First record of growth rings for 11 native subtropical anuran species of South America

Abstract

Abstract: Skeletochronology is the most accurate method to estimate a population age structure. The methodology is based on the analysis of secondary bone tissue in order to count growth rings. This study aimed to provide initial data, allowing researchers to further work out in the age of individuals and populations, sampling evidence of the presence of growth rings in 11 native species (representing nine families) of a subtropical region of southern Brazil. Four bone samples of each specimen were used to perform the skeletochronological analysis: the penultimate phalanges of the 3rd and 4th fingers, the humerus, and the femur. The presence of growth rings was confirmed in the periosteal layer of the bones of all analyzed species. In comparison with phalanges, growth rings of humeri and femora are more irregular and less distinguishable. This is the first record of growth rings to the native species herein analised. The skeletochronology was proved to be an effective tool in determining the age of anuran amphibians from a subtropical region, since this environment presents well defined climatic seasonality.

Key words
Bone chronology; frogs; lines of arrested growth; southern Brazil

INTRODUCTION

The study of amphibians’ population age structure is crucial to understanding population dynamics and species natural history, since it provides information regarding growth rate, sexual maturity, longevity, and reproductive lifespan (Li et al. 2010). The analysis of bone tissue to estimate age (known as skeletochronology) has been used in both fossil (Botha and Chinsamy 2000, Sander 2000, Tütken et al. 2004, Botha-Brink et al. 2018) and extant tetrapods, such as ‘reptiles’ (Avens et al. 2009, Goshe et al. 2010), birds (Ricqlès et al. 2003), and amphibians (Socha and Ogielska 2010, Cajade et al. 2013, Bionda et al. 2015, Sun et al. 2016, Kumbar and Lad 2017, Tessa et al. 2017). Skeletochronology is based on the presence of growth rings (lines of arrested growth — LAGs) in transverse sections of the bones, in which broad lines represent the growth period and narrow lines represent a growth pause. Thus, each narrow line characterizes one growth year, allowing the estimation of the age of individuals (Castanet and Smirina 1990).

The formation of annual growth marks in anurans from temperate zones occurs due to seasonal climatic variation, since growth is delayed along the winter (Castanet et al. 2003). According to Castanet et al. (1993), annual formation of LAGs has a genetic basis and under natural conditions their formation is synchronized with the climatic seasonality. It is noteworthy that age estimation by LAGs counting is effective only if the species’ growth pattern is annual (Gibbons and McCarthy 1983). However, although some studies point that anurans from environments with low seasonal climatic variation usually present an irregular pattern of LAGs formation (Kusrini and Alford 2006), other studies indicate that species from tropical regions may also have evident LAGs (Rebouças et al. 2018).

Southern Brazil has a subtropical climate and resembles temperate regions concerning seasonal temperature variation (Overbeck et al. 2007). The heterogeneous environment in southern Brazil hosts an anuran fauna distributed in nine recognized families: Alsodidae, Bufonidae, Centronelidae, Hylidae, Hylodidae, Leptodactylidae, Microhylidae, Odontophrynidae, Phyllomedusidae (Santos et al. 2014). However, studies of subtropical herpetofauna are mainly focused on investigating the communities’ structure (Eterovick et al. 2005), and describing the species distribution patterns (Rosset et al. 2006). Therefore, studies involving skeletochronology of native species from South American subtropical regions are scarce (Echeverria and Filipello 1990, Marangoni et al. 2009, Iturra-Cid et al. 2010, Cajade et al. 2013, Caldart et al. 2019). Thus, we investigated the presence of LAGs in anurans representing all families (11 native species) of southern Brazil.

