Eutyphlus dybasi Park, 1956
publication ID |
https://doi.org/ 10.1649/072.070.0102 |
persistent identifier |
https://treatment.plazi.org/id/038FA12D-FFAA-5809-FE9C-3FB9FEE1FCD0 |
treatment provided by |
Diego |
scientific name |
Eutyphlus dybasi Park, 1956 |
status |
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1. Eutyphlus dybasi Park, 1956 View in CoL ( Figs. 3, 4 View Figs , 13 View Figs , 19A, B View Figs , 28 View Figs )
Diagnosis. Eutyphlus dybasi differs from all known Eutyphlus species , except for E. spiralis , in lacking the anteroprosternal foveae, the presence of secondary sexual modifications on the legs of males ( Fig. 19 View Figs ), the quadrifoveate elytra, and concave metaventrite of both sexes, along with the larger, broadly ovate seventh ventrite of males and the large, concave, triangular seventh ventrite of females. The aedeagus is larger than that of other species in the genus, with the exception of E. spiralis , and differs in structure, bearing an enlarged dorsal lobe, a left paramere bearing distal ctenidia, a median lobe with an extensive fimbriated process, and a flattened, ventral right paramere ( Fig. 13 View Figs ).
Eutyphlus dybasi is most similar to E. spiralis and can be separated by differences in the morphology of the aedeagus. In E. dybasi , a brush of ctenidial spines occurs on the left, dorsally located paramere, and the distal expansion of the right, ventrally located paramere curves towards the right; the left paramere is spiralshaped, and the right paramere curves towards the left in E. spiralis .
Redescription. MALE. Measurements: HL 0.20 mm, HW 0.29 mm; PL 0.34 mm, PW 0.32 mm; EL 0.55 mm, EW 0.55 mm; A1-6 respectively 0.02, 0.15, 0.15, 0.11, 0.11, 0.3 mm; An1–11 respectively 0.09, 0.05, 0.03, 0.02, 0.02, 0.02, 0.03, 0.03, 0.04, 0.04, 0.10 mm; MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. GL 0.22 mm, GW 0.14 mm. ML 1.62 mm. Integument: Typical for genus. Head: Slightly narrower than pronotum. Tempora evenly rounded. Eyes present and well-developed with 35 facets, slightly emarginate posteriorly, ocular canthus weakly developed, projecting weakly laterally and sloping gently to gular area. Ventral surface of head flat, slightly rounded in gular area, gular sulcus well-developed anteriorly and projecting to margin of posteriorly located, paired, gular foveae. Thorax: Prothorax with basolateral margin slightly crenulate, median longitudinal sulcus present, area behind basal sulcus with thin longitudinal sulcus extending from basal bead to basal sulcus. Prosternum lacking anteroprosternal foveae. Mesotrochanter bearing tubercle, mesotibia with blunt apical spine. Metaventrite slightly concave baso-medially. Metatrochanter with tubercle. Elytra bearing 3 basal foveae as well as subhumeral foveae. Flight wings well-developed. Abdomen: Tergites unmodified. Seventh ventrite broadly oval, other ventrites unmodified. Genitalia: Aedeagus asymmetrical. Dorsal lobe broad, membranous. Left paramere expanded distally, bearing brush of ctenidial spines. Median lobe with distally fimbriated process. Right paramere more ventral, flattened, distally expanded towards right, with apical patch of scattered, flattened setae.
FEMALE. Measurements: HL 0.25 mm, HW 0.30 mm; PL 0.38 mm, PW 0.32 mm; EL 0.50 mm, EW 0.60 mm; A1-6 respectively 0.03, 0.17, 0.15, 0.15, 0.13, 0.05 mm. An1–11 respectively 0.09, 0.05, 0.03, 0.02, 0.02, 0.02, 0.03, 0.03, 0.04, 0.04, 0.10 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. GL 0.15 mm, GW 0.21. ML 1.7 mm. Integument, head, thorax, and abdomen: Similar to male except eyes smaller with 12 facets, legs unmodified, 7 th abdominal ventrite slightly concave, broadly triangular. Genitalia: Membranous, narrowed towards distal end. Internally sclerotized portion forked at base and fused at 1/3 length.
