Parajapyx silvestrii Montejo-Cruz, García-Gómez & Palacios-Vargas, 2021

Montejo-Cruz, Maira, García-Gómez, Arturo & Palacios-Vargas, José G., 2021, Four new species of Parajapyx (Diplura: Parajapygidae) from Mexico with redescription of Parajapyx isabellae aztecus Silvestri, Zootaxa 4948 (2), pp. 221-244 : 222-223

Parajapyx silvestrii Montejo-Cruz, García-Gómez & Palacios-Vargas , sp. nov.

Figs. 1–13 ; Tables 1–2.

Type specimens. Holotype (male) on slide: Mexico, Quintana Roo, Cozumel Island, Colombia Lake, 24/vi/ 2010, litter and sand mangrove, A. García Gómez, coll. Deposited at “Colección de ácaros y colémbolos”, Facultad de Ciencias , UNAM . Paratypes (three females) on slides: Mexico, Quintana Roo, Cozumel Island, San Gervacio, 24/vi/ 2010, litter of tropical dry forest, A. García Gómez, coll. Deposited at “Colección de ácaros y colémbolos”, Facultad de Ciencias , UNAM .

Etymology. This species is named after the Italian entomologist, Filippo Silvestri, who was one of the first researchers to study the diplurans from Mexico and the world.

Description. Holotype (male): body length 1.7 mm. Paratypes (three females): body length range (n=3) 1.62‒ 1.8 mm. Cuticle ornamentation in the shape of hexagon cells.

Head vertex ( Fig. 1 ) with 9+9 normal setae and 2+2 normal setae close to the antennae; front with 1+1 macrosetae and 4+4 normal setae; labrum with 1+1 normal setae and 6+6 microsetae. On head venter ( Fig. 2 ) inner lobe with 1+1 normal setae, external lobe with 13+13 normal setae. In place of labial palpus 1+1 macrosetae, 3+3 normal setae, of which two are smaller; admentum with 2+2 macrosetae and 10+10 normal setae; plica orales with 6+6 normal setae, submentum with 2+2 normal setae.

Mandible ( Fig. 3 ) with five teeth and four denticles, maxilla with first lamella slender and slightly larger than half of the second, other lamellae pectinate and similar each other; maxillary palp with 9 normal setae and one apical microsensillum.

Antennae ( Fig. 4 ) with 18 segments, bacilliform setae number in antennal segments as follows: I‒IV, 0; V, 1; VI, 1‒2; VII, 3‒4; VIII‒XI, 4‒5; XII‒XV, 4‒6; XVI, 8; XVII, 8 or 10; XVIII, more than 10 and four placoid sensilla.

Thoracic chaetotaxy is shown in Table 1 ( Fig. 1 ).

Without one macrosetae ma and one macrosetae mp in the mesoscutum and metascutum.

Length of Leg III ( Fig. 5 ) 0.2mm, with smooth setae; coxa with 3 normal setae and 2 microsetae; trochanter with 3 normal setae; femur with 10 normal setae and 3 microsetae; tibia with 8 normal setae; tarsus with 10 normal setae; claws symmetrical.

Abdominal chaetotaxy is shown in Table 2 ( Figs.6, 8, 9 ).

Some macroseta are reduced or small than usual in scutum of the segment I and tergite X.

Tergite IX (length= 0.12 mm) ( Figs. 8, 9 ) similar in length to tergite VIII. Tergite X with reduced macrosetae 4 ( Fig. 8 ). On sternite I ( Fig. 7 ) prescutum with 3+3 normal setae and 3+3 microsetae; scutum with 10+10 normal setae and 4+4 microsetae. Typical styles of the genus. Subcoxal organ ( Fig. 10 ) with 5 accompanying setae, 12 glandular setae and 2 sensorial setae. On sternite II ( Fig. 7 ) to VII prescutum with 3+3 normal setae and 4+4 microsetae; scutum 11+1+11 normal setae and 4+4 microsetae. Eversible vesicles present on sternites II and III. Female genital papilla valves ( Fig. 11 ) each with 5 normal setae, one internal microsensillum and one external microsensillum. Male genital papilla ( Fig.11 ) with 6+6 normal setae.

Each cercus ( Figs.12, 13 ) with five internal teeth; D5 and D4 small, inconspicuous, D3 and D1 larger, and D3 and D2 present bumps. Cerci without “e” setae, but with two setae, M2’ and a’, close to seta M2, these setae had not been mentioned previously by other authors. Ventrally, M3 absent. Each cercus with five pores dorsally, each one inside a cuticular depression.

Phyletic affinities. Parajapyx silvestrii sp. nov. differs from all other Parajapyx species by the presence of five cuticular pores in depressions in each cercus and absence of one ma and mp macrosetae on the mesoscutum and metascutum, mp macroseta on abdominal tergite I and ma macrosetae on abdominal tergites II to VII. Only Parajapyx adisi Pagés, 2000 from Brasil and Parajapyx remyi Páges, 1953 from Sahara at northwest of Africa lack some macrosetae, but these species presents all macrosetae in mesoscutum and metascutum and the macrosetae absent on abdominal tergite I are not same (the absence macrosetae are ma and la).

Figures

FIGURES 1–5. Parajapyx silvestrii sp. nov.; 1. Dorsal view of head and thoracic nota (scale 60 µm): 2. Ventral head (Scale 60 µm). 3. Maxilla, mandible and labrum (scale 20 µm). 4. Antennal segments IV, V and XVIII (only the dorsal 7 bacilliform sensilla and 2 placoid sensilla shown for XVIII) (scale 20 µm). 5. Leg III (scale 50 µm).

FIGURES 6–9. Parajapyx silvestrii sp. nov.; 6. Abdominals tergite I and II (scale 90 µm). 7. Abdominals sternites I and II (scale 90 µm). 8. Tergites VIII‒X, dorsal view (scale 70 µm): 9. Tergites VIII‒IX, ventral view (scale 70 µm).

FIGURES 10–13. Parajapyx silvestrii sp. nov.; 10. Subcoxal organ (scale 20 µm). 11. Female genital papilla (scale 20 µm). Male genital papilla (scale 20 µm). 12. Cerci dorsal view (scale 50 µm): 13. Cerci ventral view (scale 50 µm).