Pseudosinella argentea Folsom, 1902

Soto-Adames, Felipe N., 2010, Two new species and descriptive notes for five Pseudosinella species (Hexapoda: Collembola: Entomobryidae) from West Virginian (USA) Caves, Zootaxa 2331, pp. 1-34 : 13-17

Pseudosinella argentea Folsom, 1902

Figs 35–54 , Table 5

Material Examined. PENDLETON Co., Quarry Cave, 20 May 2006, 2 on one slide and 3 in alcohol; Cedar Cave, 15 May 2006, 1 on slide; Hoffman Pit, 20 May 2006, 1 on slide, 3 in alcohol; MONOGALIA Co., Maiden Run #1 Cave, 12 June 2006, 1 on slide.

Descriptive notes. Length to 2.5mm; color in alcohol white, without trace of pigment, or just a wash of light blue pigment near base of antennae. Ant. 4 subapical sense organ clavate, or appearing capitate in some angles ( Fig. 35 ). Ant. 3 sense organ formed by two enlarged sensilla ( Fig. 36 ). Dorsal head chaetotaxy ( Fig. 37 ) with 7–9 macrosetae along base of antennae; A0, A2, and A3 macrosetae; Pa5 a microseta; A1 and M0 ciliate microsetae, all other dorsal microsetae smooth; seta S0 anterior to S3; M1/S1 near M2. Eyes absent. Prelabral setae ciliate, all labral setae smooth. Labral intrusion and papillae as in Fig. 39 . Pleural fold setae ciliate; peristomal setae pss0 normal ciliate, pss1–2 ciliate and bothriotricha-like. Ungulum of maxilla with 4 teeth. Lateral process of labial papilla E slightly curved dorsally and barely reaching papillar tip. Proximal seta of labial palp with seta Y subequal to somewhat longer than seta Z. Ventral head chaetotaxy as Fig. 38 : labial chaetotaxy M1M2rEL1L2A1–5, microseta r smooth and thin walled; post-labial chaetotaxy includes 4+4 ciliate setae along ventral groove, and columns C, E, L and O with 2, 2, 3 and 2 setae respectively; L2 and O1 modified into short, ciliate and sharply acuminate microsetae. Inner macrochaetotaxy of the body 00/ 0100+2.

argentea sensu Christiansen & Bellinger (1998) .

1 Original description (Christiansen & Bellinger 1986) mentions 6–7 setae but Figure 46 shows 9.

Abd. 1 with setae in linear arrangement, a6 present. Chaetotaxy of Abd. 2 as in Fig. 42 ; a2, a6 and all supplementary setae of bothriotrichal complexes fan-shaped; a2p and a3 more strongly ciliate than others; a3 external and reaching tip of as; as reaches the socket of m 3 in some individuals, but not in others; m3e not reaching socket of m3; supplementary seta m 4i ciliate, to weakly fan-shaped (the presence of microsetae m 4i is often difficult to ascertain because the surrounding fan-shape setae tend to obscure m 4i ’s socket); m5 a normal macroseta; p5p a short, ciliate mesoseta. The male from Quarry Cave has supernumerary setae associated with seta p5p on Abd. 2 and m 4i appears to be displaced anteriorly towards a5, but only on one side of the body (arrows on Fig. 44 ). Abd. 3 ( Fig. 45 ) with a2, a6, am6 and all supplementary setae associated with bothriotrichal complexes fan-shaped, all other setae weakly ciliate, but appearing smooth at low magnification; a3 not reaching as; as about 0.5x the length of m3 and reaching base of m3; d2 present; a7, m7 and p7 normal microsetae, m7a a long and slender acuminate macroseta, a7 inserted anterior and close to am6, m7 posterior to p6. Abd. 4 bothriotrichal complex as in Fig. 46 : all supplementary setae anterior to T2, including seta s, fan-shaped; C1p and T3 weakly ciliate (appearing smooth at low magnifications); tip of T3 reaching base of D1p; D1p posterior to T3 and reaching the base of Pe; Pe and Pi fan-shaped; the male from Quarry Cave carries an asymmetric supplementary seta between Pe and T5 (arrow in Fig. 46 ). General chaetotaxy of Abd. 4 ( Fig. 47 ) with macrosetae B5, B6, T6, T7, D2 D3, E2, E3, F1, F3; E1 and F2, microsetae; macroseta B5 on line drawn between A5 and C2; F2 closer to E3 than E2; microseta posterior to E3 absent. Abd. 4 usually with 1+1 posterior setae, but varying among some caves: specimens from Quarry Cave, Hoffman’s Pit and Cedar Cave, and Maiden Cave have 2+2, 3+3 and 4+4 posterior setae, respectively. Trochanteral organ with 14–15 setae. Metathoracic femora with two outstanding acuminate macrosetae inserted near basal third of the segment ( Fig. 48 ). Tenet hair as long as unguiculus, acuminate or truncate, varying according to locality. The two individuals from Quarry Cave, and the individual from Hoffman’s Pit have acuminate tenet hairs on the pro- and mesothoracic legs ( Fig. 49 ), but truncate on metathoracic legs ( Fig. 52 ); the individual from Cedar Cave has all tenent hairs truncate, and the individual from Maiden Run Cave has all tenent hairs acuminate. Unguiculus lanceolate with indistinct serrations on posterior lamella, all other lamellae smooth. Unguis with three inner teeth ( Figs. 49, 52 ): basal pair unequal in size ( Fig. 51 ), the difference in size between teeth being more prominent on metathoracic legs; unpaired tooth prominent and closer to ungual tip than base. Outer ungual teeth ( Fig. 50 ) short, closer to ungual base on third pair than on first two pairs of legs (cf. Figs. 49, 52 ). Collophore with 8+8 disto-lateral setae, four ciliate and four smooth; anterior face with variable number of setae, but generally arranged as in Fig. 54 ; posterior face ( Fig. 53 ) with 5+5 proximal and nine distal setae. Manubrial plate ( Fig. 43 ) with six outer and two inner setae separated by two pseudopores. Mucro ( Fig. 41 ) normal, with teeth subequal; mucronal spine with basal swelling.