Variation. Considerable variation occurs among males with respect to the presence of secondary sexual characters on the legs, ranging from no
17) E. spiralis ; 18) E. thoracicus . AP = accessory process; LP = left paramere; ML = median lobe; RP = right paramere.
modifications to possessing the full spectrum of modifications present within the species ( Fig. 19 View Figs ). These characters are variable within populations, sometimes among individuals from the same collection event and apparently not linked with differences in locality or habitat. No differences in genitalia correlated with these variations were observed.
Within the genus, the eyes of E. dybasi females are larger and more convex. The genitalia of females vary in the degree of sclerotization of the internal y-shaped process, possibly as an artifact of clearing and preparation.
Bionomics. Biological information on E. dybasi in the literature is limited to locality data in the original description ( Park 1956) and a study of leaf litter Coleoptera of Great Smoky Mountains National Park ( Ferro et al. 2012b). The following information was obtained from data on collection labels of 99 specimens. Seasonality: Eutyphlus dybasi has been collected during late spring through winter (earliest date 21 March; latest 18 December). Elevation: The majority of individuals were collected at 620–1,800 m elevation. However, several individuals were collected from an elevation of 2,750m. Habitat/Microhabitat: Substrates at collection sites were mixed forest and hardwood litter. Specific woody plant cover mentioned included oak, Rhododendron , tulip tree, and alder. Collecting methods: Most specimens were collected by litter sifting and extraction using a Berlese funnel. However, E. dybasi was the only species of Eutyphlus collected by both Malaise traps and pitfall traps.
Distribution. Eutyphlus dybasi is known from Georgia (Union County), North Carolina (Macon and Swain Counties), and Tennessee (Blount, Cocke, and Sevier Counties) ( Fig. 28 View Figs ).
2. Eutyphlus prominens Casey, 1894 ( Figs. 5, 6 View Figs , 14 View Figs , 20–25 View Figs , 29 View Figs )
Diagnosis. Eutyphlus prominens may be distinguished from all known Eutyphlus species by the combination of a lateral excavation and vertical
30) E. schmitti ; 31) E. similis ; 32) E. spiralis ; 33) E. thoracicus .
lamina on the third male ventrite and an excavated fourth male ventrite ( Figs. 20–25 View Figs ). The aedeagus bears a large, membranous projection associated broadly with the fimbriated median lobe and three distal setae on the single ventrally located paramere ( Fig. 14 View Figs ).
Redescription. MALE. Measurements: HL 0.20 mm, HW 0.25 mm; PL 0.30 mm, PW 0.29 mm; EL 0.40 mm, EW 0.42 mm; A1–6 respectively 0.02, 0.14, 0.11, 0.10, 0.10, 0.02 mm. An1–11 respectively 0.08, 0.06, 0.03, 0.03, 0.02, 0.02, 0.02, 0.03, 0.04, 0.04, 0.11 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. GL 0.06 mm, GW 0.04 mm. ML 1.53 mm. Integument: Typical for genus. Head: Slightly narrower than pronotum. Eyes present and well-developed, bearing 25 facets, convex, longer than wide, ocular canthus weakly developed, projecting laterally and sloping gently to gular area. Ventral surface of head slightly rounded in gular area, gular sulcus developed anteriorly and projecting to margin of posteriorly located, paired, gular foveae. Thorax: Pronotum with margin slightly crenulate, median longitudinal sulcus present, area behind basal sulcus bearing small, median longitudinal carina that extends into and bisects sulcus. Prosternum bearing anteroprosternal foveae. Paired, median mesoventral foveae present. Metaventrite convex. Elytron bearing 2 closely approximate basal foveae, as well as subhumeral foveae. Flight wings well-developed. Abdomen: First visible abdominal tergite with oval depression wide (at least ¾ segment length); other tergites unmodified. Second ventrite with longitudinal carina interrupted medially. Third ventrite modified with shelf-like excavation laterally, setose lamina produced vertically in median of excavation, sclerotized shelf produced over excavation bearing fringe of setae projecting laterally. Fourth ventrite excavated in lateral 1/3, excavation unmodified. Seventh ventrite small and strap-like. Other ventrites unmodified. Genitalia: Aedeagus complex and asymmetrical. Left paramere more dorsal, comprising an oblique, sclerotized bar. Associated process immediately beneath, sclerotized, bearing 2 erect setae. Median lobe modified into internal, fimbriated process associated with extensive, membranous projection. Right paramere more ventral, bearing 3 distal setae.
