Serradigitus miscionei Ayrey, 2011

Ayrey, Richard F., 2011, Serradigitus miscionei (Scorpiones: Vaejovidae), a new species from southern Arizona, Euscorpius 111, pp. 1-13 : 2-9

Serradigitus miscionei Ayrey , sp. nov.

( Figs. 1 , 3–16 )

Diagnosis. Small reddish-brown scorpions ( Fig. 1 ). The total length is 25 mm. The female pectinal tooth count is 13–14 (13.09) [44] and the number of modified pectinal teeth (diminished or completely lacking sensorial area) is 1.45 (20). The basal tooth, lacking a sensorial area, is subovoid and same length as the adjacent tooth. The trichobothrial pattern is orthobothriotaxic type C ( Fig. 4 ). Trichobothria ib and it are positioned on the basal third of the fixed finger, ib located at the level of ID denticle 6, it located half way between ID denticles 5 and 6 ( Figs. 4 , 10 ). Inner accessory denticles (IAD) are lacking on the chelal fingers. The movable and fixed chelal fingers have 7 and 6 inner denticles (ID), respectively. The pedipalp chela fixed finger has 4 subrows of median (MD) denticles, 3 OD denticles and 6 ID denticles. Movable finger has 4 subrows of median (MD) denticles, 3 OD denticles and 7 ID denticles. The movable finger and fixed finger OD denticles are serrated and indistinguishable after OD -3, and the distal denticles are elongated and hook-like with a distal “whitish patch”. Ventromedian (VM) carinae of metasomal segments I–IV are crenulate. Metasomal segments IV and V are the same color as I through III, with metasomal segment III about as long as wide and the ratio of metasomal segment V length/width is 1.69– 1.72. A small subaculear tubercule is present on the telson.

Type material. USA: Arizona: Holotype female, Walnut Gulch, Cochise County (35°14’14.2”N, 112°06’44.4”W), 08 March 2009 ( R. F. Ayrey) ( CAS = California Academy of Sciences ) . Paratype female #2, Walnut Gulch , Cochise County (35°14’14.2”N, 112° 06’44.4”W), 08 March 2009 ( R. F. Ayrey) ( CAS) . Paratype female #5, Walnut Gulch , Cochise County (35°14’142”N, 112°06’44.4”W), 25 April 2009 ( R. F. Ayrey) ( CAS) . Paratype female, Cienega Creek , Pima County, 25 April 2009 ( R. F. Ayrey) ( CAS) .

Etymology. This species was named in honor of Tom Miscione for originally discovering the scorpions.

Distribution. Known from the type locality Walnut Gulch, Cochise County, Arizona and the San Pedro and Santa Cruz River drainages of Southern Arizona, USA. See map in Figure 17 .

Measurements (in mm). Male unknown. Holotype (female): total length 24.71; carapace length 3.06; carapace width at median eyes 2.89; mesosoma length 9.19; metasoma length 12.46; metasomal segment 1 length/width 1.26/1.96; segment II length/width 1.44/ 1.81; segment III length/width 1.74/1.79; segment IV length/width 2.32/1.76, segment V length/width 2.88/ 1.70; telson: length 2.82; telson vesicle length/ width/depth 1.67/1.11/0.80; aculeus length 1.15. Pedipalps: total length 10.13; femur length/width 2.49/0.86; patella length/width 2.93/0.98; chela length 4.71; chela palm length/width/depth 1.81/1.01/0.92; movable finger length 2.99; fixed finger length 2.48.

Paratype (female): total length 25.15; carapace length 3.17; carapace width at median eyes 2.59; mesosoma length 9.58; metasoma length 12.40; Metasoma: segment 1 length/width 1.22/1.92; segment II length/width 1.53/1.85; segment III length/width 1.71/1.74; segment IV length/width 2.23/1.71; segment V length/width 2.92/1.69. Telson: length 2.79; Telson Vesicle length/ width/depth 1.63/1.09/0.78; Aculeus length 1.16. Pedipalps: total length 10.55; femur/width 2.72/0.95; patella length/width 3.11/1.05; chela length 4.72; chela palm length/width/depth 1.90/1.05/0.96; movable finger length 3.09; fixed finger length 2.57.

Description. Based on holotype female, see Figure 3 for dorsal and ventral views. Table 1 contrasts S. miscionei with other Serradigitus species.

Color. The color is reddish-brown with dusky markings on carapace and tergites, fading to faint on metasoma, pedipalps and legs. Metasomal segments I–V are uniformly reddish-brown. The telson is orangebrown.

Carapace The carapace is finely granular and is longer than the fifth metasomal segment. The anterior margin of the carapace is slightly emarginated. Three lateral eyes on each side. Median furrow moderate and traverses entire length of carapace (see Figs. 5 , 8 ).

Mesosoma. Tergites are finely granular. Tergite VII with two pairs of strong, crenulate carinae. Sternites III– VI smooth. Sternite VII with one pair of weak, granulose carinae. Stigmata are long and slit-like.

Pectines. Pectinal tooth counts for adult females are, 13/13(19), 14/13(2) and 14/14(1) with an average of 13.09(44). One or more of the most proximal pectinal teeth are modified (diminished or completely lacking sensorial area). Mean number of female modified pectinal teeth is 1.45(20) (see Figs. 7 , 12 ). Fulcra 12/12. Middle lamellae 8/8.

Chelicerae. Dorsal edge of movable finger with two subdistal (sd) denticles; ventral edge smooth with well developed serrula comprised of approximately 20 tines on distal half. Ventral edge of fixed finger smooth.