Remarks. These specimens belong to the P. argentea complex, although specific determination remains ambiguous and is based on the preponderance of similarity with that apparently very variable species. The material from West Virginia keys out to P. flatua Christiansen & Bellinger, 1996 in Christiansen & Bellinger (1998) by the presence of a ciliate seta a2p on Abd. 2, but differs from that species in many chaetotacic characters of the labrum, labium, postlabium and ventral tube ( Table 5 ). The variation in tenent hair shape and number of posterior setae on Abd. 4 suggest that these samples may include more than one species, but as with other cave forms, the limited material available makes a final determination difficult.

Figures

FIGURES 35 – 44. Pseudosinella argentea: 35, Subapical sensilla of forth antennal segment; 36, Sense organ of third antennal segment; 37, Dorsal head chaetotaxy; 38, Labial and postlabial chaetotaxy; 39, Anterior margin of labrum; 40, Sublobular plate of outer maxillary lobe; 41, Mucro; 42, Chaetotaxy of second abdominal segment; 43, Distribution of setae on distal manubrial plate, left side; 44, Atypical chaetotaxy of second abdominal segment in another individual.

FIGURES 45 – 54. Pseudosinella argentea: 45, Chaetotaxy of third abdominal segment; 46, Bothriotrichal complex of fourth abdominal segment; 47, Complete chaetotaxy of fourth abdominal segment; 48, Metatibiotarsus showing enlarged setae; 49, Prothoracic claw complex; 50, Anterior view of outer ungual teeth on metathoracic leg; 51, Posterior view of inner ungual teeth of prothoracic leg; 52, Metathoracic claw complex; 53, Posterior chaetotaxy of collophore; 54, Anterior chaetotaxy of collophore, left side.

Tables

TABLE 5. Comparison between Pseudosinella from West Virginia here identified as argentea, and flatua, granda and

Species	Head macroseta A0	Prelabra l setae	Sense organ Ant. 3	Labial setae m1 & m2	Labial seta r	Head ventral groove setae	Abd. 2 seta a3	Abd. 2 seta a2p	Ventral Tube anterior chaetotaxy	Ventral Tube posterior chaetotaxy (total/distal margin)	Ventral Tube vesicle base chaetotaxy
West Virginia ‘ argentea ’	1	ciliate	swollen	M1≈M2	smooth, thin walled blunt microseta	4 ciliate	ciliate	ciliate & ≈ a2	9	19/9	7–8; 4 ciliate
argentea	1	?	swollen	M1≈M2 or M1≈M2	smooth or truncate microseta or absent	4 ciliate	?	smooth	?	?	?
granda	2	ciliate	swollen	M1≈M2	Absent or conic reduced	4 ciliate	smooth	ciliate &> a2	9 1	13/7	8–9; 4–5 ciliate
flatua	1	smooth	slightly swollen	m1<M2	smooth acuminate microseta	3 smooth 1 ciliate	smooth	ciliate &> a2	11–13	14/?	11–13