Euscorpius trejaensis, Tropea & Parmakelis, 2022

Tropea, Gioele & Parmakelis, Aristeidis, 2022, Reconsideration of some populations of Euscorpius concinnus complex (Scorpiones, Euscorpiidae), ZooKeys 1100, pp. 117-164 : 117

Euscorpius trejaensis sp. nov.

Figs 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27

Type material.

Holotype: ♂, Italy, Latium, near Calcata (VT), Treja’s valley, 42.21953°N, 12.4175°E, 21 June 2020, leg. G. Tropea, (GTC 1184).

Paratypes: Italy: Latium: near Calcata (VT), Treja’s valley, 42.21953°N, 12.4175°E, 21 June 2020, leg. G. Tropea, 4 ♀♀ (GTC); near Calcata (VT), Treja’s valley, 42.2080833°N, 12.4141667°E, 13 June 2009, leg. G. Tropea, S. Tropea, 3 ♀♀ (GTC); near Calcata (VT), Treja’s valley, 28 July 2009, leg. G. Tropea, 2 ♂♂, 2 ♀♀ (GTC); same data but 2 April 2012, leg. G. Tropea, 3 ♀♀ (GTC); same data but 42.21413°N, 12.41629°E, 114 m, 6 May 2014, leg. G. Tropea, 3 ♂♂, 9 ♀♀ (GTC 498-508, 851); same data but 42.21930°N, 12.418°E - 42.2188889°N, 12.4154°E, between the 100 e i 150 m, 8 April 2018, leg. G. Tropea, 7 ♀♀ (GTC 1092-1098); Rio Fiume, Monti della Tolfa, 112 m, 42.07565°N, 11.96410°E, 11 May 2014, leg. G. Tropea, 5 ♂♂, 12 ♀♀ (GTC 509-525); Rio Fiume, Monti della Tolfa, 9 April 2012, leg. G. Tropea, 1 ♂, 3 ♀♀ (GTC 128-131).

Other examined specimens

(not included in type series). Italy: Latium: near Calcata (VT), Treja Valley, 42.21953°N, 12.4175°E, 21 June 2020, leg. G. Tropea, 2 ♀♀, of which one subadult (GTC); Lago di Bracciano, Oriolo Romano (VT), 491 m, 6 March 2013, 3 ♂♂ (CNBFVR); VT, Lago di Vico, loc. Monte Venere, 701 m, 6 March 2013, 7 ♂♂, 7 ♀♀ (CNBFVR); Monti Cimini, Monte Venere verso E Cerreta 560-580 m, 24 July-23 August 1985, leg. S. Pedullà, M. Rellori, 6 ♂♂ (MZUR 92-95, 98, 99); near Calcata (VT), Treja’s valley, 28 July 2009, G. Tropea, 6 ♂♂, 2 ♀♀ (NCS); same data but 2 April 2012, G. Tropea, 1 ♂ (NCS); Oriolo Romano, 1 May 2010, G. Tropea, 1 ♂, 2 ♀♀ (NCS); Canale Monterano (TV), 22 May 2010, G. Tropea, 4 ♀♀ (NCS); Rio Fiume, Monti della Tolfa, 9 April 2012, G. Tropea, 6 ♂♂, 7 ♀♀ (NCS); same data but 22 May 2010, 4 ♀♀ (NCS); Gorge of the Biedano, Barbarano Romano (TV), 27 March 2010, G. Tropea, 1 ♂, 1 ♀ (NCS); Castel Giuliano (RM), 42.03381°N, 12.13032°E, 10 April 2010, G. Tropea, 1 ♂, 1 ♀ (NCS).

Etymology.

The specific epithet is derived from Treja, the river that flows in the homonymous valley where the first specimens of E. trejaensis sp. nov. were collected.

Geographic range.

Italy: Latium (right side of the Tiber River; Fig. 32 ).

Diagnosis.

