VENEZUELAN ARACHNIDES: TWO NEW SPECIES OF THE Tityus GENUS (SCORPIONIDA: BUTHIDAE) IN THE STATE OF LARA

Original paper

VENEZUELAN ARACHNIDES. TWO NEW SPECIES OF THE Tityus GENUS (SCORPIONIDA: BUTHIDAE) IN THE STATE OF LARA

M. A. GONZALES-SPONGA

1 Visiting Professor, Laboratory of Cellular Neuropharmacology, Center of Biophysics and Biochemistry, Venezuelan Institute of Scientific Investigations (IVIC)

ABSTRACT. Two new scorpion species of the Buthidae family, Tityus ivic-nancor and Tityus sanarensis, are described in this paper. Both species belong to the "androcottoides" group and live from 1300 to 1400 m. above sea level near the town of Sanare (69º42'17.8"W, 9º45'3.9"N) in the southern part of the state of Lara in Venezuela. The number of Tityus species already known in Venezuela increases to 28 with the inclusion of these two new species. This paper includes a descriptive diagnosis and also a differential diagnosis of the species of Tityus that are geographically related to T. ivic-nancor and T. sanarensis. Drawings of the significant morphological characteristics of male and female specimens and a morphometric table are also included.

KEY WORDS: Scorpions, systematics, Tityus, new species, Venezuela.

INTRODUCTION

The species described in this paper were accidentally found in the Laboratory of Cellular Neuropharmacology of the Instituto Venezolano de Investigaciones Científicas (IVIC). A batch of scorpions used in the study of toxinology of Venezuelan species of Tityus was made. This project was carried out by Dr. Gina D'Suze and Dr. Carlos Sevcik. The description of the new species is of great interest since the scorpions belong to the well-known Tityus genus of the Buthidae family, which are dangerous to human health.

In Venezuela, the Tityus genus comprises 26 known species, to which Tityus ivic-nancor n.sp. and T. sanarensis n.sp. should now be added. The Tityus genus comprises most of the 103 species of scorpions in Venezuela which are distributed in 4 families and 18 genera. Tityus species are spread over all Venezuela except for the central plains with grassy lands and very high temperatures during the dry season and the snowy areas of the high paramo of the Venezuelan Andes.

Some species of Tityus are particularly abundant in densely populated areas of Venezuela such as T. funestus in the Tachira and Southern Merida states and T. discrepans (Karsch, 1879) (8) in the vicinity of the capital city of Caracas. These species are responsible for a high number of human envenomation cases. Given the number of T. ivic-nancor n.sp. specimens (n>300) collected for the above mentioned project, this is also a very abundant species.

The figures were penciled on millimetric paper using a Nikon dissecting microscope with an eyepiece reticle. The figures were all drawn in the same scale. The typical specimens described here are kept in the author's personal collection.

SYSTEMATICS

FAMILY BUTHIDAE Simon, 1879.

GENUSTityus Koch, 1836 (1,3,5,9,10).

GROUP "androcottoides" (10)

Tityus ivic-nancor n. sp.

MATERIAL EXAMINED: 13 male and 90 female adult specimens and 2 females close to adulthood. They were all collected by Dr. Carlos D'Suze (Instituto De Biomedicina, Proyecto de Enfermedades Endémicas de Sanare, state of Lara, Venezuela).

TYPICAL LOCATION: Near the town of Sanare (69º42'17.8"W, 9º45'3.9"N) in the southern part of the state of Lara, Venezuela.

DISTRIBUTION: Below the Yacambú National Park, between the town of Sanare and the hamlets of La Cañada and Versalles, Jiménez District, state of Lara,Venezuela.

HABITAT: Under rocks and in crevices of hilly roadsides; near high tropophilous forests and grassy lands, from 1300 to 1400 m above sea level.

CLIMATE: Gwi of Koeppen.

ETYMOLOGY: ivic = Initials of the Instituto Venezolano de Investigaciones Científicas; nacor = Latin for found, got, stumbled on or upon.