FEMALE. Measurements: HL 0.15 mm, HW 0.25 mm; PL 0.28 mm, PW 0.28 mm; EL 0.40 mm, EW 0.41 mm; A1–6 respectively 0.03, 0.15, 0.11, 0.10, 0.10, 0.02 mm. An1–11 respectively 0.08, 0.05, 0.03, 0.02, 0.02, 0.02, 0.02, 0.03, 0.03, 0.04, 0.11 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. ML 1.32 mm. Integument, head, thorax, and abdomen: Similar to male except eyes greatly reduced to 2 facets, ocular canthus well-developed. Tempora rounded and broad. Pronotum more quadrate. Third and fourth ventrites unmodified. Seventh ventrite small and transverse. Genitalia: Membranous, completely lacking sclerotization. Produced into voluminous median structure and billowy right sac.
Variation. The size and shape of the eyes vary in male E. prominens , and the elytra vary from being bi- to trifoveate. Major intraspecific variation occurs in male secondary sexual characters. Specifically, the sclerotized shelf of the third ventrite that overhangs the lateral excavation on this segment ranges from a small, crescent-shaped projection to an expanded shelf that extends posteriorly over part of the excavation of the fourth ventrite. In addition, the vertical lamina of the excavation on the third ventrite and the degree of excavation of the fourth ventrite are produced to varying degrees. Examination of 27 males, including at least one male from each of the 22 localities, resulted in identification of six distinct “ types ” of ventrite modifications in E. prominens ( Figs. 20–25 View Figs ), with a range of more subtle variations observed within each type. Type II ( Fig. 21 View Figs ) was observed most frequently, with 16 of the 27 males possessing characters that fell into this category. When multiple individuals were observed from a single locality, most exhibited the same form. However , two specimens collected from the same locality in Caldwell County, North Carolina were found to exhibit different forms .
Slight variations were observed in the aedeagus of E. prominens . The number of setae on the ventral paramere varies from three to four. Most possess three, but some individuals have a fourth offset slightly from the three main setae that are shorter and narrower in form. The degree of extension of the inflated membranous projection varies among individuals. This process is a component of the median lobe of the aedeagus and likely functions as the intromittent organ during mating. The apparent differences in inflation may be related to specimen preparation.
Female E. prominens specimens exhibit variations in eye facet number and the shape of the ocular canthus, but are otherwise similar.
Bionomics. No previously published information exists dealing with the biology of E. prominens . Seasonality: Specimens were collected during early spring and early winter (earliest date 6 February; latest 11 November). The two-month gap likely reflects lack of collecting events. Elevation: Most specimens were collected from elevations between 430 and 1,520 m. Habitat/Microhabitat: Most specimens were associated with heavily decayed and rotting wood, either in litter near wood or in wood. Collecting methods: Most specimens were collected using sifting and Berlese funnel extraction, with a small number obtained using flight intercept traps.
Distribution. Eutyphlus prominens is known from Georgia (Rabun County), North Carolina (Buncombe, Caldwell, Haywood, Macon, and Yancy Counties), South Carolina (Oconee County), Tennessee (Blount, Cocke, Sevier, Unicoi Counties), Virginia (Smythe County), and West Virginia (Pocahontas County) ( Fig. 29 View Figs ).
3. Eutyphlus schmitti Raffray, 1904 ( Figs. 7, 8 View Figs , 15 View Figs , 27 View Figs , 30 View Figs )
Diagnosis. Eutyphlus schmitti differs from all known Eutyphlus species by the structure of the male ventrites. The apical margin of the second ventrite is excavated, the third is excavated laterally with vertical lamina and median plates that overlap the fourth, and the fourth and fifth are excavated laterally ( Fig. 27 View Figs ). The aedeagus bears a process on either side of the parameres, and the median lobe is modified into a fimbriated, sclerotized process ( Fig. 15 View Figs ).
