Sphaeridia Linnaniemi, 1912

Medeiros, Gleyce da Silva, Silva, Clecio Danilo Dias da, Franca, Josemaria Silva de, Godeiro, Nerivania Nunes & Bellini, Bruno Cavalcante, 2023, Two new species of Sminthurididae (Hexapoda, Collembola, Symphypleona) from Brazil with notes on Denisiella Folsom & Mills and Sphaeridia Linnaniemi, ZooKeys 1173, pp. 1-41 : 1

Genus Sphaeridia Linnaniemi, 1912

Diagnosis of the genus.

Antennal sexual dimorphism weak, Ant II and III in males only with b1 and c3 modified elements, respectively, antennal bothriotricha absent, long sensilla present in both segments. Ant IV undivided in both sexes. Head chaetae usually uniform, sometimes short, and thick. Eyes 5+5 to 8+8, ommatidia C and D small if present. Th III in males without vesicles. Large abdomen bothriotricha ABC misaligned. Posterior large abdomen with long chaetae. Ventral tube corpus of males usually modified, with 1+1 extra vesicles (other than the sacs) and/or several complex processes; corpus of females mostly with 1+1 extra vesicles; ventral tube with 0+0 or 1+1 chaetae in both sexes. Tibiotarsi I-II without any clear modifications in both sexes; tibiotarsus III of males usually with modified chaetae IIpe, IIIpi and IVpi; tibiotarsus III of females usually with modified chaetae IIIpi and IVpi; distal tibiotarsal organ of leg III absent. Ungues I and II usually more slender than the unguis III. Unguiculi I-II with a narrow lamella and a long distal filament, unguiculus III with or without the distal filament, if present, short. Dens dorsally with or without the basal appendage, chaetae E1 and J1-3 usually spiniform. Dens ventral chaetotaxy following the formula 2,3,2 … 1 (rarely 2,2 … 1 or 2,2,1 … 1) from the apex to the basis. Mucro narrow, inner edge serrated, outer smooth, without the chaeta (adapted and revised from Krausbauer 1898; Linnaniemi 1912; Salmon 1951; Massoud and Delamare-Deboutteville 1964; Murphy 1965; Richards 1968; Massoud and Betsch 1972; Betsch 1980; Arlé 1984; Mari Mutt 1987; Bretfeld and Gauer 1994; Bretfeld 1995, 1997, 1999, 2002; Bretfeld and Trinklein 2000; Bretfeld and Schulz 2012).

Type species.

Sminthurus pumilis Krausbauer, 1898.

Distribution.

Worldwide ( Bretfeld 1999).

Remarks.

Here we surveyed and compared the 46 Neotropical species of Sphaeridia (Table 1 ). Many species of the genus are described based mainly in the male ventral tube morphology and leg III modified chaetae, characteristics which are variable and useful for the separation of species ( Bretfeld and Gauer 1994; Bretfeld 1997, 1999, 2002; Bretfeld and Trinklein 2000; Bretfeld and Schulz 2012). However, such descriptions lack further data, especially on the antennal, large and small abdomen morphology/chaetotaxy, features which may be useful alone or at least are complementary to distinguish the species.

According to Bretfeld and Gauer (1994), Sphaeridia holds four groups of species separated by the male ventral tube morphology (Table 1 , Figs 1 - 5 ). The Sphaeridia pumilis group is characterized by species usually with only 1+1 small posterior vesicles or rarely lacking such structures, without further modifications on the ventral tube (Figs 1A , 2E , 3G , 4C , 4E-F , 5E ); the brevipila group is characterized by taxa with a posterior median process (usually with extra processes as well) on the ventral tube (Figs 1B-L , 2C, D , 2F , 2I-L , 3A, B , 3D-F , 3H-J , 4D , 4K , 5A-D , 5F-I ); the Sphaeridia irmleri group is represented by species with posterior and lateral complex symmetrical processes on the ventral tube (Figs 2G, H , 3C , 4A, B ); and the Sphaeridia spira group is characterized by taxa with complicated asymmetrical structures on the ventral tube (Fig. 4G-J ), combined with extra modified chaetae on male tibiotarsus III.

