Charinus martinicensis, Teruel & Coulis, 2017

Teruel, Rolando & Coulis, Mathieu, 2017, First record of the genus Charinus Simon, 1892 from Martinique, Lesser Antilles, with description of a new species (Amblypygi: Charinidae), Ecologica Montenegrina 13, pp. 30-36 : 31-35

Charinus martinicensis , new species

Figures 1–4 . Table I

TYPE DATA. MARTINIQUE: Sainte-Anne : Morne Manioc (14°26'00"N – 60°51'26"W, 150 m a.s.l.); 27/May/2017; M. Coulis; 1♀ holotype ( RTO), 1♀ paratype ( RTO) . Same data, except: 30/August/2016; 2♀♀ paratypes ( RTO) .

ETYMOLOGY. The selected specific epithet is a Latinized adjectival name derived from the toponym of the island where this species is known to occur.

DIAGNOSIS (females only). Adult size medium to moderately large (3.9–6.7 mm) for the genus. Coloration immaculate olivaceous brown, with median and lateral ocular tubercles black. Carapace with all three ocular groups and their respective tubercles fully developed; frontal area widely convex. Tritosternum/tetrasternum/pentasternum with 3–2/2–1/1 pairs of spiniform macrosetae, respectively; tritosternum with a pair of apical spiniform setae. Leg I flagellum with 23 tibial and 37 tarsal segments. Leg IV basitibia either trisegmented or bisegmented. Tarsomere II of legs II–IV with translucent membranous ring complete.

DESCRIPTION (adult female holotype). Coloration (fig. 1) uniformly olivaceous brown, slightly paler on venter and darker on carapace and pedipalps. Chelicerae reddish. Intersegmental membranes whitish. Carapace with median and lateral ocular tubercles blackish.

Chelicerae (figs. 2a–b) with dentition standard for the genus: ventrointernal edge of manus with four teeth, the distalmost bicuspid with apical cusp longer.

Pedipalps (figs. 2a–b) not attenuated, tegument minutely wrinkled, completely devoid of granules but with abundant spiniform setae in all segments, much stronger on trochanter and femur. Trochanter moderately covered with large spiniform setae, with one anterodorsal spine (long, sharp and sinuose); ventroapical spur large, thick and with tip very sharp and curved inwards. Femur with three dorsal spines (Fd-1> Fd-2> Fd-3, all subdivided by sutures), flanked externally by an oblique irregular row of 11–13 large setiferous tubercles and heavy spiniform macrosetae (stronger basally); ventrally with three spines (Fv-1> Fv-2> Fv-3), plus five mostly small spiniform setae. Patella moderately flat; dorsally with three very large spines (Pd-1 <Pd-2 <Pd-3, none subdivided by sutures), plus a very large spine-like setiferous tubercle distal to Pd-3 (actually a modified Pd-4, slightly shorter than Pd-1); ventrally with two spines (Pv-1 about half the length of Pv-2, none subdivided by sutures) and about 11 spiniform setae irregularly arranged into two longitudinal rows. Tibia markedly flat; dorsally with two spines (Td-1 half the size of Td-2, none subdivided by sutures); ventrally with one spine (Tv-1), which is of similar size to Fv-1 and Pd-2 and not subdivided by any suture. Tarsus dorsally with two spines (Bd-1 almost three times shorter than Bd-2, none subdivided by sutures); ventrally smooth, with cleaning organ very long, closely barbed and distally stronger. Claw long, sharp, evenly curved inwards and smooth; membranose division between tarsus and postarsus well defined, but undulate (i.e., not circular).

Carapace (fig. 2c) widely cordiform, 1.29 times wider than long. Tegument minutely wrinkled, but otherwise completely devoid of granules and with a few minute setae symmetrically scattered on medial region. Frontal margin wide and markedly convex (widely protruded), with three pairs of spiniform setae; posterior margin with eight pairs of minute spiniform setae. Median eyes well-developed, median ocular tubercle strong but located inside a deep oval depression of the tegument, underlying melanic pigment fully developed; lateral eyes well developed but unpigmented, entirely translucent-white, lateral ocular tubercles well developed, with underlying melanic pigment fully developed.

Tergites (fig. 1a). With the same sculpture and setation as on carapace.

Ventral region (figs. 1b, 2e,g–h). Tritosternum long and apically narrow (vestigially bottleshaped), with two apical macrosetae plus two pairs of slightly smaller spiniform macrosetae (median and sub-basal), an additional basal pair smaller and thinner, and five spiniform microsetae irregularly arranged around basal part. Tetrasternum moderately sclerotized, wider than long and with a large median pair of spiniform macrosetae plus a much smaller basal pair of spiniform microsetae. Pentasternum moderately sclerotized, wider than long and with a large median pair of spiniform macrosetae plus a minute basal pair of spiniform microsetae. Metasternum weakly sclerotized, wider than long and with a pair of large spiniform setae. Sternites smooth, moderately covered by short, thin setae; genital operculum large, with posterior margin widely rounded.

Legs (figs. 1a–b) slender but not unusually attenuated, femur sparsely covered with minute scalelike tubercles and spiniform setae of various sizes. Right leg I flagellum with 23 tibial and 37 tarsal segments, first tarsomere about twice as long as second; left leg flagellum missing. Leg IV basitibia trisegmented (left) or bisegmented (right). Tarsomere II of legs II–IV with the translucent membranous ring complete, representing a true tarsal subdivision.

MALE. Unknown.

VARIATION. The three paratype females are adult, but conspicuously smaller (tab. I) and paler than holotype. Such size variation is common in amblypygids, because there is no terminal ecdysis, i.e., individuals never stop molting and growing during their entire lifetime. Concurrently, the width/length ratio of carapace varies from 1.25–1.28 amongst paratypes.

