Speleochus Park, 1951

Carlton, Christopher E., 2012, First Records of Troglobitic Beetles from Arkansas: Two New Species ofSpeleochusPark (Coleoptera: Staphylinidae: Pselaphinae: Bythinini), and Synonymy ofSubterrochusPark withSpeleochus, The Coleopterists Bulletin 66 (3), pp. 177-186 : 179-185

Speleochus Park, 1951

Speleochus Park 1951: 46 (as subgenus of Machaerites ). Type species: Machaerites stygicus Park, 1951: 46 by original designation.

Subterrochus Park 1960: 91 (as subgenus of Machaerites ). Type species: Machaerites ferus Park, 1960: 91 by original designation. New synonymy

Included species:

Speleochus blanchardensis Carlton. New species. Type locality: Blanchard Springs Caverns, Stone

Co., Arkansas. Types deposited in FMNH (holotype) and LSAM (paratypes) .

Speleochus croceus Park, 1960: 78 . Type locality: Lott Cave, near Brownsboro , Madison Co., Alabama. Types deposited in FMNH (one male paratype examined).

Speleochus eurous ( Park, 1960: 79) . New combination ( Subterrochus ). Type locality: Jess Elliot Cave , Jackson Co., Alabama. Type deposited in the University of Alabama Natural History Museum , Tuscaloosa , Alabama ( UANH) (not examined, decision based on original description) .

Speleochus ferus Park, 1951: 49 . Transferred to Subterrochus: Park (1960: 91) . Combination reinstated. Type locality: Aladdin Cave, Sharps Cove, Madison Co., Alabama. Types deposited in UANH (holotype) and FMNH (paratypes) (one male and one female paratype examined).

Speleochus macosar Carlton. New species. Type locality: Whippoorwill Cave , Madison Co., Arkansas. Types deposited in FMNH (holotype) and LSAM (paratypes).

Speleochus steevesi ( Park, 1960: 80) . New combination ( Subterrochus ). Type locality: Guffey Cave Cave , Marshall Co., Alabama. Types deposited in FMNH (two male paratypes examined) .

Speleochus stygicus Park, 1951: 47 . Type locality: Monte Sano, Madison Co., Alabama. Types deposited in UANH (holotype) and FMNH (paratypes) (two male paratypes examined).

Speleochus synstygicus Park, 1956: 64 . Type locality: Barclay Cave, Madison Co., Alabama. Types deposited in FMNH (one male paratype examined).

Speleochus macosar Carlton , new species ( Figs. 1, 2 , 5, 7–8, 9a, 10–13 , 16 )

Type Material. Holotype (male). USA: AR: Madison Co., Whippoorwill Cave , 24 Aug. 2008, M. Slay ( FMNH) . Paratypes (n = 5). Same locality as holotype , 11 Jul. 2009, 1 ♂, 2 ♀♀, M. Slay, C. Brickey; 29 Aug. 2009, M. Slay , C. M. Slay, 1 ♂ ; 23 Dec. 2009, M. Slay , 1 ♂ (all LSAM) .

Etymology. The specific epithet is a phonetic combination of letters honoring the Madison County Search and Rescue Team (i.e., MA dison CO ounty S earch A nd R escue), who conduct training exercises in Whippoorwill Cave, where all specimens were collected.

Description of Male. Measurements: Head 0.38 mm long (clypeal margin to posterior of occiput), 0.32 mm wide; pronotum 0.38 mm long, 0.33 mm wide; elytra 0.54 mm long, 0.69 mm wide (maximum width slightly anterior to posterior

