The description of Tityus caripitensis. A new venezuelan scorpion (scorpionida, buthidae)

Original paper

The description of Tityus caripitensis. A new venezuelan scorpion (scorpionida, buthidae)

M. QUIROGA¹, L. DE SOUSA², P. PARRILLA-ALVAREZ¹

1 Laboratorio de Alacranología, Escuela de Medicina, Universidad de Oriente, Núcleo de Bolívar, Ciudad Bolívar, Venezuela; 2 Grupo de Biomedicina Aplicada (GBA), Centro de Investigaciones en Ciencias de la Salud (CICS), Universidad de Oriente, Núcleo de Anzoátegui, Puerto La Cruz, Venezuela.

ABSTRACT. This paper describes a new species of scorpion of the Tityus genus, Tityus caripitensis (Scorpionida: Buthidae). This species can be found in Caripito, Bolívar municipality of Monagas State, Venezuela. The number of species of Tityus genus in Venezuela has increased to 37 with the inclusion of Tityus caripitensis. A diagnosis of the most significant morphological characteristics of both males and females of this new species, which has been causing serious envenomings in the Bolívar and Punceres municipalities, has been carried out.

KEY WORDS: scorpion, Tityus, new species, Venezuela.

INTRODUCTION

There are four families of scorpions in Venezuela: Buthidae, Chactidae, Diplocentridae, and Scorpionidae (8), which up to 1999 include 19 genera and 122 species (6-12). The Buthidae has the widest distribution in Venezuela (8). This family includes the Tityus genus, which has species of medical (1) and epidemiological (14,16) importance.

In Monagas State, particularly in the north central region, the Bolívar, Caripe, Cedeño, and Piar municipalities have been identified as endemic areas and Acosta as a hyperendemic area for scorpion envenoming (2,15). The Punceres municipality has also recently been identified as a new hyperendemic area in this State, with an incidence rate of 25 cases per 10,000 inhabitants in 1996 (3). The Bolívar municipality showed an incidence rate of 14.5 cases per 10,000 inhabitants in the same year (3). The ethiological participation of the Tityus genus in some severe envenomings has been confirmed in Bolívar and Punceres (16 ), as described in this paper.

DESCRIPTIONS

Tityus caripitensis n. sp.

MATERIAL EXAMINED. 130 specimens, 25 males and 105 females, were collected in Caripito (Bolívar municipality) and El Limón de Quiriquire (Punceres municipality) of Monagas State between 1985 and 1988 by Mercedes Quiroga, Alejandro Illanes, Adom González, and Leonardo De Sousa. These specimens are now stored in the "Colección de Escorpiones del Laboratorio de Alacranología" (CELA), Escuela de Medicina, Núcleo de Bolívar, Universidad de Oriente, Ciudad Bolívar, Venezuela. The specimens used in this description are registered under the following numbers: Females, CELA-0071 to 0100, CELA-0151 to 0170, and CELA-0176 to 0230; Males, CELA-0101 to 0120, and CELA-0171 to 0175.

TYPICAL LOCATION. Caripito (63º05´ W and 10º08´ N), Bolívar municipality, Monagas State, Venezuela (Figure 1a and Figure 1b).

FIGURE 1.
Distribution and typical location of Tityus caripitensis n. sp.

DISTRIBUTION. In the northeast of the Monagas State, including the municipalities of Bolívar (from 63º01´ W to 63º13´ W and 10º05´ N to 10º13´ N) and Punceres (from 62°56´ W to 63°20´ W and 9°53´ N to 10°08´ N) (Figure 1a and Figure 1b).

HABITAT. Tropical thermal floor with precipitation from 1,200 to 2,400 mm, consisting of the tropical dry forest and pre-mountainous humid forest with an annual mean bio-temperature higher than 24ºC, and an altitude between 40 and 120 meters above sea level.

MICROHABITAT. In rainy season, in the bark of trees and decomposing trunks; in the dry station, in trunks of Sabal palms (Palmaceae) and copra deposits.

CLIMATE. Type A (rainy warm): Ami.

ETYMOLOGY. caripitensis derived from the name of the town of Caripito, the typical locality of this species.

DESCRIPTION 1

CHARACTERISTICS OF FEMALE SPECIMENS. Total length, 75 mm; length of carapace, 7.60 mm; color, generally dark brown (Figure 2a).

FIGURE 2.
Tityus caripitensis n. sp. a. Female. b. Male.

CHELA. Denticles, 17 rows.

CARINAE. Dorsal; evident starting from the basal third with slightly conspicuous rounded granules. Internal dorsal; complete, with flat elongated granules in the first third and spaced, small, and barely evident granules in the other thirds. Digital; in the first third evident granules some of them elongated, absence of granules in the middle third, and then small flat granules up to the base of the fixed finger, where it is interrupted. External median; marked and complete. External sub-median; present only in the proximal half, evident and with small separated elongated granules. External ventral; evident with some granules in the basal third. Internal ventral; granules in the basal third.