A small Euscorpius species, total length 24-28 mm. Colour of adults mostly dark brown with darker marbling on most of the body, including chelicerae. The number of trichobothria on the pedipalp manus ventral surface is four (V1-3 + Et1). Trichobothria est and dsb on fixed finger are respectively located distally and proximally to the notch of the fixed finger. The number of trichobothria on the pedipalp patella ventral surface is usually seven and eight (seven in 34.07% of the pedipalps examined). The number of trichobothria on pedipalp patella external surface is usually: eb = 4, eba = 4, esb = 2, em = 4, est = 4, et = 6. Trichobothrium i of the femur is slightly proximal to or at the same level of d. The pectinal teeth number in males usually is eight (seven to nine) and in females usually is seven (six to eight). Dorsal patellar spur well developed. Femur is slightly shorter than the patella. Carapace approximately as long as wide, but it tends to be shorter than long in the females. Carinae V1 follows an external direction to the trichobothria Et1, without forming a Y-shape. Spinules on legs ending with a Y-shape. Ventrolateral and ventromedian carina on metasomal segment V well formed by small, spaced, slightly serrulated granules.

Trichobothrial and pectinal teeth count variation.

The variation observed in 113 examined specimens (43 ♂♂ and 70 ♀♀) is given below (left/right asymmetry not specified).

Pectinal teeth in males (n = 86): 7/8 (7); 8/8 (28), 8/9 (5), 8/10 (1), 9/9 (2); in total, 7 in 8.14% (7), 8 in 80.23% (69), 9 in 10.46% (9) and 10 in 1.16% (1); mean = 8.05, SD = 0.48.

Pectinal teeth in females (n = 137): 6/6 (9), 6/7 (11), 7/7 (41), 7/8 (5), 8/? (1), 8/8 (1), 9/8 (1); in total, 6 in 21.17% (29), 7 in 71.53% (98), 8 in 6.57% (9), 9 in 0.73% (1); mean = 6.87, SD = 0.54.

Pedipalp patella trichobothria Pv (n = 226): 6/6 (1), 6/7 (4), 7/7 (22), 7/8 (29), 8/8 (52), 9/8 (3); in total, 6 in 2.65% (6), 7 in 34.07% (77), 8 in 61.95% (140), and 9 in 1.33% (3); mean = 7.62, SD = 0.56.

Pedipalp patella trichobothria Pe (n = 159): et = 5/4 (2), 5/5 (3), 4/6 (1), 5/6 (9), 6/? (1), 6/6 (60), 7/6 (1), 7/7 (3); in total, 4 in 1.89% (3), 5 in 10.69% (17), 6 in 83.02% (132) and 7 in 4.40% (7); mean = 5.90, SD = 0.47;

est = 3/3 (1), 4/? (1), 4/3 (2), 4/4 (79), 5/4 (1); em = 3/? (1), 3/3 (1), 3/4 (10), 4/4 (71), 5/4 (1); esb = 2/? (1), 1/2 (2), 2/2 (81); eba = 3/3 (1), 3/4 (6), 4/? (1), 4/4 (74), 4/5 (2); eb = 3/4 (1), 4/? (1), 4/4 (82).

Description of the male holotype.

Colouration. A general dark brown base colour with more or less marked paler marbling or reticulation, reddish brown, in the less granulated areas, especially of the metasoma, legs, pedipalps and chelicerae; telson mostly dark brown with two ventrally longitudinal pale brown stripes and one for each side, with reddish brown distal part of the sting; ivory chelicerae with dark brown reticulation; chelae with fingers ranging from pale yellowish brown to dark reddish brown with dark blackish brown reticulation; legs with almost completely ivory tarsus, the basitarsus and tibia are mostly ivory, but with dark blackish brown marbling externally, almost ivory internally, the patella and femur are mostly dark with paler marbling externally, and mostly ivory internally; pectines and genital operculum whitish ivory; sternites range from almost completely black with pale spot on the most distal to very pale brownish at the most proximal.

Carapace. Almost completely covered by a dense fine granulation; anterior edge is granulate; deep posterior lateral furrows; two pairs of lateral eyes, and a pair of median eyes; length from centre of median eyes to anterior margin is 40.98% of carapace length.

Mesosoma. The tergites are densely covered with a fine granulation; sternites glossy and finely punctuated; small spiracles inclined to ~ 40° downward towards outside.

Metasoma. Dorsal carinae on segments I-IV with spaced granules; ventrolateral carinae on segment I absent, on segment II and III smooth or obsolete, on segments IV, little marked with some small and spaced granule, with small slightly serrulated granules on segment V; ventromedian carinae absent on segment I-IV, on segment V it consists of small, slightly serrulated granules; dorsal and lateral intercarinal surfaces on segments I-IV are mostly finely granulated, especially on dark marbling, while the ventral surfaces are mostly smooth, the V segment is mostly finely granulated.