DIAGNOSIS: Tityus ivic-nancor n.sp. is distinguished, is distinguished by the following characteristics: a) marked sexual dimorphism in the chelae; b) pedipalp chelae with almost spherical manus; c) ventral carina is irregular on caudal segments II and IV; d) caudal segments I-V are short, thick and divergent; e) telson is short and broad. It may be differentiated from the species in its group that are geographically close such as T. falconensis González-Sponga (1974) (2), T. barquisimetanus González-Sponga (1994) (6), T. pococki Hirst (1911) (7), T. rugosus Senkel (1932) 10,11) and T. valearae Scorza (1954) (12) by the shape of the manus of the masculine male pedipalp and by mesoventral carinae of caudal segments.

DESCRIPTION 1

CHARACTERISTICS OF MALE SPECIMENS.

Color: ventral side of prosoma, pedipalps (up to the base of the fingers and their distal end), walking legs, caudal segments I and II and sting are light brown; dorsal side of prosoma, mesosoma and caudal segment II are dark brown; caudal segments III and IV and telson vesicle are black.

Carapace: anterior border is slightly obtuse, smooth, without granules and has sinuous lateral borders; posterior border is straight on sides and slightly convex in the middle. Carinae: anterior paramedian carinae are poorly defined and have granules varying in size and separation that are difficult to differentiate from their neighbors; supraocular carinae have small granules spreading over the anterior half and are more clearly defined on the posterior half; posterior paramedian carinae are very irregular and have small elongated granules; anterior marginal carina has granules of different sizes which are irregularly aligned; posterior marginal carina is vestigial on sides and has granules of different sizes in the middle; anterior lateral carinae are poorly defined; they are composed of very small granules, some of them are clustered and others (the lager ones) are aligned. Furrows: anterior median furrow is wide, shallow and covered with many small granules; median ocular furrow is smooth; posterior median furrow deepens progressively towards distal end; it has very small granules in its depth and is flanked by two convexities, by granules of diverse size and by some coriaceous areas; posterior marginal furrows lack ornamentation and derive from distal end of posterior median furrow; posterior lateral furrows are wide and shallow with some small granules in their depth and on their sides.

Median ocular tubercle is prominent; lateral ocular tubercles exhibit a row of granules in their dorsum; the rest of tegument has coriaceous areas and irregularly distributed granules of various sizes; granules are more abundant between the anterior paramedian and anterior lateral carinae, on central lateral area and on the posterior lateral angles of carapace.

Pedipalps: See (Figure 1a). Chela: A chela is shown in (Figure 1b); almost spherical manus with vestigial carinae composed of vestigial granules and of a tegumentary elevation; the most prominent are lateral external and ventral external carinae; inner side of manus has a dense and tiny granularity; the remaining intercarinal tegument is coriaceous; there are two smooth vestigial carinae over the fixed finger and the movable finger has a prominent basal tubercle. There are 16 or 17 denticle lines on movable finger and 13 to 15 denticle lines on fixed finger. Tibia: with a complete internal dorsal carina consisting of small, well-defined granules that are regularly aligned; a segmented external dorsal carina with granules aligned; an external dorsal carina segmented on distal half; granules on basal half are small and aligned; external lateral carina has abundant granules that are poorly defined; external ventral carina is lacking; internal ventral carina has granules of various sizes separated from each other; adjacent granules coalesce; an internal median carina formed by denticles of diverse diameters and heights that are larger on base; dorsal, ventral and lateral teguments are covered with dense, small granules that are better defined on inner side and around internal ventral carina. Femur: complete dorsal carinae with well-defined and aligned granules; a sinuous external median carina made up of small poorly-defined granules; external ventral carina is lacking; ventral internal carina has well-defined granules which diminish in size towards its distal end; external median carina is formed by denticles which are prominent but blunt; intercarinal tegument is densely and finely grainy.