margin); median lengths of apparent abdominal tergites 1–6, respectively, 0.10, 0.15, 0.12, 0.12, 0.12, 0.09 mm. Antennomeres 1–11, respectively, 0.19, 0.07, 0.05, 0.03, 0.02, 0.02, 0.02, 0.02, 0.03, 0.05, 0.17 mm. Maxillary palpomeres 1–4, respectively, 0.04, 0.28, 0.10, 0.29 mm. Aedeagus 0.29 mm long, 0.16 mm wide. Maximum length (combined lengths of head, pronotum, elytra, and tergites 2–6) 1.90 mm. Color: Body and appendages light brown, evenly covered by short, sparse, semierect pubescence, length of individual setae about equal to dis- tance between them. Head: Tempora moderate, evenly rounded to cervical constriction. Vertexal foveae small, nude, located posterior to shallow, weakly trapezoidal frontal depression, the lateral margins of which are convergent to interantennal frontal boundary. Frons declivous to labrum at approximately 45° angle. Antennae short and unmodified except for elongate antennomere 1. Labrum expanded distally, apical margin straight, lateral angles rounded. Mandibles sickle-shaped with 3 incisor teeth. Maxillae and labium typical for subfamily, including minute, 2-segmented labial palpi. Maxillary palpi elongate, slightly exceeding length of antennae when extended, palpomere 1 recurved and obliquely joined to palpomere 2, palpomere 2 narrow in basal four-fifths, then strongly procurved and capitate distally, covered with prominent, rounded tubercles, palpomere 3 straight, with a smaller number of tubercles on lateral face, palpomere 4 securiform, narrow at base, curved anteriorly, then laterally and expanded to the shape of an elongate shoe, lacking tubercles but covered with dense, erect pubescence. Eyes completely absent, ocular area prominent laterally, then abruptly constricted ventrally to projecting anterior gular area. Mandibular ocular carinae nearly obliterated, scarcely indicated just ventral to antennal insertions. Venter of head strongly projecting anterior to gular foveae, bearing paired patches of fine tubercles, each of which bears a fine, elongate seta projecting from its middle. Thorax: Prothorax strongly convex, rounded, unmodified, lacking mediobasal fovea and subbasal sulcus, bearing small basolateral foveae. Prosternum bearing closely approximate lateral procoxal foveae, other foveae absent. Median mesosternal foveae present, divergent dorsally above lateral mesosternal foveae. Lateral mesosternal foveae present, prominent and paired, with anterior and posterior branches. Lateral metasternal foveae absent. Lateral mesocoxal foveae present. Metaventrite afoveate. Elytra narrow basally, then strongly wider posteriorly, simple, without traces of foveae or striae. Mesotrochanters broadly produced and carinate ventrally. Abdomen: Abdominal segments simple, unmodified, and lacking all traces of foveae. Genitalia: Aedeagus symmetrical, parameres evenly, narrowly convergent, each bearing two elongate setae laterally, internal sac bearing pair of elongate, symmetrical accessory sclerites.

Description of Female. Similar to male except gular region of head less produced ventrally, lacking paired patches of fine tubercles and specialized elongate setae, and with mesotrochanter normally convex in outline.

Comments. The gular region of males of S. macosar is mildly modified and lacks a transverse shelf. Males of several species have unmodified gulae possessing, at most, paired subapical tufts of specialized setae. Others possess more profoundly modified gulae that include transverse gular shelves, such as that of S. blanchardensis . The gulae of S. macosar males lack a transverse shelf, but do possess paired patches of small tubercles with a large seta emerging from the middle of the patch. The expanded sigmoid fourth maxillary palpomere is unique among North American species. In S. blanchardensis , the fourth palpomere presents a weak version of this shape, but in other species it is elongate cylindrical or weakly securiform, curved, and expanded. The aedeagus of S. macosar is similar to that illustrated for S. ferus by Park (1960: 103) and is similar to that of several other species, suggesting that aedeagal morphology is less useful for diagnosing species within this genus than it is in most other genera of pselaphines.

Whippoorwill Cave is a limestone cave on Arkansas Game and Fish Commission Wildlife Management Area property. It is approximately 2 km in length and has several levels that connect the various rooms. Most areas of the cave are high enough for a person to stand upright ( Krist and Prigmore 2004). This and other caves in Madison County are popular with recreational spelunkers. Access to Whippoorwill Cave is currently restricted because of white nose syndrome in the native bat population.

The following collecting notes were provided by Michael Slay (MES) of The Nature Conservancy:

“The first specimen was collected by MES while participating in a practice cave rescue segment of a basic cave rescue training course offered by the Madison County Search and Rescue team. The beetle was collected from the underside of a small piece of damp wood lying on the clay floor near the wall of a cave passage approximately 200 m from the entrance. Following the initial collection, MES visited the cave several times over the next year in attempt to acquire more specimens. During these trips, numerous in-cave habitats and passages (Whippoorwill Cave has approximately 1,950 m of mapped passages) were searched for beetles using teams of 2–3 people. Search effort at each location ranged from 15–30 minutes. Total time spent searching per trip ranged from 5–6 hours. On 11 July 2009, four specimens were collected. Three of the beetles were collected in the same passage as the initial beetle. These beetles were individually found under small stones that were lightly attached to the clay floor. Some organics, small pieces of woody debris and bat guano, were also scattered among the rocks. The fourth specimen was collected deeper in the cave, 250 m from the entrance, under a large flat rock resting on a clay floor. On 29 August 2009, a single individual was collected 98 m from the entrance under a rock on a breakdown covered floor. On 23 December 2009, another beetle was collected in the same location as the initial specimen from under a rock that was slightly embedded into the clay floor and proximal to an old bat carcass covered in fungi. Other cave-limited taxa observed in association with these beetles were Apochthonius ( Pseudoscorpiones : Chthoniidae ) and Pygmarrhopalites ( Collembola: Arrhopalitidae ).”