MATERIALS AND METHODS

Skeletochronology was applied in species of wide distribution in southern Brazil (Paraná, Santa Catarina, and Rio Grande do Sul states). According to Koppen’s climate classification, the region’s climate is considered humid subtropical (Cfa-Cfb), with well-defined temperature seasonality (Alvares et al. 2013). All sampled species have seasonal activity pattern linked to the warm season (see Sá and Gerhau 1983, Kwet and Miranda 2001, Kaefer et al. 2007, Both et al. 2008, Narvaes and Rodrigues 2009, Machado et al. 2014, Caldart et al. 2016): Alsodidae — Limnomedusa macroglossa (Duméril and Bibron 1841); Centronelidae — Vitreorana uranoscopa (Müller 1924); Bufonidae — Rhinella fernandezae (Gallardo 1957) and Melanophryniscus atroluteus (Miranda-Ribeiro 1920); Hylidae — Boana pulchella (Duméril and Bibron 1841) Hylodidae — Crossodactylus schmidti (Gallardo 1961); Leptodactylidae — Leptodactylus fuscus (Schneider 1799) and Physalaemus cuvieri (Fitzinger 1826); Michroylidae — Elachistocleis bicolor (Guérin-Méneville 1838); Odontophrynidae — Odontophrynus americanus (Duméril and Bibron 1841); Phyllomedusidae —Phyllomedusa iheringii (Boulenger 1885). All specimens used were already deceased and deposited in the herpetological collection of the Santa Maria Federal University (ZUFSM — Appendix).

Three specimens of each species were examined. The following measurements were made for each specimen: body mass (BM), using a balance (0.01-g precision) and snout-vent length (SVL), using a digital caliper to the nearest 0.01 mm. The specimens were dissected to extract bone samples from penultimate phalanges of the 3^rd and 4^th fingers of the foot, and long bones (humerus and femur). As a standardization procedure, all bone samples were collected from the limbs on the right side of the specimens.

After extraction, the bone samples were dehydrated on an increasingly series of alcohol (70–100%) for one hour for each step. Then, they were decalcified in 10% ethylenediaminetetraacetic acid (EDTA) for one week. Thereafter, the bones were processed in historesin, transversely sectioned in a Leica RM 2245 rotary microtome, and stained using toluidine blue for ten minutes (Caputo et al. 2010). After stained, the samples were dried in kiln for one day. For each specimen, four sections from the middle region of the bone diaphysis were taken. Slices were independently analyzed using a Zeiss Axio Scope A1 microscope with an Axiocam MRc 5 digital camera by at least two different authors. To identify the occurrence of bone resorption in long bones, the LAGs counting was comparatively analyzed considering phalanges as references. The bone resorption was also determined based on the absence of remaining cartilage tissue from the larval stage (line of metamorphosis) (Rozenblut and Ogielska 2005).

RESULTS, DISCUSSION AND CONCLUSIONS

Transverse sections of phalanges and long bones of all species exhibited LAGs. Although the rings were not uniformly clear in all bones, LAGs were observed in the periosteal layer of the bones of all analyzed species. Phalanges and long bones often had the same number of LAGs. However, the phalanges allowed a better identification of LAGs than long bones and considering long bones, identification of LAGs was better in the femur than in the humerus. Likewise, regarding the phalanges, the identification of LAGs was better in the phalanges of the 4^th finger than in phalanges of the 3^rd finger.

The number of LAGs identified in the studied species was (see Table I): M. atroluteus (2-3; Fig. 1b), C. schmidti (1-3; Fig. 1g), B. pulchella (2-4; Fig. 1e), R. fernandezae, Phyl. iheringii, and Phys. cuvieri (3-4; Fig. 1c-f-i), Li. macroglossa (3-5; Fig. 1a), O. americanus (2-5; Fig. 1k), Le. fuscus (1-5; Fig. 1h), V. uranoscopa (1-5; Fig. 1d), and E. bicolor (2-7; Fig. 1j).

TABLE I
Number of lines of arrested growth (LAGs), snout–vent length (SVL), and body mass (BM) of anurans from Subtropical climate.