FIGURE 1.
Tityus ivic-nancor n. sp. - Male

1a - Dorsal view of right pedipalp.

1b - External side of chela.

1c - Basal lamellae of pectens.

1d - Ventral side of caudal segments II-IV.

1e - External side of caudal segments II-V and telson.

Walking legs: carinae on femora and tibiae are made up of very small granules that are spiny on ventral side; intercarinal spaces have dense and small grains on femora but are scarce on tibiae; pre-tarses and basitarses have smooth carinae.

Tergites have a single medial longitudinal carina that is made up of a single grain on tergite I; carina is thicker in the middle on tergites II-VI and is broad and poorly defined on tergite VII; tergites I-VI exhibit a curved lateral carina with granules of diverse sizes, similar to those in posterior border of tergite; the remaining tegument is densely and finely grainy; tergite VII has two paramedian carinae which occupy the entire segment; tergite VII also has two sinuous lateral carinae and a thick transversal carina which joins lateral carinae by their proximal ends; granules on those carinae tend to be denticular; intercarinal tegument is densely and finely grainy. Sternites I-III are coriaceous; the latter has a smooth median posterior triangular area; there are vestigial granules on sides of sternites II and III and over the entire sternite IV; sternite V has four vestigial carinae, granules on lateral and posterior borders and a dense, fine intercarinal granularity.

Basal lamellae of the combs are shown in (Figure 1c). There are 17 to 20 pectineal denticles.

Caudal segments are short and thick; segments I-IV have prominent dorsal carinae with denticulate granules which grow in size towards distal end where they become a thick denticle; lateral dorsal and lateral ventral carinae are made up of granules of moderate size; external lateral carina is complete on segment I and granules are similar to their neigbors on segment; external lateral carina on segment II is vestigial on basal and medial thirds but appears as spaced granules on distal third of segment; ventral median carinae of segments I and II are double and slightly convergent on distal end; these carinae are also double on segment III but convergent on basal and median thirds of segment; there is only one thick carina on distal third of segment; there are two short carinae on basal third of segment IV, and a median carina that begins between the two short ones; intercarinal tegument of these segments is covered with abundant, small and vestigial granules; dorsal carinae of segment V are vestigial in the center and are replaced by four or five granules on their ends; ventral lateral carinae and ventral carina present small and spaced granules; ventral median furrow is coriaceous and the entire segment V has abundant vestigial granules. Telson: vesicle is almost ovoid and slightly curved on dorsum; sides and venter of vesicle are covered with vestigial granules; there are two lateral and two ventral furrows; the subaculeate tubercle has two dorsal granules; the aculeus is robust and short (see Figure 1d and Figure 1e).

DIFFERENTIAL CHARACTERISTICS OF FEMALES.

Carapace: anterior and posterior borders have dense and varied granulation; carinae have large and scarce granules that mingle with their neighbors; the remaining tegument has abundant and varied granules, especially in front of median ocular tubercle and on lateral posterior angles.

Pedipalps are shown in (Figure 2a). Chela is shown in (Figure 2b); it is almost ovoid with external dorsal carinae moderately prominent with small elongated granules; digital carina is segmented with an interruption in the middle of manus; very small grains fill the gap; external ventral carina is smooth, while internal ventral carina is vestigial; tegument is coriaceous on dorsal, external and ventral sides, on inner side there are abundant tiny granules; carinae on fingers are smooth; movable finger has 16 or 17 denticle alignments and fixed finger has 14 to 16 denticle alignments. Tergites: granules on carinae and on intercarinal tegument are larger and more abundant than in male specimens. Sternites: sternite IV is covered with small abundant granules that are larger on lateral and posterior borders; paramedian and lateral carinae on sternite V is well defined; there are large granules on lateral borders and small densely-packed granules on intercarenal tegument. Basal lamellae of the pectens are shown in (Figure 2c); there are 17 to 20 pectineal teeth. Caudal segments I-IV have dorsal and lateral carinae made up of denticular granules; granules on dorsal carinae terminate in a larger denticle; medial ventral carinae of segment I are parallel; on segment II, carinae are parallel up to the middle of the segment and then remain separated but tend to converge; on segment III, carinae are double and parallel up to the middle of the segment and become a single carina on the rest of it; on segment IV, carinae are double and irregular on basal third, and there is only one carina on the rest of the segment; dense, vestigial granulation covers the remaining tegument; on segment V, carinae are prominent, dorsal ones are clearly defined, intercarinal tegument has abundant and varied granules (see Figure 2d and Figure 2e). Table 1 lists the values of metrical characters.

