Paraparatrechina illusio, LaPolla, John S. & Fisher, Brian L., 2014

LaPolla, John S. & Fisher, Brian L., 2014, Two new Paraparatrechina (Hymenoptera, Formicidae) species from the Seychelles, with notes on the hypogaeic weissi species-group, ZooKeys 414, pp. 139-155 : 141-144

Paraparatrechina illusio sp. n. Figs 1-9

Holotype worker.

SEYCHELLES: Praslin Island, 280m, 4.34725°S, 55.74743°E, 6.ii.2010, mixed palm forest, on low vegetation, B.L. Fisher et al. CASENT0159099 (CASC); 5 paratype workers, SEYCHELLES: Conception Island, 65 m, 4.66311°S, 55.36821°E, 12.ii.2010, mixed forest, B.L. Fisher et al. CASENT0160297 (CASC), CASENT 0160331 (CASC), CASENT0160622 (USNM), CASENT0160625 (CASC), CASENT0160650 (CASC); paratype worker, SEYCHELLES: Curieuse Island, 5 m, 4.28364°S, 55.7269°E, 4.ii.2010, coastal scrub, B.L. Fisher et al. CASENT0160122 (CASC); paratype worker, SEYCHELLES: Praslin Island, Newcome, 130m, 4.390°S, 55.6926°E, 6.ii.2010, palm forest, B.L. Fisher et al. CASENT0158991 (USNM); paratype worker, SEYCHELLES: Sillhouette Island, 20 m, 4.49076°S, 55.25341°E, 21.i.2010, coastal scrub, B.L. Fisher et al., CASENT0159838 (CASC).

Worker diagnosis.

Short, decumbent pubescence present lateroanteriorly around eyes; pubescence on gaster shorter, tightly appressed to gaster, with pubescence appearing in neat rows with a silky appearance.

Compare with: Paraparatrechina gnoma , Paraparatrechina oreias , and Paraparatrechina subtilis .

Worker.

Measurements (n=8) TL: 1.20-1.67; HW: 0.35-0.38; HL: 0.39-0.42; EL: 0.10-0.11; SL: 0.37-0.40; PW: 0.23-0.26; WL: 0.41-0.44; GL: 0.39-0.81

Indices: CI: 86-95; REL: 25-27; SI: 101-112.

Yellow to brownish-yellow; legs and antennae lighter; short, decumbent pubescence present lateroanteriorly around eyes; pubescence on gaster short, tightly appressed to gaster, with pubescence appearing in neat rows with a silky appearance. Head subquadrate with nearly straight posterior margin; scapes surpass posterior margin by first 2-3 funicular segments; three ocelli apparent. Mesosoma compact with steeply rising pronotum in lateral view; metanotal area indistinct, only slightly impressed; propodeum with short, flat dorsal face and much longer, steep declivitous face.

Queen.

Measurements (n=3) TL: 2.92-3.23; HL: 0.54-0.55; HW: 0.58-0.61; EL: 0.20-0.21; SL: 0.53-0.53; PW: 0.62-0.66; WL: 0.97-1.03; GL: 1.34-1.70

Indices: CI: 110-111; REL: 36-38; SI: 86-88

As in worker, with modifications expected for queen caste and the following differences:

Pubescence distinctly across head and mesosoma.

Gaster darker (yellowish-brown) than remainder of body.

Male.

Measurements (n=1) TL: 1.55; HL: 0.33; HW: 0.38; EL: 0.18; SL: 0.31; PW: 0.29; WL: 0.54; GL: 0.68

Indices: CI: 113; REL: 53; SI: 81

Head brown, with bulging large eyes that occupy most of the lateral region of the head; head slightly broader than long. Palps distinctly lighter than head in color. A dense layer of pubescence covers head, with scattered erect setae along mid-region, posterior margin and clypeus. Scapes surpass posterior margin by about length of the first 2 funicular segments; antennae 13-segmented. Mandible with apical tooth and an indistinct basal angle. Mesosoma same color as head; pronotum short and collar-like; mesonotum large, rounded anteriorly, overarching pronotum; mesosoma dorsum flat, with erect setae. Gaster slightly ligher brown than head and mesosoma, covered with pubescence and erect setae. Parameres relatively broad then with a steep angle towards last third of paramere length; last third of paramere thinner and elongated with rounded apex; paramere with scattered erect setae.

Notes.

This species falls into the small, yellow Paraparatrechina worker phenotype range (typically workers of these species vary by only slight difference in setation and color tones of yellow and brownish-yellow) and therefore identification of the species can be difficult. It is morphological similar to three Aftrotropical species: Paraparatrechina gnoma , Paraparatrechina oreias , and Paraparatrechina subtilis . In practice, a relatively straight forward, non-morphological way, to separate Paraparatrechina illusio is it is only known from the Seychelles, while the remaining three species are from West and Central Africa. Morphologically, it differs from Paraparatrechina gnoma in being slightly larger overall and in coloration ( Paraparatrechina gnoma is brownish-yellow with lighter yellow patches). From Paraparatrechina oreias the main difference also lies in color. The gaster of Paraparatrechina oreias is brownish-yellow, contrasting slightly with the remainder of the body. The metanotal area of Paraparatrechina oreias is also more distinctly defined than is seen in Paraparatrechina illusio . From Paraparatrechina subtilis , the difference is in the pubescence. Whereas the pubescence on the head of Paraparatrechina subtilis is decumbent throughout, on Paraparatrechina illusio it is only decumbent lateroanteriorly around eyes. Additionally the gastral pubescence is different between the two: in Paraparatrechina subtilis it is longer and slightly decumbent, contrasting with the shorter, tightly appressed pubescence observed in Paraparatrechina illusio .