		LAGs		SVL (mm)		BM (g)
Family	Species	Mean ± SD	Range	Mean ± SD	Range	Mean ± SD	Range
Alsodidade	Limnomedusa macroglossa	3.33 ± 0.58	3–5	54.49 ± 2.71	52.34–57.53	19.53 ± 7.46	16.00–28.10
Bufonidae	Melanophryniscus atroluteus	3.00 ± 0.00	2–3	21.73 ± 0.89	20.86–22.63	1.73 ± 0.21	1.50–1.90
	Rhinella fernandezae	3.67 ± 0.58	3–4	57.41 ± 6.84	45.84–62.25	15.93 ± 4.47	12.00–20.80
Centronelidae	Vitreorana uranoscopa	3.33 ± 1.53	1–5	23.36 ± 0.85	22.76–24.82	0.42 ± 0.14	0.25–0.50
Hylidae	Boana pulchella	3.00 ± 1.00	2–4	36.94 ± 5.65	32.94–44.20	3.47 ± 1.37	1.90–4.40
Hylodidae	Crossodactylus schmidti	2.33 ± 0.58	1–3	26.28 ± 0.95	25.61–29.61	2.00 ± 0.52	2.00–2.90
Leptodactylidae	Leptodactylus fuscus	3.33 ± 2.08	1–5	44.69 ± 0.81	44.11–46.47	9.00 ± 2.26	7.40–12.25
	Physalaemus cuvieri	3.33 ± 0.58	3–4	29.66 ± 0.66	29.04–30.35	2.57 ± 0.74	2.00–3.40
Mycrohylidae	Elachistocleis bicolor	5.00 ± 1.73	2–7	31.17 ± 2.67	29.43–34.24	3.40 ± 1.15	2.50–4.70
	Odontophrynidae americanos	3.00 ± 1.73	2–5	39.79 ± 9.19	31.37–49.49	10.77 ± 5.52	7.00–17.10
Phyllomedusidae	Phyllomedusa iheringii	3.33 ± 0.58	3–4	50.28 ± 2.52	48.5–53.20	7.50 ± 2.12	6.00–9.00

Figure 1
Cross-sections of the falanges showing the LAGs in (a) Limnomedusa macroglossa; (b) Melanophryniscus atroluteus; (c) Rhinella fernandezae; (d) Vitreorana uranoscopa; (e) Boana pulchella; (f) Phyllomedusa iheringii; (g) Crossodactylus schmidti; (h) Leptodactylus fuscus; (i) Physalaemus cuvieri; (j) Elachistocleis bicolor; and (k) Odontophrynus americanus.

Skeletochronology was effective for both phalanges and long bones, since all matched the corresponding number of LAGs for each specimen studied. Furthermore, skeletochronology can be a non-lethal procedure if performed using the specimens’ phalanges solely (Sinsch et al. 2007, Ginnan et al. 2014, Sinsch 2015, Hudson et al. 2017), since using long bones demands the euthanized of the specimens. Besides, LAGs are more evident in phalanges than in long bones, thus, phalanges are the most suitable bones for determining age in anurans (Kumbar and Pancharatna 2001). Another advantage of the method is the possibility of analyzing specimens from museum collections, without having to capture new specimens (see Sinsch 2015).

Because of the low sample of specimens per species herein analyzed, we consider this study as an exploratory work, providing evidence that this method is effective in estimating the age of subtropical climate anurans of southern Brazil. Additionally, this contribution presents the first record of LAGs to 11 native species of southern Brazil. Thereby, we encourage the development of new studies regarding anurans species from tropical and subtropical regions, to better understand the evolution of ecological patterns associated to this environment, and their significance in a broader view concerning anuran amphibians, one of the most ecologically endangered group of vertebrates worldwide.

ACKNOWLEGMENTS

We thank friends of Herpetology Laboratory of Federal University of Santa Maria (UFSM), Brazil, for helpful comments, suggestion and discussions, and specially thank Maurício Garcia (UFSM) for comments improving the quality of this manuscript.