Redescription. MALE. Measurements: HL 0.21 mm, HW 0.25 mm; PL 0.27 mm, PW 0.26 mm; EL 0.43 mm, EW 0.51 mm; A1–6 respectively 0.04, 0.11, 0.11, 0.11, 0.09, 0.03 mm. An1–11 respectively 0.07, 0.05, 0.04, 0.03, 0.02, 0.02, 0.02, 0.04, 0.04, 0.05, 0.14 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. GL 0.08 mm, GW 0.05 mm. ML 1.44 mm. Integument: Typical for genus. Capitate genal setae sparse. Head: About as wide as pronotum. Eyes small, with 12 facets, weakly convex, longer than wide, ocular canthus weakly developed, projecting laterally and sloping gently to gula. Ventral surface of head rounded at gula, gular sulcus developed weakly anteriorly and projecting to margin of posteriorly located, paired, gular foveae. Thorax: Pronotum with lateral margin crenulate, median longitudinal sulcus present, area behind basal sulcus bearing small, median longitudinal carina that extends into and bisects sulcus. Prosternum bearing anteroprosternal foveae. Paired, median mesoventral fovea present. Mesotrochanters bearing single, median spine. Metaventrite concave baso-medially. Elytra bearing 2, closely approximate basal foveae, as well as subhumeral and sutural foveae. Flight wings well-developed. Abdomen: Tergites unmodified. Second ventrite with apical margin excavated laterally to receive vertical lamina of 3 rd ventrite. Third ventrite excavate laterally, bearing lamina with numerous setae, median portion of sclerites with sclerotized plates bearing fringes of setae that extend over excavation and slightly over margin of 4 th ventrite. Fourth ventrite excavated laterally, middle portion of sclerites contiguous with 2 lateral, sclerotized projections that overhang excavated portion of 5 th ventrite. Fifth ventrite laterally excavated to about ⅔ length of segment. Seventh ventrite small and elongate teardrop-shaped. Other ventrites unmodified. Genitalia: Aedeagus asymmetrical. Left paramere more dorsal, formed as oblique, sclerotized bar with numerous small setae and a large seta about middle, distal end flattened and slightly twisted to expose ventral face. Process associated with paramere branching ventrally to left, similar in form to paramere. Median lobe comprising internal, sclerotized process bearing 2 distinct arms, left arm bearing numerous spicules and spines and right arm more membranous, bearing longer projections. Process associated with right paramere sclerotized, slightly narrowed and curved towards distal end. Right paramere more ventral, flattened and bearing 3 enlarged, thickened distal setae.
FEMALE. Measurements: HL 0.20 mm, HW 0.30 mm; PL 0.30 mm, PW 0.30 mm; EL 0.41 mm, EW 0.50 mm; A1–6 respectively 0.03, 0.14, 0.14, 0.13, 0.12, 0.05 mm. An1–11 respectively 0.07, 0.06, 0.02, 0.01, 0.01, 0.01, 0.02, 0.02, 0.04, 0.03, 0.10 mm. MP 1–4 respectively 0.01, 0.04, 0.01, 0.04 mm. MP 1.73 mm. Integument, head, thorax, and abdomen: Similar to male except eyes greatly reduced, comprising 2 facets, ocular canthus well-developed. Tempora rounded and broad. Pronotal margin barely crenulate, basal sulcus on pronotum straight between basal foveae. Lacking abdominal secondary sexual characters. Seventh ventrite small and transverse. Genitalia: Membranous, completely lacking sclerotization. Produced into slightly elongate median structure and billowy right sac.
Variation. Slight variation was observed in the shape and size of the sclerotized plates and excavated portions of the male ventrites ( Fig. 27 View Figs ). This variation was less extreme than those noted for E. prominens . Among females, the number of eye facets varied 1–6. Length of the hind margin of the prothorax posterior to the basal sulcus was slightly different among individuals. The depth and angle of this sulcus was slightly variable as well, but never attaining the same angle as in E. prominens or E. similis .