FIGURE 2.

2a - Dorsal view of right pedipalp.

2b - External side of chela.

2c - Basal lamellae of pectens.

2d - Ventral side of caudal segments II-IV.

2e - External side of caudal segments II-V and telson.

TABLE 1. Metrical characters (Metrical measurements)
of male and female Tityus ivic-nancor n.sp. and Tityus sanarensis n.sp.

Tityus sanarensis n.sp.

Material examined: 9 male and 9 female adult specimens. They were all collected by Dr. Carlos D'Suze (Instituto De Biomedicina, Proyecto de Enfermedades Endémicas de Sanare, state of Lara, Venezuela).

Typical location: Near the town of Sanare (69º42'17.8"W, 9º45'3.9"N) in the southern part of the state of Lara, Venezuela.

Distribution: Below the Yacambú National Park, between the town of Sanare and the hamlets of La Cañada and Versalles, Jiménez District, state of Lara, Venezuela.

Habitat: Under rocks and in crevices of hilly roadsides; near high tropophilous forests and grassy lands, from 1300 to 1400 m above sea level.

Climate: Gwi of Koeppen.

Etymology:sanarensis = derived from the name of the town of Sanare, typical locality of the species.

Diagnosis:Tityus sanarensis n.sp. is distinguished by the following characteristics: a) marked sexual dimorphism on chelae; b) pedipalp chelae with a long ovoidal manus with long and slender fingers; c) caudal segments I-V are long, narrow and parallel; d) ventral carinae of segments II-IV are irregular e) telson is ovoid and long T. sanarensis n.sp. is closely related to Tityus carabobensis González-Sponga, 1987 (4). It may be differentiated from this species by the shape of chela, by the shape of basal lamellae of pectens and by telson. It may be differentiated from the species in its group that are geographically close such as T. falconensis (2), T. barquisimetanus (6), T. pococki (7), T. rugosus (10,11) and T. valearae (12) by the shape and length of pedipalp and of metasoma.

DESCRIPTION 2

CHARACTERISTICS OF MALE SPECIMENS.

Color: Pedipalps and walking legs are light brown and the remaining tegument is dark brown.

Carapace: anterior border is slightly obtuse; lateral borders are sinuous and posterior border is straight on sides and curves behind posterior marginal furrows; anterior paramedian carinae are sinuous and made up of very small closely-packed granules; supraciliary carina is made up of flat granules; posterior paramedian carinae are sinuous with inconspicuous and coalescent granules; anterior lateral carina has poorly-defined granules that are less prominent on distal end; anterior marginal carina is made up of very small granules that are well defined in front of anterior median furrow; on the sides of carina the granules are of irregular size and distribution; posterior marginal carina is composed of very small granules in the middle and of granules that are irregularly spaced on the sides; anterior median furrows are wide and shallow with very small and scattered granules; median ocular furrow is broad and shallow; posterior median furrow consists of three foveae of which the distal one is deeper; the furrow is flanked by some very small granules; posterior marginal furrows are short, broad, shallow and coriaceous; posterior lateral furrow is wide and shallow with vestigial granules in its depth and on its sides; median ocular tubercle is prominent; lateral ocular tubercles have vestigial granules on their dorsum. The rest of tegument is coriaceous and presents mostly irregularly distributed small granules; granules are more abundant on the lateral central area of carapace and between anterior paramedian and anterior lateral carinae.