Telson. Vesicle with a few small granules, with ventral setae of different size, especially near the vesicle/aculeus juncture.

Pectines. Teeth number 8/8; middle lamellae number 5/5; several microsetae on proximal area of teeth, marginal lamellae, and middle lamellae.

Genital operculum. The genital operculum is formed by two longitudinally devised subtriangular sclerites with genital papillae protruding.

Sternum. Pentagonal shape, type 2; slightly wider than long, with a deep posterior emargination.

Pedipalps. Coxa and trochanter with tuberculated carinae. Femur: dorsal internal and external and ventral internal carinae tuberculated; irregular ventral external carinae formed by tubercles only on 1/3 or 1/2 of femur length; external median carinae formed by lightly serrulated tubercles; anterior median carinae formed by some spaced conical tubercles with three macrosetae; intercarinal spaces granulated. Patella: dorsal and ventral internal carinae tuberculated; ventral external carinae crenulated; dorsal external carinae slightly crenulated; intercarinal surfaces finely granulated, especially on the dark reticulations near the carinae. Dorsal patellar spur well developed. Chela: chelal carina D1 is distinct, strong, dark, and from smooth to slightly crenulated with a few tubercles proximally; D4 is dark with flat joined tubercles; V1 is distinct, strong, dark, from rough to crenulated, following an external direction to the trichobothria Et1; V3 is rounded with scattered granules; external carina granulated; intercarinal tegument granulated; the fixed and movable fingers with small, marked notch and lobe, respectively.

Finger dentition. In the distalmost part a DD is present on the tip; MD is formed by very small denticles closely spaced, forming an approximately straight line, discontinued at level of the OD; fixed finger has 6/6 OD and 10/10 ID; movable finger has 8/8 OD and 13/11 ID.

Trichobothria. Chela: trichobothria on the pedipalp manus ventral surface V = 3/3 (V1-3) + Et1 = 1/1; trichobothrium V4 situated on the external surface of the chela carina near the carina V1; trichobothrium ratio of et-est/est-dsb is ~ 1.43 and 1.25. Patella: Pv = 7/7; et = 5/6, est = 4/4, em = 4/4, esb = 2/2, eba = 4/4, eb = 4/4. Femur: trichobothrium d is slightly proximal to i, while trichobothrium e is well distal to both d and i, and situated on dorsal surface on dorsal external carina.

Legs. Two pedal spurs present; no tarsal spur; ventral row of tarsus with a total of 10/13 spinules on leg III, of increasing size from proximal to distal, ending with two spinules to form a Y-shape; three main flanking tarsal setae present. Tubercles present on ventral and dorsal surface of all leg femora.

Chelicerae. Typical of the genus Euscorpius .

Description of the hemispermatophore.

Type A. It has a well-developed lamina tapered distally; well-developed basal constriction present; truncal flexure present; median projection with lde, ldi, and lb; internal projection distally with 5-7 tines in its crown. The number and the shape of tines of the crown varied between specimens and between the right and the left hemispermatophores.

Comments.

Euscorpius trejaensis sp. nov. is geographically the closest species to E. latinus sp. nov., also part of the E. concinnus group, which seem to be divided from each other by the Tiber River. As mentioned above, this geographical proximity does not seem to result in a particular genetic relatedness. Indeed, according to the concatenated phylogenetic tree 16S + COI, E. trejaensis sp. nov. is paired with E. stefaniae sp. nov., with E. niciensis stat. nov. basal to them and between E. latinus sp. nov. and them. Regarding the divergence in 16S, between E. trejaensis sp. nov. and E. latinus sp. nov., it ranges from 2.7% to 3.1%, 3.1% with E. stefaniae sp. nov., and 2.7% with E. concinnus and E. niciensis stat. nov. Morphologically, like the other species of the E. concinnus group and the many cryptic species complex that have been described in recent years, E. trejaensis sp. nov. is difficult to distinguish without knowing its origin and having a good sampling size. As for the trichobothrial Pv values, we see that E. trejaensis , together with E. latinus , has the lowest average of Pv, ~ 7.60, having the percentage of Pv = 7 a little lower than in E. latinus sp. nov. (34.07% against 39.68%), but much higher than the other species treated here (2.78-13.33%); it has a percentage of Pv = 8 similar to E. concinnus and E. latinus sp. nov. (60.32-65.25%), much higher than E. niciensis stat. nov. (25% vs. 61.95%) and lower than E. stefaniae sp. nov. (81.67%). As for the Dp in males, E. trejaensis sp. nov. has the lowest average, the highest percentage of Dp = 8 and the lowest percentage of Dp = 9. These values are very different from those of E. niciensis stat. nov. and E. stefaniae sp. nov., and more similar to those of E. concinnus and E. trejaensis sp. nov. The Dp in females also reflects the same trend, albeit to a lesser extent. In fact, E. trejaensis sp. nov. has the lowest average and the highest percentage of Dp = 7 and 6, and the lowest percentage of Dp = 8.