TRICHOBOTRIA. The trichobotria of the immobile finger of the chela are arranged as follows: two dorsal trichobotria – db and dt, and four external - eb, esb, est, and et. The hand has two groups of external trichobotria; proximal ones - Eb1, Eb2, and Eb3, distal ones - Esb, Est, and Et (Figure 3a), and two ventral - V1, V2 (Figure 3b). In the tibia there are five dorsal - d1, d2, d3, d4, and d5, one internal - i, and seven external distributed in areas - 2=eb, 2=esb, 1=em, 1=est, and 1=et (Figures 4a, 4b). In the femur there are five dorsal trichobotria - d1, d2, d3, d4, and d5, four internal - i1, i2, i3, and i4, and two external - e1, and e2 (Figures 5a, 5b). The general tegument is coriaceous.

FIGURE 3.
Tityus caripitensis n. sp. Right chela. Female: a. Dorsal view (10x16). b. Ventral view (10x16). Male: c. Dorsal view (16x10). d. Ventral view (16x10).

FIGURE 4.
Tityus caripitensis n. sp. Right tibia. Female: a. Dorsal view (40x10). b. Ventral view (10x40). Male: c. Dorsal view (16x10). d. Ventral view (16x10).

FIGURE 5.
Tityus caripitensis n. sp. Right femur. Female: a. Internal view (40x10). b. Dorsal view (10x40). Male: c. Dorsal view (16x10). d. Internal view (16x10).

PECTINAL DENTICLES. In the females the number of pectinal denticles is a constant 19; in the males some variation is observed, between 18 and 21 (Figures 6a, 6b).

FIGURE 6.
Tityus caripitensis n. sp. Sternon, genital operculum, and combs. Female: a (16x10). Male: b (16x10).

CAUDAL SEGMENTS. The dorsal carinae of segment I are formed by very marked and rounded granules, the terminal is more conspicuous. The intracarenal tegument with small granules, some dispersed, others forming a V that begins with some of a small size and then, toward the vertex, they become more evident. In segment II, they increase in size up to the well-marked terminal. This progression is observed in segments III and IV. The intracarenal tegument of segments II and III show an arrangement similar to that observed in segment I. In segment IV there is an accentuated concavity in the anterior half, with coriaceous tegument and disparate slightly evident granules (Figure 7a). In segment V, the dorsal carinae are less marked, with slightly conspicuous and rounded granules. The intracarenal tegument is coriaceous with small and slightly marked granules (Figure 7a). The lateroventral carinae have big granules rather flat and elongated. This arrangement is similar to that of segments I to III, in segment IV they become more spaced and slightly smaller. This tendency continues into segment V. Lateral median carinae; double and parallel in segments I and II. In segment III, double and parallel in the two basal thirds, convergent in the distal third, although they separate again towards the end. Segment IV shows double carinae in the basal third, and a single carina on each of the two distal thirds (Figure 7b). In general, the granules are big and rounded. Segment V shows a single carina, with big flat granules on a coriaceous tegument with small abundant granulation (Figure 9). The telson is also coriaceous and granular, with a single furrow marker on each side. The dorsum shows minimum granulation, a big subaculear tubercle, and two dorsal spiniform granules. The lateral regions of the metasoma are coriaceous and granular (Figure 9).

FIGURE 7.
Tityus caripitensis n. sp. Female: Caudal segments. a. Dorsal view (10x16). b. Ventral view (10x16).

DESCRIPTION 2

CHARACTERISTICS OF MALE SPECIMENS. Total length, 91 mm; length of carapace, 7.10 mm; color, light brown (Figure 2b).

CHELA. Denticles, 17 rows.

CARINAE. Dorsal; thin with small and marked granules like points darker in color than the tegument. Internal dorsal; starting with flat granules, the same color as the tegument and continuing dark with little points. Digital; dark separated points. These points disperse in the median third, and then continue again aligned to the base of the fixed finger, where they are interrupted. External median; more marked than the digital carinae with granules like dark points. It is interrupted at a third of the way along the base of the mobile finger. External sub-median; only in the proximal third, a little sinuous with small tubercles, the same color as the tegument. External ventral; complete, without evident granules. Internal ventral; very slightly marked. The general tegument is slightly coriaceous.