Pedipalps: See Figure 3a. A Chela is shown in Figure 3b; manus is long and ovoid;dorsal carina is made up of vestigial granules clustered on basal half of manus; grains on distal carina are regularly aligned; external dorsal carina is made up of vestigial granules on its base, the rest of the carina is just an elevation of tegument; digital carina has abundant vestigial granules on its base; it is broken up in the middle by a gap filled with small granules and the rest is smooth; lateral median carina has vestigial granules that are less prominent towards distal end; external submedian carina is short, prominent and made of vestigial granules; external ventral carina is incomplete and made up of vestigial granules; the entire carinae on the fixed finger are smooth; intercarinal tegument is coriaceous on external and ventral sides and finely granular on inner side; there are 16 to 18 denticle lines on movable finger and 14 or 15 on fixed finger. Tibia: dorsal internal carina is poorly-defined and made up of scarce vestigial grains and is more prominent on distal end; dorsal median and external dorsal carinae are well defined and made up of regularly-spaced granules; external ventral carina is absent on basal half and vestigial as its granules on the remaining portion; internal ventral carina is vestigial and made up of irregularly-aligned granules; internal median carina is made up of spaced denticles of varying height and it has a basal denticle that is bigger and bifid; intercarinal tegument is coriaceous with very tiny vestigial granules. Femur: dorsal carinae are made up of granules of diverse sizes not well aligned; external median carina is prominent and made up of vestigial granules on basal half, and of denticular granules on distal half; external ventral carina is poorly marked and made up of small granules; internal median carina is prominent with obtuse pyramidal granules of diverse sizes; intercarinal tegument is covered with very tiny vestigial granules.

FIGURE 3.

3a - Dorsal view of right pedipalp.

3b - External side of chela.

3c - Basal lamellae of pectens.

3d - Ventral side of caudal segments II-IV.

3e - External side of caudal segments II-V and telson.

Walking legs: femora present four carinae; dorsal and lateral ones carinae are made up of granules small in heigh and of varied sizes; ventral carina is made up of denticles and intercarinal tegument is covered with flat granules of diverse sizes; prominence of carinae and abundance of granules increase progressively as one moves towards the hindmost legs; tibiae have prominent carinae made up of vestigial granules; tegument on carinae is coriaceous; pre-tarsus and basitarsus have smooth carinae on external side and very small denticles on inner side.

Tergites: there is a single medial longitudinal carina on tergites I-VII; it is made up of a single grain in tergite I; carina becomes longer and wider as one moves towards the hindmost tergites; tergites I-VI exhibit a curved and grainy central lateral carina; tergite VII has two paramedian carinae; on tergites I and II the granules of these carinae mingle with those on posterior marginal carinae; tergites I-VI have a line of granules of diverse size on posterior border; the remaining tegument is covered with abundant small granules which are even more abundant on posterior tergites; tergite VII has a broad median carina covered with vestigial granules of diverse sizes; paramedian carinae are curved and not prominent on both ends occupying the entire segment and connecting with lateral carinae by a broad and grainy keel; lateral carinae are incomplete and their grains are denticles; intercarinal tegument is covered with abundant small granules. Sternites I-III have broad and shallow granules on sides; the remaining tegument is smooth and irregular; sternite V has two long paramedian carinae and two short lateral ones made up of broad and stubby granules; none of these carinae reaches the anterior border of the segment; carinae on lateral borders are prominent with very small and spaced granules.

Basal lamellae of the combs: they are shown in Figure 3c. There are 15 or 16 pectineal denticles.