REFERENCES

• ALVARES CA, STAPE JL, SENTELHAS PC, GONÇALVES JLM and SPAROVEK G. 2013. Köppen’s climate classification map for Brazil. Meteorologische Zeitschrift 22: 711-728.
• AVENS L, TAYLOR CJ, GOSHE LR, JONES TT and HASTINGS M. 2009. Use of skeletochronological analysis to estimate the age of leatherback sea turtles Dermochelys coriacea in the western North Atlantic. Endanger Species Res 8: 165-177.
• BIONDA CL, KOST S, SALAS NE, LAJMANOVICH RC, SINSCH U and MARTINO AL. 2015. Age structure, growth and longevity in the common toad, Rhinella arenarum, from Argentina. Acta Herpetol 10: 55-62
• BOTH C, KAEFER IL, SANTOS TG and CECHIN SZ. 2008. An austral anuran assemblage in the neotropics: seasonal occurrence correlated with photoperiod. J Nat Hist 42: 205-222.
• BOTHA J and CHINSAMY A. 2000. Growth patterns deduced from the bone histology of the Cynodonts Diamodon and Cynognathus. J Vertebr Paleontol 20: 705-711.
• BOTHA-BRINK J, BENTO SOARES M and MARTINELLI AG. 2018. Osteohistology of Late Triassic prozostrodontian cynodonts from Brazil. PeerJ 6: e5029.
• BOULENGER GA. 1885. Second list of reptiles and batrachians from the Province Rio Grande do Sul, Brazil, sent to the Natural History Museum by Dr. H. von Ihering. J Nat Hist 16: 85-88.
• CAJADE R, MARANGONI F and GANGENOVA E. 2013. Age, body size and growth pattern of Argenteohyla siemersi pederseni (Anura: Hylidae) in northeastern Argentina. J Nat Hist 47: 237-251.
• CALDART VM, IOP S, LINGNAU R and CECHIN SZ. 2016. Calling activity of a stream-breeding frog from the austral neotropics: temporal patterns of activity and the role of environmental factors. Herpetologica 72: 90-97.
• CALDART VM, LOEBENS L, BRUM AJC, BATAIOLI L and CECHIN SZ. 2019. Reproductive cycle, size and age at sexual maturity, and sexual dimorphism in the stream-breeding frog Crossodactylus schmidti (Hylodidae). S Am J Herpetol 14(1): 1-11.
• CAPUTO LFG, GITIRANA LB and MANSO PPA. 2010. Técnicas Histológicas. In: Molinaro EM, Caputo LFG and Amendoeira MRR (Eds), Conceitos e Métodos para a Formação de Profissionais em Laboratórios de Saúde, Instituto Osvaldo Cruz, Rio de Janeiro, p. 89-188.
• CASTANET J and SMIRINA E. 1990. Introduction to the skeletochronological method in amphibians and reptiles. Annales des Sciences Naturelles Zoologie 11: 191-196.
• CASTANET J, VIEILLOT HF, RICQLES A and ZYLBERBERG L. 2003. The skeletal histology of the Amphibia. In: Heatwole H (Ed), Amphibian Biology, Surrey Beatty & Sons, Chipping Norton, p. 1587-1683.
• CASTANET J, VIEILLOT HF, MEUNIER FJ and RICQLES A. 1993. Bone and individual aging. Bone 7: 245-283.
• DUMÉRIL AMC and BIBRON G. 1841. Erpétologie Genérale ou Histoire Naturelle Complète dês Reptiles. In Librarie Enclyclopedique de Roret (Ed), Paris, p 680.
• ECHEVERRIA DD and FILIPELLO AM. 1990. Edad y crecimiento in Bufo arenarum (Anura,Bufonidae). Cuaderno Herpetologia 5: 25-31.
• ETEROVICK PC, CARNAVA LACOQ, NOJOSA DMB, SILVANO DL, SEGALLA MV and SAZIMA I. 2005. Amphibian declives in Brazil: an overview. Biotropica 37: 166-179.
• FITZINGER LJFJ. 1826. Neue Classification der Reptilien nach ihren Natürlichen Verwandtschaften nebst einer Verwandtschafts-Tafel und einem Verzeichnisse der Reptilien Sammlung des K. K. Zoologisch Museum’s zu Wien. In: Heubner JG (Ed), Vienna, Austria, p. 66.
• GALLARDO JM. 1957. Las subespecies argentinas de Bufo granulosus Spix. Revista del Museo Argentino de Ciencias Naturales 3: 337-374.
• GALLARDO JM. 1961. Anfibios anuros de Misiones con la descripción de una nueva espécie de Crossodactylus. Neotropica 7: 33-38.
• GIBBONS MM and MCCARTHY TK. 1983. Age determination of frogs and toads (Amphibia, Anura) from North-western Europe. Zool Scr 12: 145-151.
• GINNAN NA, LAWRENCE JR, RUSSEL MET, EGGETT DL and HATCH KA. 2014. Toe clipping does not affect the survival of Leopard frog (Rana pipiens). Copeia 4: 650-653.
• GOSHE LR, AVENS L, SCHARF FS and SOUTHWOOD AL. 2010. Estimation of age maturation and growth of Atlantic green turtles (Chelonia mydas) using skeletochronology. Marine Biology 157: 1725-1740.
• GUÉRIN-MÉNEVILLE FÉ. 1838. Iconographie du Règne Animal de G. Cuvier. In: Ballière JB (Ed), Paris.
• HUDSON CM, BROWN GP and SHINE R. 2017. Effects of toe-clipping on growth, body condition, and locomotion of cane toads (Rhinella marina). Copeia 2: 257-260.
• ITURRA-CID M, ORTIZ JC and IBARGÜENGOYTÍA NR. 2010. Age, size, and growth of the Chilean frog Pleurodema thaul (Anura: Leiuperidae): latitudinal and altitudinal effects. Copeia 4: 609-617.
• KAEFER IL, BOELTER RA and CECHIN SZ. 2007. Reproductive biology of the invasive bullfrog Lithobates catesbeianus in Southern Brazil. Ann Zool Fenn 44: 435-444.