All four type-specimens have minor anomalies in pedipalp spination. The most extreme case is the largest paratype, which exhibits right Fv-2 folded from base, right Pd-2 folded distally, left Pv-2 folded from base, left Td-1 missing and left Bd-2 doubled. Moreover, the smaller paratypes have pedipalps with setation fewer and sparser.

Two of the three paratypes have leg I flagellum with the same segmentation as holotype: 23/23 tibial and 37/37 tarsal segments. The remaining specimen has 23/21 tibial and 32/39 tarsal segments, with tarsal part of left leg and complete right leg showing clear evidence of regeneration, i.e., many segments are much shorter than normal.

Segmentation of leg IV basitibia exhibits interesting variations amongst paratypes. The female collected in 2017 has right basitibia fully trisegmented but left basitibia partially trisegmented (basalmost division only involves dorsal half). Both paratypes collected in 2016 have fully trisegmented basitibia.

The number of spiniform setae of tritosternum/tetrasternum/pentasternum is also variable. The paratype collected in 2017 has 3/1/1 pairs (plus 6/2/0 basal microsetae), while both paratypes collected in 2016 have 3/2/1 pairs (plus 5/2/1 basal microsetae) and 2/1/1 (with 2/0/0 microsetae), respectively.

The coloration described above corresponds to freshly preserved specimens. In live individuals it is moderately darker, with a satin sheen due to the presence of the same cerotegument recently described for other amblypygids ( Wolff et al., 2016).

COMPARISONS. The presence of fully developed median eyes and ocular tubercle makes this new species very easy to distinguish from all other Antillean described congeners, except Charinus acosta ( Quintero, 1983) , Charinus bruneti Teruel & Questel, 2011 , and Charinus victori Armas, 2010 , three insular endemics from Cuba, Saint-Barthélemy and Puerto Rico, respectively. But the differences in modal count of tibial/tarsal segments of leg I flagellum are clearly diagnostic: 23/ 37 in C. martinicensis sp. n., 23/ 41 in C. acosta , 22/ 39 in C. bruneti , and 21/ 33 in C. victori .

DISTRIBUTION (fig. 4). This species is known only from the type locality, in the low calcareous karstic hills (= " mornes ") of southern Martinique, in the Windward Islands of the Lesser Antilles .

ECOLOGICAL NOTES. All specimens were found hanging to the underside of limestone rocks (fig. 3a), semi-buried in the deep leaf litter of the coastal semicaducifolious forest (fig. 3b).

REMARKS. One paratype collected in 2016 has right leg I flagellum detached, but it is stored in the same vial as the specimen. The other paratype from the same date has right leg II flagellum missing.

Both paratypes collected in 2016 have the median area of sternite II with an irregularly-sculptured, raised area that blocks the genital operculum from being lifted. It is most likely a teratology derived from a disease or accident, because the operculum is completely normal in the holotype and paratype collected in 2017.

With this addition, the list of the Antillean charinid amblypygids is raised to 15 species:

1. Charinus acosta ( Quintero, 1983) : Cuba.

2. Charinus bahoruco Teruel, 2016 : Hispaniola

3. Charinus bruneti Teruel & Questel, 2011 : Saint-Barthélemy.

4. Charinus caribensis (Quintero, 1986) : Jamaica.

5. Charinus centralis Armas & Ávila, 2001 : Cuba.

6. Charinus cubensis ( Quintero, 1983) : Cuba.

7. Charinus decu ( Quintero, 1983) : Cuba.

8. Charinus desirade Teruel & Questel, 2015 : Guadeloupe.

9. Charinus dominicanus Armas & Pérez, 2001 : Hispaniola.

10. Charinus martinicensis Teruel & Coulis, 2017 : Martinique.

11. Charinus muchmorei Armas & Teruel, 1997 : Virgin Islands.

12. Charinus perezassoi Armas, 2010 : Puerto Rico.

13. Charinus tomasmicheli Armas, 2006 : Cuba.

14. Charinus victori Armas, 2010 : Puerto Rico.

15. Charinus wanlessi ( Quintero, 1983) : Cuba.

Nevertheless, this list is by no means complete. At least five undescribed species are already known from Cuba, Hispaniola and The Grenadines ( Armas, 2006; Teruel & Questel, 2015; R. Teruel, unpublished data), and more additions are expected as other islands of the Antilles become better sampled for these tiny amblypygids. For example, when the present paper was already submitted to press, new fieldwork in another site of Martinique yielded specimens of a different, second species of Charinus , which is currently being studied by us (R. Teruel & M. Coulis, in preparation).

Figures

Figure 1. Adult female holotype of Charinus martinicensis sp. n., full-body views: a) dorsal; b) ventral. Scale bar: 5 mm.

Figure 2. Adult female holotype of Charinus martinicensis sp. n., close-ups: a) chelicerae and pedipalps, dorsal; b) chelicerae and pedipalps, ventral; c) carapace, dorsal; d) chelicerae and frontal area of carapace, dorsal; e) sternal area, ventral; f) abdomen, dorsal; g) abdomen, ventral; h) sternites I–IV, ventral. Scale bars: 2 mm (a–b), 1.5 mm (c–d, f–g), 1 mm (e–h).

Figures 3-4. 3 Adult female paratype of Charinus martinicensis sp. n.: a) photographed alive upon finding; b) natural habitat. 4 Map showing with black squares: a) known geographical distribution of the genus Charinus in the Antilles, including unpublished records from Cuba and Hispaniola by the present author; b) type locality of Charinus martinicensis sp. n.