In our survey of the Neotropical Sphaeridia we noticed that at least eight species do not have enough characters to clearly differ them from other congeners or to keep them in the genus, and so we are considering them as species inquerendae. These taxa are S. aspinosa Bretfeld & Trinklein, 2000, S. biniserrata (Salmon, 1951) sensu Massoud & Delamare-Deboutteville (1964), S. delamarei Bretfeld, 1997, S. duckei Bretfeld, 2002, S. gladiolifer Delamare-Deboutteville & Massoud, 1964, S. martii Bretfeld & Gauer, 1994, S. multispina Bretfeld & Schulz, 2012 and S. serrata (Folsom & Mills, 1938). Sphaeridia aspinosa and S. multispina males do not present the typical clasper organ with modified Ant II and III chaetae seen in all other Sminthurididae . Bretfeld and Trinklein (2000: 190) and Bretfeld and Schulz (2012: 515) suggested these specimens could be anomalous, but they had few specimens of both species to confirm such condition as abnormal. Also Bretfeld and Trinklein (2000: 190) suggested the absence of the clasper could imply that S. aspinosa , and consequently S. multispina , may belong to an undescribed different basal genus of the family, which makes these species not comparable with the other taxa of Sphaeridia and their descriptions in need for a revision. Sphaeridia duckei was described based on a single female with different features from those seen in all other Sminthurididae , like capitate tenent hairs in all pairs of legs and trunk bothriotricha ABC aligned, which may indicate this specimen may be a subadult of another family, like Bourletiellidae . It is worth noting that Bretfeld (1999:52) suggested that the records of the type species of Sphaeridia must be confirmed with males, because the females do not show differences in many species, supporting our view of S. duckei . On the other hand, S. biniserrata , S. delamarei , S. gladiolifer and S. serrata likely belong to Sphaeridia , but their descriptions lack sufficient information about the antennae, legs and/or ventral tube to clearly separated them from other taxa, which makes comparisons with other species arbitrary (see Table 1 ). Finally, S. martii does not fit in Sphaeridia since the morphology of its male antennae is more complex compared to other taxa, presenting modified chaetae b1-b 3 on Ant II and c1-c3 on Ant III. Even with this observation, its placement among the Sminthurididae is still unclear. So we believe all these species need redescriptions and a revision of their placement within the family.

Figures

Figure 1. Morphology of the ventral tube of males of Sphaeridia spp. A apex in S. aserrata Mari-Mutt, 1987 B posterior side in S. aspinosa Bretfeld & Trinklein, 2000 C posterior side in S. biclava Bretfeld & Trinklein, 2000 D posterior side in S. bivirgata Bretfeld, 2002 E posterior side in S. boettgeri Bretfeld & Gauer, 1994 F Detailed view of the anterior mandible-like processes of S. boettgeri G anterior side (apex) in S. boettgeri H apex in S. cardosi Arle, 1984 I apex in S. cardosi (specimens from a different locality) J apex in S. carioca Arle, 1984 K posterior side in S. catapulta L anterior side in S. cerastes Bretfeld & Gauer, 1994. Figures adapted from species' original descriptions.

Figure 2. Morphology of the ventral tube of males of Sphaeridia spp. (cont.) A posterior side in S. cerastes B apex in S. cerastes C anterior side in S. chisacae Bretfeld & Gauer, 1994 D posterior side in S. chisacae E posterior side in S. coronata Bretfeld & Gauer, 1994 F posterior side in S. decemdigitata Bretfeld & Schulz, 2012 G apex in S. fibulifera Bretfeld & Gauer, 1994 H anterior side in S. fibulifera I apex in S. fluminensis Arle, 1984 J apex in S. fluminensis (another view) K apex in S. franklinae Bretfeld & Gauer, 1994 L posterior side in S. franklinae. Figures adapted from species' original descriptions.

Figure 3. Morphology of the ventral tube of males of Sphaeridia spp. (cont.) A apex in S. heloisae Arle, 1984 B apex in S. heloisae (another specimen) C posterior side in S. irmleri Bretfeld & Gauer, 1994 D posterior side in S. lobata Bretfeld & Gauer, 1994 E posterior side in S. mandibulata Bretfeld & Gauer, 1994 F anterior side in S. mandibulata G posterior side in S. multispina Bretfeld & Schulz, 2012 H posterior side in S. panguanae Bretfeld & Schulz, 2012 I posterior side in S. paroara Arle, 1984 J apex in S. paroara. Figures adapted from species' original descriptions.

Figure 4. Morphology of the ventral tube of males of Sphaeridia spp. (cont.) A posterior side in S. peruensis Bretfeld & Schulz, 2012 B apex in S. peruensis C posterior side in S. pilleata Bretfeld & Gauer, 1994 D posterior side in S. schalleri Massoud & Delamare-Deboutteville, 1964 E posterior side in S. squamifera Bretfeld & Gauer, 1994 F anterior side in S. squamifera G apex in S. spira Bretfeld & Gauer, 1994 H apex in S. spira, detailed view of the two asymmetrical lobes I posterior side in S. sturmi Bretfeld & Gauer, 1994 J apex in S. sturmi K posterior side in S. torifera Bretfeld & Schulz, 2012. Figures adapted from species' original descriptions, with the exception of S. schalleri which was adapted from Bretfeld (1997).

Figure 5. Morphology of the ventral tube of males of Sphaeridia spp. (cont.) A apex in S. torifera B posterior side in S. tropica Bretfeld & Schulz, 2012 C detail of the apex of the posterior side in S. tropica D detail of the apical lobes in S. tropica E posterior side in S. tschirnhausi Bretfeld & Schulz, 2012 F posterior side in S. vampyra Bretfeld & Schulz, 2012 G lateral side in S. vampyra, detail of the posterior median plane H lateral side in S. vampyra, detail of the posterior lateral plane I posterior side in S. winteri Massoud & Delamare-Deboutteville, 1964. Figures adapted from species' original descriptions, with the exception of S. winteri which was adapted from Bretfeld (1997).

Figure 11. Sphaeridia piauiensis sp. nov. male abdominal appendages A ventral tube (lateral view) B manubrial chaetotaxy (lateral view) C ventral dens chaetotaxy D dorsal dens chaetotaxy and mucro.