Bionomics. Seasonality: E. schmitti was collected from late spring through late fall/early winter (earliest date 16 May; latest 11 November). Based on the data available, occurrence of adults in this species is somewhat more seasonal than it is for other species, though this may be an artifact of sampling. Elevation: Two elevations were included in the label data from the available material: 274 m and 914 m, somewhat lower than most other species in the genus, but the data is limited. Habitat/ Microhabitat: Specimens were collected from forest hardwood leaf litter, Rhododendron litter, beech litter, oak litter, and birch litter. Specimens were also found in Sphagnum moss. This species was represented in the study of an old growth forest habitat (“The Bowl”) in New Hampshire ( Chandler 1987). Collecting methods: Sifting and processing by Berlese funnels was the only collection method mentioned for this species.
Distribution. Eutyphlus schmitti is known from New Hampshire (Carroll, Coos, and Grafton Counties), New York (Cattaraugus County), Ohio (Highland County), Pennsylvania (Elk, Huntington, Jefferson, McKean, Somerset, and Westmoreland Counties), and West Virginia (Pocahontas County) ( Fig. 30 View Figs ).
4. Eutyphlus similis LeConte, 1880 ( Figs. 1, 2 View Figs , 9, 10 View Figs , 16 View Figs , 31 View Figs )
Diagnosis. Eutyphlus similis differs from all known Eutyphlus species in the form of the seventh ventrite of males (small and strap-like) ( Fig. 2 View Figs , VII), the absence of sexual modifications on ventrites of the males, and absence of flight wings in both sexes. The aedeagus is broadly egg-shaped with a rounded internal membrane associated with the distinctly forked, spinose median lobe, and the more ventral paramere bears four distal setae ( Fig. 16 View Figs ).
Redescription. MALE. Measurements: HL 0.24 mm, HW 0.28 mm; PL 0.31 mm, PW 0.30 mm; EL 0.41 mm, EW 0.50 mm; A1–6 respectively 0.03, 0.15, 0.12, 0.10, 0.10, 0.03 mm. An1–11 respectively 0.08, 0.05, 0.03, 0.03, 0.02, 0.02, 0.02, 0.03, 0.03, 0.04, 0.11 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. GL 0.08 mm long, GW 0.05 mm. ML 1.60 mm. Integument: Typical for genus. Capitate genal setae sparse. Head: About as wide as pronotum. Eyes small, with 12 facets, weakly convex, longer than wide, ocular canthus weakly developed, projecting laterally, and sloping gently to gular area. Ventral surface of head rounded in gular area, gular sulcus developed anteriorly and projecting to margin of posteriorly located, paired, gular foveae. Thorax: Pronotum with lateral margin barely crenulate, if at all. Median longitudinal sulcus present. Area behind basal sulcus bearing small, median longitudinal carina that extends into and bisects sulcus. Prosternum bearing anteroprosternal foveae. Paired, median mesoventral fovea present. Metaventrite strongly convex, more prominently so in apical ¼. Elytra bearing 2 basal foveae, subhumeral foveae present. Flight wings absent. Abdomen: Tergites unmodified. Fifth ventrite with lateral sides flattened, quadrate. Seventh ventrite small and strap-like. Other ventrites unmodified. Genitalia: Aedeagus asymmetrical. Left paramere dorsally attached, forming an oblique, sclerotized bar with distal end curved and slightly expanded, bearing 2 large, erect setae. Median lobe modified into internal, sclerotized process bearing 2 distinct arms with numerous spicules and spines, associated with inflated, membranous internal sac. Right paramere flattened, ventrally associated with phallobase and bearing four distal setae.
