Heteronebo portoricensis Francke, 1978

Teruel, Rolando, Rivera, Mel J. & Sánchez, Alejandro J., 2017, The scorpion fauna of Mona Island, Puerto Rico (Scorpiones: Buthidae, Scorpionidae), Euscorpius 250, pp. 1-15 : 12-14

Heteronebo portoricensis Francke, 1978

( Figure 7)

Heteronebo sp. : Armas, 2005: 73; fig. 8. Teruel et al., 2015: 13.

DISTRIBUTION. This species is confirmed to occur only in Puerto Rico and immediately offshore satellite islets such as Magueyes and Caja de Muertos. The single known specimen allegedly from Mona Island was most likely collected in mainland Puerto Rico and inadvertently mislabeled (see below in Remarks section).

PRIMARY MATERIAL EXAMINED (1 specimen). Puerto Rico, Mayagüez Municipality, Mona Island [likely wrong locality, see below in Remarks section], September/2000, under rock, J. L. Fontenla, 1 juvenile ♂ ( IES) .

COMPARATIVE MATERIAL EXAMINED (37 specimens: 5♂♂, 24♀♀, 7 juveniles, 1 first-instar). Puerto Rico, Sabana Grande Municipality, Susúa, 200 m a.s.l., 3/October/2000, O. H. Garrido, J. A. Genaro, A. Pérez- Asso, 2♀♀, 1 juvenile ( IES) . 10/July/2005, under rocks, humid montane forest, A. Sánchez, 2♀♀ ( RTO: Sco- 0377). Yauco Municipality , Guayanilla, Punta Verraco, 10 m a.s.l., December /1999, J. A. Genaro, 1♀, 1 juvenile ( IES) . 16/July/2010, under rocks, dry subcoastal forest, L. F. de Armas, A. Pérez-Asso, 1♂, 1♀ ( RTO: Sco-0479). Guánica Municipality , Guánica, 75 m a.s.l. , 22/August/1995, G. Alayón, 1♂, 1♀, 1 juvenile ( IES) . 26/February/2001, under rocks, dry coastal forest, A. Sánchez, 2♀♀ ( RTO: Sco-0020). November /2002, under rock, dry coastal forest, A. Sánchez, 1♂ ( RTO: Sco-0216) . 13/October/2003, under rock, dry coastal forest, A. Sánchez, 1♀ ( RTO: Sco- 0239) . 25/March/2004, under rock, dry subcoastal forest, A. Sánchez, 1♀ ( RTO: Sco-0238) . 31/July/2004, under rocks, dry subcoastal forest, A. Sánchez, 1♂, 2♀♀, 2 juveniles, 1 first-instar ( RTO: Sco-0261) . 18/February/2012, under rocks, dry subcoastal forest, A. Sánchez, 6♀♀ ( RTO: Sco-0540). Ponce Municipality, Real Arriba , 22/August/1995, under rocks, A. Ruiz- Baliú, 1♀, 1 juvenile ( RTO: Sco-0021). Caja de Muertos Island , 24/July/2010, under rocks and fallen log, xerophytic scrub, L. F. de Armas, A. Pérez-Asso, 2♀♀, 1 juvenile ( IES) . 10/February/2012, A. Sánchez, under rocks, xerophytic scrub, 1♂, 2♀♀ ( RTO: Sco- 0 541) .

REMARKS. Armas (2005: 73) regarded the single specimen from Mona Island as an immature male of an undetermined species similar to Heteronebo portoricensis , and cited the lack of punctations from sternites and telson as a diagnostic character. Ten years later, Teruel et al. (2015: 13) examined the same specimen and concurred with Armas (2005). Nevertheless, the detailed study of additional specimens of Heteronebo portoricensis revealed that this difference is due to immaturity: two same-sized juvenile males (apparently subadults) from Guánica and Ponce also lack punctations in the same cuticular surfaces.

On the other hand, we strongly suspect that this specimen of Heteronebo portoricensis and the holotype of Cazierius garridoi were accidentally swapped during the sorting or mailing process and thus, that the correct origins are Cerro de Punta for the former and Mona Island for the latter. According to their original label data (see above) and supplementary information provided by Luis F. de Armas (personal communication to RT), both specimens were collected during a field trip conducted by the same team to both islands, and later given to him in separate batches. Additional evidences give overwhelming support to the mislabeling hypothesis:

First, Cazierius garridoi is the only diplocentrine confirmed to occur in Mona Island and has been repeatedly found by multiple, independent collectors including our team. As opposite, no other specimens of the genus Cazierius have been found in mainland Puerto Rico, despite long-term and intensive searches for many years (including continued searches by our team at Cerro de Punta and nearby areas).

Conversely, no other specimens of the genus Heteronebo have been found in Mona Island, despite recurrent and intensive searches by our team and other collectors. But Heteronebo portoricensis is widespread across mainland Puerto Rico (where it has been repeatedly found by multiple, independent collectors including our team), and was already recorded from Adjuntas ( Francke, 1978: 45), a mountainous locality near to Cerro de Punta.

Last, the present study revealed that the scorpion fauna of Mona Island is a detached, impoverished fragment of that of easternmost Hispaniola, i.e., essentially all species are shared between both territories ( Centruroides bani , Heteroctenus abudi and possibly also Cazierius cicero ). And again, the genus Heteronebo is conspicuously absent from eastern half of Hispaniola ( Armas, 1988, 1999, 2001; Teruel, 2005; Teruel, Armas & Kovařík, 2015b).

General Remarks

The present revision sets the scorpion species confirmed to occur at Mona Island to three: two buthids of the closely-related genera Centruroides and Heteroctenus and one diplocentrine scorpionid of the genus Cazierius . This is the standard composition for coastal localities of the Greater Antilles (R. Teruel, unpublished), but rather poor due to the apparent absence of other buthid genera such as Microtityus and Tityus , both of which occur in similar landscapes of both coasts directly facing Mona Island (easternmost Hispaniola and westernmost Puerto Rico). In comparison with these adjacent areas, also at least a second species of Centruroides and maybe a troglobite could still be discovered in this island because it cannot be regarded yet as satisfactorily sampled, especially its extensive cave systems.

This contribution does not alter the number of species compiled in the most recent catalogue of the Puerto Rican scorpion fauna (Teruel, Rivera & Santos, 2015), but clarifies the identity of those occurring in Mona Island. Nevertheless, an important update has been made: the endemism (excluding the Virgin Islands) has now decreased from 82% to less than 74% and is expected to drop even more, if the suspected synonymies of Cazierius garridoi and two other species of Centruroides are confirmed (Teruel, Rivera & Santos (2015: 12)).