TRICHOBOTRIAE. The trichobotriae of the immobile finger of the chela are arranged as follows: two dorsal – db and dt, and esb and eb are present; the two upper external are absent. The hand has two groups of external trichobotriae: the proximal ones - Eb1, Eb2, and Eb3, and the distal ones - Esb, Est, and Et (Figures 3c, 3d). In the tibia they are located as follows: d3, d4, and d5; the internal – i is present; and the external - 2=eb, 1=esb, 2=em, and 1=et (Figures 4c, 4d). In the femur there are five dorsal trichobotriae: d1, d2, d3, d4, and d5; four internal - i1, i2, i3, and i4; and only one external - e2 (Figures 5c, 5d).

PECTINAL DENTICLES. The number of denticles varies between 18 and 21 (Figure 6b).

CAUDAL SEGMENTS. The dorsal carinae of segment I are formed by evident flat granules of uniform size and slightly more marked in their distal part. The intercarenal tegument is lightly coriaceous with small and dispersed granules. In segments II and III, the granules of the carinae have spiniform tendency, the distal granule is conspicuous. They further apart than in the carinae of segment I (Figure 8a). The intercarenal tegument is the same as that of segment I. Segment IV shows carinae with more separate granules, with the distal more evident and spiniform. The intercarenal tegument with a concave furrow in all its length is less evident in its distal portion. The V with not very accentuated carinae and rounded granules in its base is barely visible in the midle portion and slightly marked in its terminal portion. The intercarenal area shows coriaceous tegument and a discreet furrow. Lateral carinae; only one medial in segment I. Ventral carinae; double and parallel in segments I and II; double and parallel in the basal two thirds of segment III, and a single one in the distal third. Segment IV shows double, parallel carinae in the proximal third and a single and straight at the end (Figure 8b). Segment V shows coriaceous dark tegument, with a single and not very evident medial carinae. The telson presents a coriaceous, more or less smooth dorsum, with the rest being granular with lateral furrow. There is a well-marked subaculear tubercle and a couple of conspicuous dorsal granules, which are not spiniform (Figure 10). In a lateral view, the sequence of the size of the segments can be seen, the proximal being shorter and the distal longer (Figure 10).

FIGURE 8.
Tityus caripitensis n. sp. Male: Caudal segments. a. Dorsal view (10x16). b. Ventral view (10x16).

FIGURE 9.
Tityus caripitensis n. sp. Female. Caudal segments with telson. Lateral view (10x16).

FIGURE 10.
Tityus caripitensis n. sp. Male. Caudal Segments with telson. Lateral view (10x16).

DISCUSSION

The scorpions of the Tityus genus described in Venezuela include three species that show similar characteristics in the ventral carinae. T. falconensis (4), T. monaguensis (4), and T. zulianus (5) have ventral carinae (vestigial or present) along segments I and II, and on segment III, these carinae are double and parallel in the basal half, and then they become a single line. T. caripitensis shows the same arrangement of its ventral carinae.

T. monaguensis, T. arellanoparrai, T. surorientalis, T. nororientalis, and T. tamayoi (7,8) can also be found in the same area as T. caripitensis in the northeastern region of Venezuela.

In this area, the nearest species to T. caripitensis is T. monaguensis. The distribution of T. monaguensis seems to have been up until now restricted to the caves and the areas around then in Caripe municipality, Monagas State (4). Our species has never been captured in caves or in the areas around them.

From the morphological point of view, T. caripitensis differs from T. monaguensis in the following ways: 1. In the chela, the secondary sub-exterior carinae reach as far as the trichobotrium Eb1. 2. The dorsal carinae has well-marked and rounded granules, without spiniform tendency. 3. The medioventral carinae in segment III are double and parallel up to more than halfway, then they converge and separate at the end. In segment IV, they are double and parallel in the first third and single in the remaining two thirds. In segment V, the medial carina is evident and the coriaceous tegument has abundant and small granules. 4. The telson shows the dorsum with a minimum granulation and coriaceous tegument.

The data on morbidity by scorpion envenoming in north central region of Monagas State (2,3,15,16) further confirm the importance of Tityus caripitensis, since in 1993, the mortality rate due to envenoming by this species in the Bolívar municipality was 3.48 deaths per 100,000 inhabitants (13). These epidemiological data reinforce the importance of this new species.

ACKNOWLEDGEMENTS

We express our gratitude to Professor Manuel Angel González-Sponga for allowing us access to his scorpion collection and for his guidance on the systematic of these arachnids, and to Professor Víctor Castro (INDESA, UDO) for his help in the digitalizing of the images. This work was co-financed by FUNDACITE-GUAYANA, FUNDACITE-ANZOÁTEGUI, and the Consejo de Investigación, Universidad de Oriente (CI-02-09-00126/77-87 M. Q. and CI-1-0403-0799/97-99 L.D.S.).

REFERENCES

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Received 08 March 1999

Accepted 09 June 1999

Publication Dates

• Publication in this collection
  25 Feb 2000
• Date of issue
  2000

History

• Accepted
  09 June 1999
• Received
  08 Mar 1999