• KUMBAR SM and PANCHARATNA K. 2001. Occurrence of growth marks in the cross sections of phalanges and long bone of limbs in tropical anurans. Herpetol Rev 32: 165-167.
• KUMBAR SM and LAD SB. 2017. Determination of age and longevity of road mortal Indian common toad Duttaphrynus melanostictus by skeletochronology. Russ J Herpetol 24: 217-222.
• KUSRINI MD and ALFORD RA. 2006. The application of skeletochronology to estimate ages of three species of frogs in West Java. Indonesia Herpetol Rev 37: 423-425.
• KWET A and MIRANDA T. 2001. Sobre la biologia y taxonomia del sapo negro Melanophryniscus atroluteus (Miranda Ribeiro, 1920). Herpetofauna 23: 19-27.
• LI C, LIAO WB, YANG ZS and ZHOU CQ. 2010. A skeletochronological estimation of age structure in a population of the Guenther’s frog, Hylarana guentheri, from western China. Acta Herpetol 5: 1-11.
• MACHADO IF, BÜHLER D, ABADIE M, JÚNIOR APSJ and SANTOS RR. 2014. Distribution extension of Vitreorana uranoscopa (Anura: Centronelidae) in the state of Rio Grande do Sul, southern Brazil. Herpetol Notes 7: 443-446.
• MARANGONI F, SCHAEFER E, CAJADE R and TEJEDO M. 2009. Growth-Mark Formation and Chronology of Two Neotropical Anuran Species. J Herpetol 43: 546-550.
• MIRANDA-RIBEIRO A. 1920. Os Brachycephalidae do Museu Paulista (com três espécies novas). Revista do Museu Paulista 12: 307-316.
• MÜLLER L. 1924. Neue laubfrösch aus dem staate Santa Catharina, S. O. Brasilien. Zoologischer Anzeiger 59: 233-238.
• NARVAES P and RODRIGUES MT. 2009. Taxonomic revision of Rhinella granulosa species group (Amphibia, Anura, Bufonidae), with a description of a new species. Arquivos de Zoologia 40: 1-73.
• OVERBECK GE, MÜLLER SC, FIDELIS A, PFADENHAUER J, PILLAR VD, BLANCO CC, BOLDRINI II, BOTH R and FORNECK ED. 2007. Brazil’s neglected biome: The South Brazilian Campos. Perspectives in Plant Ecology, Evol Systemat 9: 101-116.
• REBOUÇAS R, DA SILVA HR and SANUY D. 2018. Froghood: Postmetamorphic development of the rock river frog Thoropa miliaris (Spix, 1824) (Anura, Cycloramphidae). Acta Zool 99(2): 151-157.
• RICQLÈS AJ, PADIAN K, HORNER JR, LAMM ET and MYHRVOLD N. 2003. Osteohistology of Confucius sanctus (Therophoda: Aves). J Vertebr Paleontol 23: 373-386.
• ROSSET SD, BALDO D, LANZONE C and BASSO NG. 2006. Review of the Geographic distribution of diploid and tetraploid population of the Odontophrynus americanus species complex (Anura: Leptodactylidae). J Herpetol 40: 465-477.
• ROZENBLUT B and OGIELSKA M. 2005. Development and growth of long bones in European water frogs (Amphibia: Anura: Ranidae), with remarks on age determination. J Morphol 265: 304-317.
• SÁ R and GERHAU A. 1983. Observaciones sobre la biologia de Phyllomedusa iheringii Boulenger, 1885, (Anura, Hylidae). Boletín de la Sociedad Zoológica del Uruguay 1: 44-49.
• SANDER PM. 2000. Longbone histology of the Tendaguru sauropods: implications for growth and biology. Paleobiology 26: 466-488.
• SANTOS TG, IOP S and ALVES SS. 2014. Anfíbios dos Campos Sulinos: diversidade, lacunas de conhecimento, desafios para conservação e perspectivas. Herpetologia Brasileira 3.
• SCHNEIDER JG. 1799. Historia Amphibiorum Naturalis et Literarariae. Fasciculus Primus. In: Jena FF (Ed), Continens Ranas, Calamitas, Bufones, Salamandras et Hydros in Genera et Species Descriptos Notisque suis Distinctos.
• SINSCH U. 2015. Review: Skeletochronological assessment of demographic life-history traits in amphibians. Herpetol J 25: 5-13.
• SINSCH U, OROMI N and SANUY D. 2007. Growth marks in natterjack toad (Bufo calamita) bones: histological correlates of hibernation and aestivation periods. Herpetol J 17: 129-137.
• SOCHA M and OGIELSKA M. 2010. Age structure, size and growth rate of water frogs from central European natural Pelophylax ridibundus - Pelophylax esculentus mixed populations estimated by skeletochronology. Amphibia-Reptilia 31: 239-250.
• SUN Y, XIONG J, LV Y and ZHANG Y. 2016. Age, body size, and growth in a population of the Asiatic toad Bufo gargarizans from central China. Russ J Herpetol 23: 35-40.
• TESSA G, CROTTINI A, GIACOMA C, GUARINO FM, RANDRIANIRIA JE and ANDREONE F. 2017. Comparative longevity and age at sexual maturity in twelve rainforest frogs of the genera Boophis, Gephyromantis and Mantidactylus (Anura: Manellidae) from Madagascar. Phyllomedusa 16: 13-21.
• TÜTKEN T, PFRETZSCHNER HU, VENNEMANN TW, SUN G and WANG YD. 2004. Paleobiology and skeletochronology of Jurassic dinosaurs: implications from the histology and oxygen isotope compositions of bones. Palaeogeogr Palaeoclimatol Palaeoecol 206: 217-238.