Metasoma. Segments I–III wider than long, IV 1.32 times longer than wide, V 1.73 times longer than wide. Segments I–IV: Dorsolateral carinae moderately strong, crenulate. Lateral supramedian carinae strong, crenulate. Lateral inframedian carinae moderate, crenulate; on posterior four fifths of I, on II present on posterior twothirds, on III present on posterior one fourth, on IV absent. Ventrolateral carinae moderate, crenulate on posterior two thirds of I and posterior three quarters of II–IV. Ventral median carinae moderate, crenulate on posterior three quarters of I and on II–IV. Setal counts on segments I–IV: dorsolaterals, 0:1:1:2; lateral supramedians, 0:1:1:2; ventrolaterals, 2:2:3:3; ventral submedians, 3:3:3:3. Segment V dorsolateral carinae moderate, granulose; lateromedian carinae moderate on anterior four fifths; ventrolateral and ventromedian carinae moderate, crenulate. All intercarinal spaces on metasomal segments I–V moderately granular.

Telson ( Fig. 6 , Figs. 13, 14 paratype female). Ventral surface of vesicle very weakly granular; about 7 to 9 pairs of major setae. Subaculear tubercle very weak (see Figs. 6 , 13 ). Laterobasal Aculear Serrations (LAS) present, holotype exhibiting 6-6 serrations ( Fig. 14 shows these serrations on a paratype).

Pedipalps. Trichobothrial pattern orthobothriotaxic type C ( Vachon, 1974), see Figure 4 . Trichobothrium ib at level of ID denticle 6, trichobothrium it located half midpoint between ID denticles 5 and 6.

Chela ( Fig. 9 ). Palm slightly inflated medially. Dorsal marginal carina moderate; dorsal secondary and external secondary carinae weak; ventroexternal carina weak; digital carina vestigial; ventromedian and ventrointernal carinae vestigial; dorsointernal carina weak, granulose. Fixed finger median (MD) denticles divided into 4 subrows; 3 OD denticles and 6 ID denticles. Movable finger median (MD) denticles divided into 4 subrows; 3 OD denticles and 7 ID denticles. Movable finger and fixed finger OD denticles are serrated and indistinguishable after OD -3. Distal denticles elongated and hook-like with distal ‘whitish patch’. The chela length/width is 1.79.

Femur. Dorsointernal, dorsoexternal, and ventrointernal carinae moderate, crenulate; ventroexternal carina moderate, crenulate. Internal surface with 11 enlarged granules; other surfaces densely, minutely granular.

Patella. Dorsointernal and ventrointernal carinae moderate, crenulate; dorsoexternal and ventroexternal carinae weak, crenulate. Internal surface with up to fourteen enlarged tubercles forming an oblique longitudinal DPS carina; dorsal and ventral surfaces densely, minutely granular; external surface with numerous small granules along midline.

Legs ( Fig. 15 ). Connective tissue between basitarsus and tarsus of right leg III with pedal spurs on both the external as well as internal surfaces. Right leg III tarsus with a single pair of distal spinules.

Variation. Variation was found in the number of modified pectinal teeth with counts of 2/2 (2), 2/1 (3), 1/1 (3) and ½ (2), with a mean of 1.45 (20), 7 of the 10 females examined had at least one pecten with more than one modified pectinal tooth.

Reproduction. All of the 22 specimens examined were found to be adult females. Three females were observed with second instar juveniles on their backs. The number of juveniles were 2 ( Fig. 16 ), 3, and 10; mean = 5 (3). A description of the male will be necessary when specimens become available.

Figures

Figure 1: Serradigitus miscionei, sp. nov., on a vertical sand flake in Walnut Gulch.

Figure 3: Serradigitus miscionei, sp. nov., female holotype, Walnut Gulch, Cochise Co., Arizona, USA. Ventral and dorsal surfaces.

Figure 4: Serradigitus miscionei, sp. nov., female holotype, Walnut Gulch, Cochise Co., Arizona, USA. Trichobothrial pattern.

Figures 5–7: Serradigitus miscionei, sp. nov., female holotype, Walnut Gulch, Cochise Co., Arizona, USA. 5. Carapace and chelcierae, dorsal view. 6. Metasomal segment V and telson, lateral view. 7. Sternopectinal area.

Figures 8–15: Serradigitus miscionei, sp. nov., female paratype, Walnut Gulch, Cochise Co., Arizona, USA. 8. Carapace. 9. Chela, lateral view. 10. Chelal fingers, internoventral view, showing the position of trichobothria ib–it and six and seven inner denticles (ID) of the fixed and movable fingers, respectively. 11. Chelal fingers, external view, showing the highly serrated outer (OD) and median (MD) denticles, diagnostic of the genus. 12. Left pecten showing the lack of peg sensilla on the basal tooth and reduced developed of sensilla on second basal tooth. 13. Metasomal segment V and telson, ventral and lateral views. 14. Closeup of telson aculeus, ventral view, showing the development of the Laterobasal Aculear Serrations (LAS) with seven to eight serrations. 15. Tarsus, left leg III, showing pedal spurs, ventral row of median spinules, and single pair of distal spinules.

Figure 16: Serradigitus miscionei, sp. nov., with second instar juveniles.

Figure 17: Distribution of Serradigitus miscionei, sp. nov., showing the locations of the San Pedro and Santa Cruz Rivers. The (X) is the holotype location and (square) a paratype location.