Speleochus blanchardensis Carlton , new species ( Figs. 3, 4 , 6, 9b , 14 , 17 )

Type Material. Holotype (male). USA: AR: Stone Co., Blanchard Springs Caverns, 35.9636°, −92.1791°, under rock in the maze section of wild cave tour, M. Slay, C. M Slay, 7 Nov. 2009 ( FMNH) . Paratypes (n = 3). Same locality as holotype, area around station 13, 1 Apr. 2010, M. Slay, D. Carpenter, 1 ♀; near station 13, 17 Mar. 2010; M. Slay, K. Furr, 2 ♂♂ (all LSAM) .

Etymology. The specific epithet refers to Blanchard Springs Caverns in Stone County, Arkansas, where all specimens of this species were collected.

Description of Male. Measurements: Head 0.40 mm long (clypeal margin to posterior of occiput), 0.31 mm wide; pronotum 0.38 mm long, 0.36 mm wide; elytra 0.52 mm long, 0.64 mm wide (maximum width slightly anterior to posterior margin); median lengths of apparent abdominal tergites 1–6, respectively 0.11, 0.14, 0.14, 0.10, 0.14, 0.11 mm. Antennomeres 1–11, respectively, 0.24, 0.07, 0.05, 0.04, 0.02, 0.02, 0.02, 0.02, 0.05, 0.06, 0.19 mm. Maxillary palpomeres 1–4, respectively, 0.03, 0.27, 0.06, 0.32 mm. Aedeagus 0.26 mm long, 0.13 mm wide. Maximum length (combined lengths of head, pronotum, elytra, and tergites 2–6) 1.93 mm. Color: Body and appendages medium brown, evenly covered by long, sparse, semierect pubescence, length of individual setae about twice the distance between them. Head: Tempora moderate, evenly rounded to cervical constriction. Vertexal foveae small, nude, located posterior to shallow, weakly trapezoidal frontal depression, the lateral margins of which are convergent to interantennal frontal boundary. Frons declivous to labrum at approximately 45° angle. Antennae short and unmodified except for elongate antennomere 1. Labrum expanded distally, apical margin straight, lateral angles rounded. Mandibles sickle-shaped with 3 incisor teeth. Maxillae and labium typical for subfamily, including minute, 2-segmented labial palpi. Maxillary palpi elongate, slightly exceeding length of antennae when extended, palpomere 1 recurved and obliquely joined to palpomere 2, palpomere 2 narrow in basal fourfifths, then weakly procurved and clavate distally, covered with prominent, rounded tubercles, palpomere 3 straight, with a smaller number of tubercles on lateral face, palpomere 4 elongate securiform, narrow at base, then weakly curved anteriorly, expanded along mesial margin in basal one-third, weakly, evenly concave along lateral margin, lacking tubercles but covered with dense, erect pubescence. Ocular area prominent laterally, then abruptly constricted ventrally to projecting anterior gular area. Mandibular ocular carinae strong, extending from clypeus to tempora. Venter of head strongly projecting anterior to gular foveae, bearing a prominent, anterior, ventrally projecting shelf, the anterior margin of which is emarginate and bears a median pair of elongate hyaline processes. Lateral corners of shelf angulate, each bearing a clump of elongate setae. Gular region posterior to base of shelf bearing 3 pairs of elongate setae in a close set series. Excavation formed by shelf bearing paired clusters of 3 elongate setae each near anterior margin. Area of head dorsal to projecting shelf sharply carinate laterally. Thorax: Prothorax strongly convex, rounded, unmodified, lacking mediobasal fovea and subbasal sulcus, bearing small, basolateral foveae. Prosternum bearing closely approximate lateral procoxal foveae, other foveae absent. Median mesosternal foveae present, divergent dorsally above lateral mesosternal foveae. Lateral mesosternal foveae present, prominent, unpaired, with posterior branches only. Lateral metasternal foveae absent. Lateral mesocoxal foveae present. Metaventrite afoveate. Elytra narrow basally, then strongly widened posteriorly, simple, without traces of foveae or striae. Mesotrochanters weakly convex ventrally with short carinate area near midpoint. Abdomen: Abdominal segments simple, unmodified, and lacking all traces of foveae. Genitalia: Aedeagus slightly asymmetrical, right paramere larger and broader than left, each bearing series of setae laterally, internal sac bearing pair of elongate, accessory sclerites, right larger and more elongate. Internal sac bearing field of small spinules surrounding bases of accessory sclerites.