FEMALE. Measurements: HL 0.20 mm, HW 0.30 mm; PL 0.33 mm, PW 0.32 mm; EL 0.41 mm, EW 0.50 mm; A1–6 respectively 0.04, 0.15, 0.12, 0.11, 0.11, 0.03 mm. An1–11 respectively 0.08, 0.06, 0.03, 0.02, 0.02, 0.02, 0.02, 0.03, 0.04, 0.04, 0.12 mm. MP1–4 respectively 0.01, 0.05, 0.01, 0.05 mm. ML 1.74 mm. Integument, head, thorax, and abdomen: Similar to male except eyes greatly reduced, comprising a single facet (this exemplar; see variation comments below), ocular canthus well-developed. Tempora rounded and broad. Pronotum more quadrate. Metasternum more flattened and evenly rounded. Fifth ventrite not flattened laterally as in males. Seventh ventrite small and transverse. Genitalia: Membranous, completely lacking sclerotization. Produced into voluminous median membrane and billowy right sac.
Variations. The median longitudinal and antebasal pronotal sulci vary from relatively shallow to well-defined. The aedeagus varies slightly among individuals. The number of setae on the ventral paramere varies from three to six, with four the most common number. When more are present, they are shorter and/or narrower in form and set off slightly from the four main setae. The median membranous projection gives the aedeagus of E. similis its characteristic “eggshape.” It appears to vary in degree of inflation, but this may be an artifact of preparation.
Number of eye facets in females varies greatly from one to over 20, and the ocular canthus covaries in development.
Comments. Several collecting events produced over 40 females and fewer than 10 males. Other samples included only females, making the accurate identification of females important. However, the process of distinguishing E. similis females from the females of E. prominens is problematic and complicates efforts to determine accurate species placement from sites producing only females.
In his revision, Park (1956) suggested differences in head and pronotal widths as a reliable way to discriminate between females of the two species. To test this and to investigate other possible characters useful for identification, we measured body parts for 111 E. similis females and 13 E. prominens females. A single individual was taken from each locality represented in this study. Eutyphlus similis females exhibited a slightly wider range of sizes, but the two species overlapped broadly in these measurements ( Table 3). This overlap suggests that they cannot be distinguished based on visible characters, and association with males is the only way to identify females.
Bionomics. No previously published information on the biology of E. similis exists. Seasonality: The majority of E. similis specimens were collected during April, May, June, and July (earliest date 19 February; latest 6 December). Adults are probably present year-round, and at least one sample from snow- and ice-covered litter yielded specimens. Elevation: Specimens were collected from elevations between 460 m and 2,024 m. Habitat/Microhabitat: Specimens were collected from a wide range of forest litter habitats, including rotted leaves, oak litter, beech litter, Rhododendron , old-growth and non-old growth hardwood litter, and conifer litter (pine, spruce, and fir). The occurrence in conifer litter differs from the habitats that the other species are known from, but this may simply be due to the much larger sample size (approximately 700) for this species. This was the only Eutyphlus species collected from tree hole debris, gilled fungi, and cave litter. In a study of the Coleoptera community of the woody debris of Great Smoky Mountains National Park, a single male specimen of E. similis was collected from a dead-wood emergence chamber ( Ferro et al. 2012a). Collecting methods: Most individuals were collected by hand-collecting or sifting the substrate and then processing the material in a Berlese funnel. Some individuals were collected via flight intercept traps.
Distribution. This species is known from Arkansas (Washington County), Georgia (Dade and White Counties), Kentucky (Edmonson County and Mammoth Cave), Maryland (Calvary County), North Carolina (Avery, Buncombe, Caldwell, Haywood, Mecklenburg, Swain, Transylvania, Watauga, Wilkes, and Yancy Counties), Ohio (Fairfield and Lawrence Counties), Pennsylvania (Somerset and Westmoreland Counties), South Carolina (Greenville and Pickens Counties), Tennessee (Blount, Carter, Cocke, and Sevier Counties), Virginia (Giles, Madison, Page, Smythe, and Washington Counties) and West Virginia (Fayette, Mercer, and Pocahontas Counties) ( Fig. 31 View Figs ). The single Illinois record is a checklist record ( Chandler 1997) and requires confirmation.
The Washington Co., Arkansas record is unusual in that it is the only known locality west of the Mississippi River where any Eutyphlus specimens have been collected. Only E. similis females (16 individuals) are known from this locality, so the identification is considered provisional until additional specimens, including males, are found to confirm the identity of the species that lives in this disjunct area.
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