The distribution of Euscorpius trejaensis sp. nov. affects the central-north western part of Lazio, on the right side of the Tiber River. However, it must be ascertained whether its diffusion continues northward into Tuscany and Umbria. Euscorpius. trejaensis sp. nov. was found from 100 m a.s.l. on the Tolfa Mountains to 700 m a.s.l. on Mount Venere. This lower altitude is probably caused by the fact that this area of Lazio has no particularly high mountain formations, but mostly hills and low mountains. Euscorpius trejaensis sp. nov. has always been found in natural areas, mostly in mesophilic forests, often with nearby streams, or in any case in very humid microhabitats. It showed mostly corticolous but also lapidicolous tendencies, having been found especially under the bark or cracks of fallen and rotting branches and trunks, or very damp, but also under stones, especially where there were few or no adequate branches. Euscorpius trejaensis sp. nov. was found a few centimetres from E. italicus once in the type locality; however, despite having examined the areas several times over the years, E. italicus has no longer been found. Probably the latter prefer rural and less humid areas, unlike E. trejaensis sp. nov., so their meeting is infrequent.

Euscorpius trejaensis sp. nov., like most species of Euscorpius , mate in spring and summer. The male grabs the female’s chelae and is in a constant state of alert and distrust (Fig. 24 ); the male stings the female between claw and patella of the pedipalp (Figs 25 , 26 ), after which the female become calmer and cooperative. Thus begins a push and pull similar to a dance, but without the typical kiss of the scorpion (i.e., holding with chelicerae) observed in other species of scorpions (such as those belonging to the genus Heterometrus Ehrenberg, 1828), until the male finds a suitable surface to place the spermatophore and pulls the female until she goes over it, and the spermatophore fits into the genital operculum of female. Births usually take place in the summer of the following year, mostly in the months of July and August.

Figures

Figure 17. Dorsal and ventral view of Euscorpius trejaensis sp. nov. male holotype. Scale bar: 4.00 mm.

Figure 18. Dorsal and ventral view of Euscorpius trejaensis sp. nov. female paratype. Scale bar: 4.00 mm.

Figure 19. Euscorpius trejaensis sp. nov. male holotype except Figs C and N, that are of a female paratype A carapace B external view of chela of adult male C external view of chela of adult female D ventral view of pedipalp patella E dorsal view of pedipalp patella F external view of pedipalp patella G ventral view of chela H dorsal view of chela I ventral view of metasomal segment V J lateral view of metasomal segment V K telson of adult male L telson of adult female.

Figure 20. Euscorpius trejaensis sp. nov. male photographed in nature feeding on an insect inside a small cavity of a tuff stone.

Figure 21. Pregnant Euscorpius trejaensis sp. nov. found under the bark of a trunk.

Figure 22. Barked trunk in which some specimens of Euscorpius trejaensis sp. nov. were found.

Figure 23. Specimen of Euscorpius trejaensis sp. nov. which has recently carried out ecdysis under a bark.

Figure 24. Beginning of mating of Euscorpius trejaensis sp. nov., with the male grabbing the female's chelae.

Figure 25. Lateral view of a male calming the female by stinging during mating.

Figure 26. Dorsal view of a male calming the female by stinging during mating.

Figure 27. Example of the habitat of Euscorpius trejaensis sp. nov.

Figure 32. Maps of the known geographic ranges of the species treated herein.