Description of Female. Similar to male except gular region of head simply tumid and lacking sexual modifications, and mesotrochanter evenly convex in outline, not produced at midpoint.

Comments. A gular excavation covered by an anterior projecting shelf occurs in males of two other North American species of Speleochus . The structure in S. blanchardensis is most similar to that of S. ferus among species examined or illustrated. Both possess a transverse, anterior, projecting shelf on the gular surface of the head that bears a pair of thick median processes. The shelf is slightly more pronounced in S. blanchardensis than in S. ferus , and the median processes are broader and slightly widened at the base (slender and parallel in S. ferus ). The gular shelf of S. steevesi is more limited than in either S. blanchardensis or S. ferus , and the median processes are short and rounded. In S. macosar , which also occurs in north Arkansas caves, the gular shelf is entirely absent. The terminal segment of the maxillary palpus of S. blanchardensis is strongly convex basally along its posterior aspect, and weakly concave along the anterior aspect. It is not strongly curved anteriorly at the base as it is in S. macosar . The parameres of S. blanchardensis are more narrow and acute than those of S. macosar and more elongate and less symmetrical than those of S. ferus .

The type locality, Blanchard Springs Caverns, is a large, multilayer cave system managed by the U.S. Forest Service (Sylamore Ranger District, Ozark National Forest). Portions of the cave have been included in guided tours for the public since 1973, when artificial access was completed. Access was extremely difficult prior to this. The vertical section occupied by the cave system spans numerous limestone and dolomite formations ranging from late Ordovician to early Carboniferous ( Anonymous 2011).

The following collecting notes were provided by Michael Slay of the The Nature Conservancy:

“The first specimen was collected by Christy Slay during a preliminary trip to establish monitoring stations for a multi-season study of the invertebrate community found in the cave. On 7 November 2009, a single individual was collected from under a lightly embedded rock in “The Maze” section of cave along the Wild Cave Tour route. During the subsequent invertebrate community study, considerable effort was made to collect additional beetle specimens in “The Maze”, at each of 24–27 invertebrate monitoring stations distributed along 3 commercial tour routes (Wild Cave Tour, Discovery Trail, and Dripstone Trail), and at random locations between monitoring stations. Beetle searches occurred over a period of 16 trips from winter 2009 to summer 2010. Trips consisted of 2–3 people, and total time in cave was 5–6 hours per trip. The species was only observed in “The Maze” section of the cave, and individuals were found separately under rocks slightly embedded into the clay floor. Soil temperature, air temperature, and relative humidity were recorded at the location where beetles were collected during 6 monitoring trips. Soil temperature ranged from 14.0–14.3°C, air temperature ranged from 14.2–14.6°C, and relative humidity ranged from 92.0–97.6%. Other cave-limited taxa observed in association with these beetles were Causeyella causeyae ( Diplopoda: Trichopetalidae ), Pseudosinella ( Collembola: Entomobryidae ), and Litocampa ( Diplura : Campodeidae ).”

Figures

Figs. 1–4. Speleochus spp. 1) S. macosar, dorsal view; 2) S. macosar, lateral view; 3) S. blanchardensis, dorsal view; 4) S. blanchardensis, lateral view.

Figs. 5–10. Speleochus spp. 5) S. macosar, head, ventral view; 6) S. blanchardensis, head, dorsal view; 7) S. macosar, antenna, dorsal view; 8) S. macosar, prothoracic leg, anterior view; 9a) S. macosar, mesothoracic leg, anterior view; 9b) S. blanchardensis, mesothoracic coxa and trochanter, anterior view; 10) S. macosar, metathoracic leg, anterior view. Scale bar equals 0.2 mm for all figures.

Figs. 11–15. Thoracic ventrites, ventral view. 11) Speleochus macosar, prothorax; 12) S. macosar, meso-metathorax; 13) S. macosar, meso-metathoracic foveae; 14) S. blanchardensis, meso-metathoracic foveae; 15) Tychobythinus carolinae (Casey) (Montgomery Co., Arkansas), meso-metathoracic foveae. Scale bars equal 0.1 mm. Foveal terminology follows Chandler (2001): LMCF = lateral mesocoxal fovea; LMSF = lateral mesosternal fovea; LMTF = lateral metasternal fovea; LPCF = lateral procoxal fovea; MMSF = median mesosternal fovea.

Figs. 16–17. Aedeagi, dorsal view. 16) Speleochus macosar; 17) S. blanchardensis. Scale bars equal 0.1 mm.