Caudal segments: segments I-V are long and slender; intercarinal tegument is coriaceous; dorsal, dorsal lateral and ventral lateral carinae are prominent; granules on dorsal carinae are small and spaced; distal granule of segments II-IV is bigger; lateral carinae are made up of broad and stubby granules; lateral median carina is absent; ventral carinae are not prominent and their granules are stubby; carinae are double and parallel on segment I and on proximal half of segment II, becoming convergent on distal half of segment II; these carinae are also double and parallel with small granules interspersed in the middle of segment III, but there is only one carina on distal third of segment; there is only one carina with some irregularly-distributed basal granules on segment IV; segment V is convex and lacks dorsal ornaments; dorsal carinae of segment V are merely present as a single line of small, well-defined and spaced granules; ventral lateral and ventral carinae are covered with stubby and well-spaced granules; intercarinal tegument on sides and on venter have vestigial granules. Telson is ovoid, long and its dorsum is coriaceous and lacks ornaments; lateral borders are curved; lateral and ventral furrows are broad; there are some ventral and lateral granules spaced and not prominent; the flattened subaculeate tubercle has a single dorsal granule and the aculeus is robust and short (Figure 3d and Figure 3e).

DIFFERENTIAL CHARACTERISTICS OF FEMALES.

Carapace: anterior paramedian carinae have prominent, irregularly-aligned granules of varied sizes; posterior paramedian carinae are well defined; there are large granules behind the median ocular tubercle; lateral and posterior lateral granules of carapace are poorly defined.

Pedipalps are shown in Figure 4a Chela is shown in Figure 4b; manus has well-defined granulose carinae; digital carina is incomplete without interruption in the center of manus but absent on the base of fixed finger; there are 16 or 17 denticles on movable finger and 14 or 15 denticles on fixed finger. Tergites have prominent carinae and grains; granules on intercarinal tegument are abundant. Sternite IV has two paramedian vestigial and small flattened granules placed between carinae and on sides; sternite V has poorly-defined carinae and small granules between them. Basal lamellae of the pectens are shown in Figure 4c; pectineal denticles are shown in Figure 3e, Figure 4a and Figure 4b. Caudal segments are short and robust; dorsal ventral carinae of segments I-IV are prominent and are made up of denticles that grow in size to become a single distal denticle; dorsal lateral and ventral lateral carinae are made up of moderately prominent and regularly-aligned granules; there is a complete external lateral carina on the segment I; this carina is replaced by a distal granule on segment II; ventral carinae are complete and parallel on segments I and II; there is one ventral medial carina with spaced granules on segment III and two paramedian carinae spanning half of this segment; segment IV has one medial ventral carina and a group of basal granules made up of clusters of two or three smaller and aligned granules; segment V is moderately long and has five carinae made up of stubby granules which are regularly aligned and spaced between them; external side of segment has some vestigial granules aligned where dorsal lateral carinae should have been; there are abundant vestigial granules on intercarinal space; female telson is shown in Figure 4d and Figure 4e; vesicle is moderately long, its dorsum is smooth and convex; there is a line of granules on dorsal border that becomes vestigial on distal end; there are also granules of diverse size on sides and venter. Table 1 lists the values of the metrical characters.

FIGURE 4.

4a - Dorsal view of right pedipalp.

4b - External side of chela.

4c - Basal lamellae of pectens.

4d - Ventral side of caudal segments II-IV.

4e - External side of caudal segments II-V and telson.

ACKNOWLEDGEMENTS

I would like to express my gratitude to Dr. Gina D'Suze and Dr. Carlos Sevcik of the Laboratory of Cellular Neuropharmacology at IVIC for their help and to Mrs. Dhuwia Otero-Palma for making ink copies of the figures. The manuscript was translated into English by Dr. Carlos Sevcik.

Received 16 October 1996

Accepted 16 November 1996

References

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CORRESPONDENCE TO:

M. A. GONZALES-SPONGA - IVIC CBB, Apartado 21827, Caracas 10 20 A, Venezuela.

Publication Dates

• Publication in this collection
  13 July 1999
• Date of issue
  1997

History

• Received
  16 Oct 1996
• Accepted
  16 Nov 1996