APPENDIX

Voucher individuals analyzed in this study housed in the herpetological collection of the Federal University of Santa Maria (ZUFSM):

Crossodactylus schmidti (n = 3): BRAZIL: Rio Grande do Sul: Derrubadas, ZUFSM 4682, 5200, 5209.

Elachistocleis bicolor (n = 3): BRAZIL: Rio Grande do Sul: Santa Maria, ZUFSM 0046, 0879; Manoel Viana: ZUFSM 2466.

Boana pulchella (n = 3): BRAZIL: Rio Grande do Sul: Itaara, ZUFSM 4123; Vacaria: ZUFSM 6077; Santana do Livramento, 8473.

Leptodactylus fuscus (n = 3): BRAZIL: Rio Grande do Sul: Ibarama, ZUFSM 3784; São Borja, ZUFSM 5016, 5017.

Limnomedusa macroglossa (n = 3): BRAZIL: Rio Grande do Sul: Aceguá, ZUFSM 5109; Santa Maria, ZUFSM 8456; Santana do Livramento, ZUFSM 8493.

Melanophryniscus atroluteus (n = 3): BRAZIL: Rio Grande do Sul: São Borja, ZUFSM 4984, 4985, 4990.

Odontophrynus americanus (n = 3): BRAZIL: Rio Grande do Sul: Santa Maria, ZUFSM 2762; Dom Feliciano, ZUFSM 3055; São Francisco de Assis, ZUFSM 4462.

Phyllomedusa iheringii (n = 3): BRAZIL: Rio Grande do Sul: Santa Maria, ZUFSM 3051; Caçapava do Sul, ZUFSM 3370; São Sepé, ZUFSM 8082.

Physalaemus cuvieri (n = 3): BRAZIL: Rio Grande do Sul: Santa Maria, ZUFSM 0054, 0238, 1679.

Rhinella fernandezae (n= 3): BRAZIL: Rio Grande do Sul: Arroio Passo do Lava-Pé, ZUFSM 4089; São Borja, ZUFSM 8527, 8528.

Vitreorana uranoscopa (n = 3): BRAZIL: Rio Grande do Sul: Derrubadas, ZUFSM 4571, 4572, 4584.

Publication Dates

• Publication in this collection
  02 Dec 2019
• Date of issue
  2019

History

• Received
  10 Feb 2019
• Accepted
  7 Aug 2019