm. C) Dens and mucro, scale 25 Μm.

FIGURE 14. Schoettella glasgowi. A) Dorsal chaetotaxy, “ type ” of Achorutes magnoliana. B) Dorsal chaetotaxy, specimen from Swain County, North Carolina. C) Head of maxilla, Williamson County, Illinois. D) Typical cephalic setae, A. magnoliana “ type ”. E) Labrum, specimen from Williamson County, Illinois.

FIGURE 15. Schoettella glasgowi. A) Postantennal organ (PAO) and anterior eyes, right side, Achorutes magnoliana “ type ”. B) PAO and anterior eyes, left side, specimen from Swain County, North Carolina. C) PAO and eyes, left and right sides, specimen from Williamson County, Illinois. D) Labial palpus, A. magnoliana lectotype. E) Ventral side of head, A. magnoliana lectotype. F) Fourth antennal segment, subdorsal view; arrow indicates socketless “ pin ” seta. G) Apex of fourth antennal segment, subventral view. H) Sense organ of third antennal segment. I) Hind tibiotarsus, specimen from Williamson County, Illinois. J) Fore tibiotarsus, A. magnoliana lectotype. K) Furcula, A. magnoliana lectotype.