Psammophorura neocaledonica Thibaud & Weiner, 1997

Bu, Yun, Potapov, Mikhail B. & Gao, Yan, 2013, A new species and new records of Pachytullbergiidae and Tullbergiidae (Collembola: Onychiuroidea) from littoral of China, with notes on the variations of postantennal organ, Zootaxa 3669 (2), pp. 139-146 : 143-145

Psammophorura neocaledonica Thibaud & Weiner, 1997

Figs 10–16

Material examined. Two females and 7 males (slides Nos. 5, 6, 7), East China, Zhejiang Province, Zhoushan city, Shengsi Island, 30°40' N 122°15'E, beach with grass dunes, flotation of sand samples, 5.iv.2009, M. B. Potapov, Y. X. Luan, and Y. Bu leg; 1 female and 1male (No. 47), 2 females (No. 42), East China, Zhejiang Province, Zhoushan city, eastern part of Zhujiajian island, 29°50' N 122°50'E, sandy beach, supralittoral thin sand, with roots and dirt, 12.iv.2011, M. B. Potapov and C. W. Huang leg.

6 female (Nos. 81, 85-1, 88, 91, 98-1, 98-2,) and 3 males (Nos. 85-2, 86-1, 86-2), East China, Shandong Province, Yantai City, 37°27' N 121°30'E, middle beach with grass dunes, flotation of sand samples, 22.iv.2011, M. B. Potapov, Y. X. Luan and C. W. Huang leg. 2 females (Nos. 1-1, 1-2), East China, Shandong Province, Yantai City, Golden Beach, flotation of sand samples, supralittoral, thin sand under the roots of ruderal plants, 37°34' N 121°13'E, 20.iv.2011, M. B. Potapov, Y. X. Luan and C. W. Huang leg; 8 females (Nos. 1-1, 1-2, 2), 1 male (Nos. 4), East China, Zhejiang Province, Zhoushan city, Shengsi Island, 30°40' N 122°15'E, beach with grass dunes, flotation of sand samples, 22.x.2011, Y. Gao and Y. Bu leg. 1 female and 1 juvenile (Nos. 1, 2), East China, Fujian Province, Fuzhou city, Changle county, 25°53' N 119°37'E, sandy beach close to Changle airport, dunes with roots and grass, 5.v.2012, Y. X. Luan, Y. Gao and Y. Bu leg.

Description of the specimens from China. Adult body 500–630 μm long and 100–110 μm wide (n=20). Setae hardly differentiated into micro- and macrosetae ( Figs 10, 11 ). Labium with 5 papilla, 6 apical guard setae, 6 proximal setae, 4 basomedian setae, and 5 basolateral setae. Number (40–65) and arrangement of vesicles in postantennal organ variable ( Fig. 12 ).

Lateral sensory chaetae s on meso- and metanotum17–18 μm long ( Fig. 11 ). Pseudocelli formula: 11/011/ 11111, 8–10 μm in diameter, on thorax between setae p2 and p3, and close to p3, on abdomen posterior to seta p3 ( Figs 11, 12 ). Type of pseudocelli variable among different segments, head, thorax and abdominal tergite V with type I, and Abd. I–IV with type I or type III.

Antenna (65–70 μm) shorter than head (75–90 μm). Antennal segment IV ( Fig. 13 ) with four slightly thickened sensilla a–e, without basal heel. Small microsensillum and subapical organite and one apical vesicles present. Antennal organ III ( Fig. 13 ) consists of two thick sensory clubs bent toward each other and two two small sensory rods concealed behind two high papilla, protected by four guard setae.

Legs short, without clavate tibiotarsal hairs. Coxa with 3, 7, 7 setae, trochanter with 6, 6, 5 setae, femur with 9, 9, 9 setae and tibiotarsus with 11, 11, 11 setae on leg I, II and III, respectively. One seta on femur of all legs much smaller than remaining ones. Anal lobes with seta l 2'. Claw 8–10 μm long. Anal spines 5–7 μm long.

Abdominal tergite V with sensory chaeta p3 slightly differentiated or, more rarely, flame-like ( Fig. 11 ). Seta p2 located in posterior position, at level of seta p3 ( Fig. 11 ). Number of ventral setae on Abd. II, III and IV variable, with 19–20, 18–20, and 22–26 setae respectively ( Figs 15, 16 ). Ventral tube with 4 + 4 apical setae and 2 + 2 basal ones ( Fig. 15 ). Male genital plate with 10-13 setae ( Fig. 14 ).

Distribution. New Caledonia, Vanuatu, Vietnam, Madagascar. It is probably distributed widely in China (Shandong, Zhejiang, Fujian).

Remarks. Psammophorura neocaledonica is a new record for Chinese fauna. After Thibaud & Weiner (1997) and Thibaud (2008), it is distinguished from P. gedanic a Thibaud & Weiner 1994, by higher number of vesicles in PAO (50 vs. 40), less differentiated sensory chaeta p3 and presence of a2 on Abd. V. Number of vesicles in PAO is considered to be of high taxonomical value in taxonomy of Tullbergiidae , for instance in genera Multivesicula Rusek, 1982 , Mesaphorura Börner, 1901 , and Metaphorura Bagnall, 1936 . After our observations on Chinese specimens of P. neocaledonica , we found high variability of number (40 to 65) and arrangement of vesicles ( Fig. 12 ) in PAO. Specimens with asymmetrical PAO also occurs.

The presence of two types of pseudocelli was described as an important character of genus Psammophorura (Thibaud & Weiner 1994) . However, Fjellberg (1998) recorded some specimens of P. gedanica from Norwegia with pseudocelli of type I only. In Chinese specimens, the type of pseudocelli is also variable, most of individuals of P. neocaledonica have pseudocelli of type I only ( Figs10–11 ), pseudocelli of type III was found on abdominal tergites I–IV in few individuals.

We found that the shape of sensory chaetae p3 on Abd. V is also variable ( Fig. 11 ), from slightly differentiated to flame-like (vs. slightly differentiated in type population). As an additional differential character is the posterior position of p2 seta on Abd. V.: in P. gedanica p2 is in mid-tergal position like in most other species of the family (vs. posterior-tergal position in P. neocaledonica ).

The differences we found between Chinese and New Caledonian specimens are the number of setae on trochanters (6, 6, 5 vs. 5, 5, 4) and tunica of claw (larger in Chinese specimens).

Figures

FIGURES 10 – 12. Psammophorura neocaledonica: 10, dorsal chaetotaxy of head and thorax; 11, dorsal chaetotaxy of abdomen; 12, variability of PAO; s –– sensory chaeta, ms –– microsensillum.

FIGURES 13 – 16. Psammophorura neocaledonica: 13, antennal segments III and IV, dorsal view; 14, male genital plate; 15, ventral chaetotaxy of Abd. I – III; 16, ventral chaetotaxy of Abd. IV – VI.